Merge branch 'master' into fixjdb1

Cargo.lock

@@ -2,7 +2,7 @@
 name = "parity"
 version = "0.9.99"
 dependencies = [
- "clippy 0.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clippy 0.0.49 (registry+https://github.com/rust-lang/crates.io-index)",
  "ctrlc 1.1.1 (git+https://github.com/tomusdrw/rust-ctrlc.git)",
  "daemonize 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "docopt 0.6.78 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -31,7 +31,7 @@ dependencies = [
 
 [[package]]
 name = "arrayvec"
-version = "0.3.15"
+version = "0.3.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "nodrop 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -43,14 +43,14 @@ name = "aster"
 version = "0.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "syntex_syntax 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.29.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "bigint"
 version = "0.1.0"
 dependencies = [
- "arrayvec 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "arrayvec 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -65,7 +65,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "bitflags"
-version = "0.4.0"
+version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -85,7 +85,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "chrono"
-version = "0.2.19"
+version = "0.2.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "num 0.1.31 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -94,7 +94,7 @@ dependencies = [
 
 [[package]]
 name = "clippy"
-version = "0.0.44"
+version = "0.0.49"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "regex-syntax 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -117,7 +117,7 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "time 0.1.34 (registry+https://github.com/rust-lang/crates.io-index)",
- "url 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 0.5.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -136,7 +136,7 @@ version = "1.1.1"
 source = "git+https://github.com/tomusdrw/rust-ctrlc.git#f4927770f89eca80ec250911eea3adcbf579ac48"
 dependencies = [
  "kernel32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -145,7 +145,7 @@ name = "daemonize"
 version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -161,7 +161,7 @@ name = "docopt"
 version = "0.6.78"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "regex 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "strsim 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -177,7 +177,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "log 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.55 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -185,7 +185,7 @@ name = "eth-secp256k1"
 version = "0.5.4"
 source = "git+https://github.com/ethcore/rust-secp256k1#283a0677d8327536be58a87e0494d7e0e7b1d1d8"
 dependencies = [
- "arrayvec 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "arrayvec 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "gcc 0.3.25 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -207,7 +207,7 @@ dependencies = [
 name = "ethcore"
 version = "0.9.99"
 dependencies = [
- "clippy 0.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clippy 0.0.49 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "ethash 0.9.99",
@@ -233,7 +233,7 @@ dependencies = [
 name = "ethcore-rpc"
 version = "0.9.99"
 dependencies = [
- "clippy 0.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clippy 0.0.49 (registry+https://github.com/rust-lang/crates.io-index)",
  "ethash 0.9.99",
  "ethcore 0.9.99",
  "ethcore-util 0.9.99",
@@ -253,10 +253,10 @@ dependencies = [
 name = "ethcore-util"
 version = "0.9.99"
 dependencies = [
- "arrayvec 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "arrayvec 0.3.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "bigint 0.1.0",
- "chrono 0.2.19 (registry+https://github.com/rust-lang/crates.io-index)",
+ "chrono 0.2.20 (registry+https://github.com/rust-lang/crates.io-index)",
- "clippy 0.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clippy 0.0.49 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "elastic-array 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -264,14 +264,14 @@ dependencies = [
  "ethcore-devtools 0.9.99",
  "heapsize 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "igd 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "itertools 0.4.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.4.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "json-tests 0.1.0",
  "lazy_static 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "mio 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "rocksdb 0.4.1 (git+https://github.com/arkpar/rust-rocksdb.git)",
+ "rocksdb 0.4.2 (git+https://github.com/arkpar/rust-rocksdb.git)",
  "rust-crypto 0.2.34 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -288,7 +288,7 @@ dependencies = [
 name = "ethsync"
 version = "0.9.99"
 dependencies = [
- "clippy 0.0.44 (registry+https://github.com/rust-lang/crates.io-index)",
+ "clippy 0.0.49 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "ethcore 0.9.99",
  "ethcore-util 0.9.99",
@@ -304,7 +304,7 @@ dependencies = [
 name = "fdlimit"
 version = "0.1.0"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -314,7 +314,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "glob"
-version = "0.2.10"
+version = "0.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -328,7 +328,7 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "kernel32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.55 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -381,7 +381,7 @@ dependencies = [
  "traitobject 0.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "typeable 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicase 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "url 0.5.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "url 0.5.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -391,21 +391,21 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "hyper 0.6.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 0.1.55 (registry+https://github.com/rust-lang/crates.io-index)",
  "xml-rs 0.1.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "xmltree 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "itertools"
-version = "0.4.10"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "json-tests"
 version = "0.1.0"
 dependencies = [
- "glob 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "glob 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -461,16 +461,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "libc"
-version = "0.2.7"
+version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "librocksdb-sys"
-version = "0.2.1"
+version = "0.2.2"
-source = "git+https://github.com/arkpar/rust-rocksdb.git#2156621f583bda95c1c07e89e79e4019f75158ee"
+source = "git+https://github.com/arkpar/rust-rocksdb.git#a4f89fea20ee3ae92b692df65d56426a5c0b6fd5"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "pkg-config 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -478,7 +477,7 @@ name = "log"
 version = "0.3.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -491,7 +490,7 @@ name = "memchr"
 version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -537,7 +536,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "kernel32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "ws2_32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -561,7 +560,7 @@ dependencies = [
 
 [[package]]
 name = "nom"
-version = "1.2.1"
+version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -578,7 +577,7 @@ name = "num_cpus"
 version = "0.2.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -594,11 +593,6 @@ name = "odds"
 version = "0.2.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
-[[package]]
-name = "pkg-config"
-version = "0.3.7"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
 name = "primal"
 version = "0.2.3"
@@ -645,7 +639,7 @@ name = "quasi"
 version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "syntex_syntax 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.29.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -655,7 +649,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "aster 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "syntex 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "syntex_syntax 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.29.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -663,7 +657,7 @@ name = "rand"
 version = "0.3.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -678,7 +672,7 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "0.1.54"
+version = "0.1.55"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "aho-corasick 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -694,11 +688,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "rocksdb"
-version = "0.4.1"
+version = "0.4.2"
-source = "git+https://github.com/arkpar/rust-rocksdb.git#2156621f583bda95c1c07e89e79e4019f75158ee"
+source = "git+https://github.com/arkpar/rust-rocksdb.git#a4f89fea20ee3ae92b692df65d56426a5c0b6fd5"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "librocksdb-sys 0.2.1 (git+https://github.com/arkpar/rust-rocksdb.git)",
+ "librocksdb-sys 0.2.2 (git+https://github.com/arkpar/rust-rocksdb.git)",
 ]
 
 [[package]]
@@ -707,7 +701,7 @@ version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "kernel32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "termios 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -747,7 +741,7 @@ name = "semver"
 version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "nom 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "nom 1.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -772,7 +766,7 @@ dependencies = [
  "quasi 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quasi_codegen 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "syntex 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "syntex_syntax 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.29.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -815,16 +809,16 @@ name = "syntex"
 version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "syntex_syntax 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syntex_syntax 0.29.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "syntex_syntax"
-version = "0.29.0"
+version = "0.29.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "term 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -850,7 +844,7 @@ name = "termios"
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -859,7 +853,7 @@ version = "0.1.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "kernel32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -924,7 +918,7 @@ dependencies = [
 
 [[package]]
 name = "url"
-version = "0.5.5"
+version = "0.5.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -981,7 +975,7 @@ name = "xml-rs"
 version = "0.1.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "bitflags 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]

Cargo.toml

@@ -19,7 +19,7 @@ ctrlc = { git = "https://github.com/tomusdrw/rust-ctrlc.git" }
 fdlimit = { path = "util/fdlimit" }
 daemonize = "0.2"
 number_prefix = "0.2"
-clippy = { version = "0.0.44", optional = true }
+clippy = { version = "0.0.49", optional = true }
 ethcore = { path = "ethcore" }
 ethcore-util = { path = "util" }
 ethsync = { path = "sync" }

ethcore/Cargo.toml

@@ -17,7 +17,7 @@ ethcore-util = { path = "../util" }
 evmjit = { path = "../evmjit", optional = true }
 ethash = { path = "../ethash" }
 num_cpus = "0.2"
-clippy = { version = "0.0.44", optional = true }
+clippy = { version = "0.0.49", optional = true }
 crossbeam = "0.1.5"
 lazy_static = "0.1"
 ethcore-devtools = { path = "../devtools" }

ethcore/src/account_db.rs

@@ -13,17 +13,14 @@ pub struct AccountDB<'db> {
 
 #[inline]
 fn combine_key<'a>(address: &'a H256, key: &'a H256) -> H256 {
-	let mut addr_hash = address.sha3();
+	address ^ key
-	// preserve 96 bits of original key for db lookup
-	addr_hash[0..12].clone_from_slice(&[0u8; 12]); 
-	&addr_hash ^ key
 }
 
 impl<'db> AccountDB<'db> {
 	pub fn new(db: &'db HashDB, address: &Address) -> AccountDB<'db> {
 		AccountDB {
 			db: db,
-			address: x!(address.clone()),
+			address: x!(address),
 		}
 	}
 }
@@ -70,7 +67,7 @@ impl<'db> AccountDBMut<'db> {
 	pub fn new(db: &'db mut HashDB, address: &Address) -> AccountDBMut<'db> {
 		AccountDBMut {
 			db: db,
-			address: x!(address.clone()),
+			address: x!(address),
 		}
 	}
 

ethcore/src/client/client.rs

@@ -116,7 +116,7 @@ pub struct Client<V = CanonVerifier> where V: Verifier {
 }
 
 const HISTORY: u64 = 1000;
-const CLIENT_DB_VER_STR: &'static str = "5.1";
+const CLIENT_DB_VER_STR: &'static str = "5.2";
 
 impl Client<CanonVerifier> {
 	/// Create a new client with given spec and DB path.

ethcore/src/extras.rs

@@ -35,13 +35,13 @@ pub enum ExtrasIndex {
 	BlocksBlooms = 4,
 	/// Block receipts index
 	BlockReceipts = 5,
-} 
+}
 
 /// trait used to write Extras data to db
 pub trait ExtrasWritable {
 	/// Write extra data to db
 	fn put_extras<K, T>(&self, hash: &K, value: &T) where
-		T: ExtrasIndexable + Encodable, 
+		T: ExtrasIndexable + Encodable,
 		K: ExtrasSliceConvertable;
 }
 
@@ -60,9 +60,9 @@ pub trait ExtrasReadable {
 
 impl ExtrasWritable for DBTransaction {
 	fn put_extras<K, T>(&self, hash: &K, value: &T) where
-		T: ExtrasIndexable + Encodable, 
+		T: ExtrasIndexable + Encodable,
 		K: ExtrasSliceConvertable {
-		
+
 		self.put(&hash.to_extras_slice(T::extras_index()), &encode(value)).unwrap()
 	}
 }
@@ -215,6 +215,12 @@ pub struct BlocksBlooms {
 	pub blooms: [H2048; 16],
 }
 
+impl Default for BlocksBlooms {
+	fn default() -> Self {
+		BlocksBlooms::new()
+	}
+}
+
 impl BlocksBlooms {
 	pub fn new() -> Self {
 		BlocksBlooms { blooms: unsafe { ::std::mem::zeroed() }}

ethcore/src/lib.rs

@@ -25,6 +25,8 @@
 #![cfg_attr(feature="dev", allow(match_bool))]
 // Keeps consistency (all lines with `.clone()`) and helpful when changing ref to non-ref.
 #![cfg_attr(feature="dev", allow(clone_on_copy))]
+// In most cases it expresses function flow better
+#![cfg_attr(feature="dev", allow(if_not_else))]
 
 //! Ethcore library
 //!

ethcore/src/substate.rs

@@ -31,6 +31,12 @@ pub struct Substate {
 	pub contracts_created: Vec<Address>
 }
 
+impl Default for Substate {
+	fn default() -> Self {
+		Substate::new()
+	}
+}
+
 impl Substate {
 	/// Creates new substate.
 	pub fn new() -> Self {
@@ -67,8 +73,8 @@ mod tests {
 		let mut sub_state = Substate::new();
 		sub_state.contracts_created.push(address_from_u64(1u64));
 		sub_state.logs.push(LogEntry {
-			address: address_from_u64(1u64), 
+			address: address_from_u64(1u64),
-			topics: vec![], 
+			topics: vec![],
 			data: vec![]
 		});
 		sub_state.sstore_clears_count = x!(5);
@@ -77,8 +83,8 @@ mod tests {
 		let mut sub_state_2 = Substate::new();
 		sub_state_2.contracts_created.push(address_from_u64(2u64));
 		sub_state_2.logs.push(LogEntry {
-			address: address_from_u64(1u64), 
+			address: address_from_u64(1u64),
-			topics: vec![], 
+			topics: vec![],
 			data: vec![]
 		});
 		sub_state_2.sstore_clears_count = x!(7);

parity/main.rs

@@ -81,10 +81,9 @@ Protocol Options:
   --testnet                Equivalent to --chain testnet (geth-compatible).
   --networkid INDEX        Override the network identifier from the chain we are on.
   --pruning METHOD         Configure pruning of the state/storage trie. METHOD may be one of: archive,
-                           light (experimental) [default: archive].
+                           light (experimental), fast (experimental) [default: archive].
   -d --datadir PATH        Specify the database & configuration directory path [default: $HOME/.parity]
   --db-path PATH           Specify the database & configuration directory path [default: $HOME/.parity]
-  --pruning                Client should prune the state/storage trie.
   --keys-path PATH         Specify the path for JSON key files to be found [default: $HOME/.web3/keys]
   --identity NAME          Specify your node's name.
 
@@ -425,7 +424,7 @@ impl Configuration {
 			"" => journaldb::Algorithm::Archive,
 			"archive" => journaldb::Algorithm::Archive,
 			"pruned" => journaldb::Algorithm::EarlyMerge,
-//			"fast" => journaldb::Algorithm::OverlayRecent,	// TODO: @arkpar uncomment this once option 2 is merged.
+			"fast" => journaldb::Algorithm::OverlayRecent,
 //			"slow" => journaldb::Algorithm::RefCounted,		// TODO: @gavofyork uncomment this once ref-count algo is merged.
 			_ => { die!("Invalid pruning method given."); }
 		};

rpc/Cargo.toml

@@ -18,7 +18,7 @@ ethcore-util = { path = "../util" }
 ethcore = { path = "../ethcore" }
 ethash = { path = "../ethash" }
 ethsync = { path = "../sync" }
-clippy = { version = "0.0.44", optional = true }
+clippy = { version = "0.0.49", optional = true }
 rustc-serialize = "0.3"
 transient-hashmap = "0.1"
 serde_macros = { version = "0.7.0", optional = true }

sync/Cargo.toml

@@ -10,7 +10,7 @@ authors = ["Ethcore <admin@ethcore.io"]
 [dependencies]
 ethcore-util = { path = "../util" }
 ethcore = { path = "../ethcore" }
-clippy = { version = "0.0.44", optional = true }
+clippy = { version = "0.0.49", optional = true }
 log = "0.3"
 env_logger = "0.3"
 time = "0.1.34"

sync/src/lib.rs

@@ -17,9 +17,10 @@
 #![warn(missing_docs)]
 #![cfg_attr(feature="dev", feature(plugin))]
 #![cfg_attr(feature="dev", plugin(clippy))]
-
 // Keeps consistency (all lines with `.clone()`) and helpful when changing ref to non-ref.
 #![cfg_attr(feature="dev", allow(clone_on_copy))]
+// In most cases it expresses function flow better
+#![cfg_attr(feature="dev", allow(if_not_else))]
 
 //! Blockchain sync module
 //! Implements ethereum protocol version 63 as specified here:
@@ -173,6 +174,7 @@ impl NetworkProtocolHandler<SyncMessage> for EthSync {
 		self.sync.write().unwrap().maintain_sync(&mut NetSyncIo::new(io, self.chain.deref()));
 	}
 
+	#[allow(single_match)]
 	fn message(&self, io: &NetworkContext<SyncMessage>, message: &SyncMessage) {
 		match *message {
 			SyncMessage::NewChainBlocks { ref good, ref bad, ref retracted } => {

sync/src/transaction_queue.rs

@@ -79,6 +79,7 @@
 //!		- When it's removed from `current` - all transactions from this sender (`current` & `future`) are recalculated.
 //!
 
+use std::default::Default;
 use std::cmp::{Ordering};
 use std::collections::{HashMap, BTreeSet};
 use util::numbers::{Uint, U256};
@@ -102,6 +103,7 @@ struct TransactionOrder {
 	hash: H256,
 }
 
+
 impl TransactionOrder {
 	fn for_transaction(tx: &VerifiedTransaction, base_nonce: U256) -> Self {
 		TransactionOrder {
@@ -253,6 +255,12 @@ pub struct TransactionQueue {
 	last_nonces: HashMap<Address, U256>,
 }
 
+impl Default for TransactionQueue {
+	fn default() -> Self {
+		TransactionQueue::new()
+	}
+}
+
 impl TransactionQueue {
 	/// Creates new instance of this Queue
 	pub fn new() -> Self {

util/Cargo.toml

@@ -27,7 +27,7 @@ crossbeam = "0.2"
 slab = "0.1"
 sha3 = { path = "sha3" }
 serde = "0.7.0"
-clippy = { version = "0.0.44", optional = true }
+clippy = { version = "0.0.49", optional = true }
 json-tests = { path = "json-tests" }
 rustc_version = "0.1.0"
 igd = "0.4.2"

util/bigint/Cargo.toml

@@ -15,7 +15,6 @@ rustc-serialize = "0.3"
 arrayvec = "0.3"
 rand = "0.3.12"
 serde = "0.7.0"
-clippy = { version = "0.0.44", optional = true }
 heapsize = "0.3"
 
 [features]

util/src/journaldb/earlymergedb.rs

@@ -60,7 +60,7 @@ enum RemoveFrom {
 /// write operations out to disk. Unlike OverlayDB, `remove()` operations do not take effect
 /// immediately. Rather some age (based on a linear but arbitrary metric) must pass before
 /// the removals actually take effect.
-pub struct OptionOneDB {
+pub struct EarlyMergeDB {
 	overlay: MemoryDB,
 	backing: Arc<Database>,
 	refs: Option<Arc<RwLock<HashMap<H256, RefInfo>>>>,
@@ -72,9 +72,9 @@ const VERSION_KEY : [u8; 12] = [ b'j', b'v', b'e', b'r', 0, 0, 0, 0, 0, 0, 0, 0
 const DB_VERSION : u32 = 3;
 const PADDING : [u8; 10] = [ 0u8; 10 ];
 
-impl OptionOneDB {
+impl EarlyMergeDB {
 	/// Create a new instance from file
-	pub fn new(path: &str) -> OptionOneDB {
+	pub fn new(path: &str) -> EarlyMergeDB {
 		let opts = DatabaseConfig {
 			prefix_size: Some(12) //use 12 bytes as prefix, this must match account_db prefix
 		};
@@ -90,8 +90,8 @@ impl OptionOneDB {
 			backing.put(&VERSION_KEY, &encode(&DB_VERSION)).expect("Error writing version to database");
 		}
 
-		let refs = Some(Arc::new(RwLock::new(OptionOneDB::read_refs(&backing))));
+		let refs = Some(Arc::new(RwLock::new(EarlyMergeDB::read_refs(&backing))));
-		OptionOneDB {
+		EarlyMergeDB {
 			overlay: MemoryDB::new(),
 			backing: Arc::new(backing),
 			refs: refs,
@@ -100,7 +100,7 @@ impl OptionOneDB {
 
 	/// Create a new instance with an anonymous temporary database.
 	#[cfg(test)]
-	fn new_temp() -> OptionOneDB {
+	fn new_temp() -> EarlyMergeDB {
 		let mut dir = env::temp_dir();
 		dir.push(H32::random().hex());
 		Self::new(dir.to_str().unwrap())
@@ -269,7 +269,7 @@ impl OptionOneDB {
 	}
  }
 
-impl HashDB for OptionOneDB {
+impl HashDB for EarlyMergeDB {
 	fn keys(&self) -> HashMap<H256, i32> {
 		let mut ret: HashMap<H256, i32> = HashMap::new();
 		for (key, _) in self.backing.iter() {
@@ -314,9 +314,9 @@ impl HashDB for OptionOneDB {
 	}
 }
 
-impl JournalDB for OptionOneDB {
+impl JournalDB for EarlyMergeDB {
 	fn spawn(&self) -> Box<JournalDB> {
-		Box::new(OptionOneDB {
+		Box::new(EarlyMergeDB {
 			overlay: MemoryDB::new(),
 			backing: self.backing.clone(),
 			refs: self.refs.clone(),
@@ -498,7 +498,7 @@ impl JournalDB for OptionOneDB {
 				index += 1;
 			}
 			if trace {
-				trace!(target: "jdb", "delete journal for time #{}.{}, (canon was {})", end_era, index, canon_id);
+				trace!(target: "jdb", "EarlyMergeDB: delete journal for time #{}.{}, (canon was {})", end_era, index, canon_id);
 			}
 		}
 
@@ -525,7 +525,7 @@ mod tests {
 	#[test]
 	fn insert_same_in_fork() {
 		// history is 1
-		let mut jdb = OptionOneDB::new_temp();
+		let mut jdb = EarlyMergeDB::new_temp();
 
 		let x = jdb.insert(b"X");
 		jdb.commit(1, &b"1".sha3(), None).unwrap();
@@ -555,7 +555,7 @@ mod tests {
 	#[test]
 	fn long_history() {
 		// history is 3
-		let mut jdb = OptionOneDB::new_temp();
+		let mut jdb = EarlyMergeDB::new_temp();
 		let h = jdb.insert(b"foo");
 		jdb.commit(0, &b"0".sha3(), None).unwrap();
 		assert!(jdb.can_reconstruct_refs());
@@ -578,7 +578,7 @@ mod tests {
 	#[test]
 	fn complex() {
 		// history is 1
-		let mut jdb = OptionOneDB::new_temp();
+		let mut jdb = EarlyMergeDB::new_temp();
 
 		let foo = jdb.insert(b"foo");
 		let bar = jdb.insert(b"bar");
@@ -621,7 +621,7 @@ mod tests {
 	#[test]
 	fn fork() {
 		// history is 1
-		let mut jdb = OptionOneDB::new_temp();
+		let mut jdb = EarlyMergeDB::new_temp();
 
 		let foo = jdb.insert(b"foo");
 		let bar = jdb.insert(b"bar");
@@ -653,7 +653,7 @@ mod tests {
 	#[test]
 	fn overwrite() {
 		// history is 1
-		let mut jdb = OptionOneDB::new_temp();
+		let mut jdb = EarlyMergeDB::new_temp();
 
 		let foo = jdb.insert(b"foo");
 		jdb.commit(0, &b"0".sha3(), None).unwrap();
@@ -678,7 +678,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 
-		let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 		jdb.commit(0, &b"0".sha3(), None).unwrap();
 		assert!(jdb.can_reconstruct_refs());
 
@@ -706,7 +706,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 
-		let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 		jdb.commit(0, &b"0".sha3(), None).unwrap();
 		assert!(jdb.can_reconstruct_refs());
 
@@ -734,7 +734,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 
-		let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 		jdb.commit(0, &b"0".sha3(), None).unwrap();
 		assert!(jdb.can_reconstruct_refs());
 
@@ -772,7 +772,7 @@ mod tests {
 		let bar = H256::random();
 
 		let foo = {
-			let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+			let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 			// history is 1
 			let foo = jdb.insert(b"foo");
 			jdb.emplace(bar.clone(), b"bar".to_vec());
@@ -782,14 +782,14 @@ mod tests {
 		};
 
 		{
-			let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+			let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 			jdb.remove(&foo);
 			jdb.commit(1, &b"1".sha3(), Some((0, b"0".sha3()))).unwrap();
 			assert!(jdb.can_reconstruct_refs());
 		}
 
 		{
-			let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+			let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 			assert!(jdb.exists(&foo));
 			assert!(jdb.exists(&bar));
 			jdb.commit(2, &b"2".sha3(), Some((1, b"1".sha3()))).unwrap();
@@ -804,7 +804,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 
-		let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 
 		// history is 4
 		let foo = jdb.insert(b"foo");
@@ -833,7 +833,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 
-		let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 
 		// history is 4
 		let foo = jdb.insert(b"foo");
@@ -882,7 +882,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 
-		let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 		// history is 1
 		let foo = jdb.insert(b"foo");
 		jdb.commit(1, &b"1".sha3(), Some((0, b"0".sha3()))).unwrap();
@@ -913,7 +913,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 
-		let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 		// history is 4
 		let foo = jdb.insert(b"foo");
 		jdb.commit(0, &b"0".sha3(), None).unwrap();
@@ -953,7 +953,7 @@ mod tests {
 		let foo = b"foo".sha3();
 
 		{
-			let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+			let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 			// history is 1
 			jdb.insert(b"foo");
 			jdb.commit(0, &b"0".sha3(), None).unwrap();
@@ -974,7 +974,7 @@ mod tests {
 			assert!(jdb.exists(&foo));
 
 		// incantation to reopen the db
-		}; { let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		}; { let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 
 			jdb.remove(&foo);
 			jdb.commit(4, &b"4".sha3(), Some((2, b"2".sha3()))).unwrap();
@@ -982,14 +982,14 @@ mod tests {
 			assert!(jdb.exists(&foo));
 
 		// incantation to reopen the db
-		}; { let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		}; { let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 
 			jdb.commit(5, &b"5".sha3(), Some((3, b"3".sha3()))).unwrap();
 			assert!(jdb.can_reconstruct_refs());
 			assert!(jdb.exists(&foo));
 
 		// incantation to reopen the db
-		}; { let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+		}; { let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 
 			jdb.commit(6, &b"6".sha3(), Some((4, b"4".sha3()))).unwrap();
 			assert!(jdb.can_reconstruct_refs());
@@ -1002,7 +1002,7 @@ mod tests {
 		let mut dir = ::std::env::temp_dir();
 		dir.push(H32::random().hex());
 		let (foo, bar, baz) = {
-			let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+			let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 			// history is 1
 			let foo = jdb.insert(b"foo");
 			let bar = jdb.insert(b"bar");
@@ -1020,7 +1020,7 @@ mod tests {
 		};
 
 		{
-			let mut jdb = OptionOneDB::new(dir.to_str().unwrap());
+			let mut jdb = EarlyMergeDB::new(dir.to_str().unwrap());
 			jdb.commit(2, &b"2b".sha3(), Some((1, b"1b".sha3()))).unwrap();
 			assert!(jdb.can_reconstruct_refs());
 			assert!(jdb.exists(&foo));

util/src/journaldb/mod.rs

@@ -21,7 +21,8 @@ use common::*;
 /// Export the journaldb module.
 pub mod traits;
 mod archivedb;
-mod optiononedb;
+mod earlymergedb;
+mod overlayrecentdb;
 
 /// Export the JournalDB trait.
 pub use self::traits::JournalDB;
@@ -72,7 +73,8 @@ impl fmt::Display for Algorithm {
 pub fn new(path: &str, algorithm: Algorithm) -> Box<JournalDB> {
 	match algorithm {
 		Algorithm::Archive => Box::new(archivedb::ArchiveDB::new(path)),
-		Algorithm::EarlyMerge => Box::new(optiononedb::OptionOneDB::new(path)),
+		Algorithm::EarlyMerge => Box::new(earlymergedb::EarlyMergeDB::new(path)),
+		Algorithm::OverlayRecent => Box::new(overlayrecentdb::OverlayRecentDB::new(path)),
 		_ => unimplemented!(),
 	}
 }

util/src/journaldb/overlayrecentdb.rs

@@ -0,0 +1,873 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+//! JournalDB over in-memory overlay
+
+use common::*;
+use rlp::*;
+use hashdb::*;
+use memorydb::*;
+use kvdb::{Database, DBTransaction, DatabaseConfig};
+#[cfg(test)]
+use std::env;
+use super::JournalDB;
+
+/// Implementation of the JournalDB trait for a disk-backed database with a memory overlay
+/// and, possibly, latent-removal semantics.
+///
+/// Like OverlayDB, there is a memory overlay; `commit()` must be called in order to
+/// write operations out to disk. Unlike OverlayDB, `remove()` operations do not take effect
+/// immediately. Rather some age (based on a linear but arbitrary metric) must pass before
+/// the removals actually take effect.
+///
+/// There are two memory overlays: 
+/// - Transaction overlay contains current transaction data. It is merged with with history 
+/// overlay on each `commit()`
+/// - History overlay contains all data inserted during the history period. When the node 
+/// in the overlay becomes ancient it is written to disk on `commit()`
+///
+/// There is also a journal maintained in memory and on the disk as well which lists insertions 
+/// and removals for each commit during the history period. This is used to track 
+/// data nodes that go out of history scope and must be written to disk.
+///
+/// Commit workflow:
+/// 1. Create a new journal record from the transaction overlay.
+/// 2. Inseart each node from the transaction overlay into the History overlay increasing reference
+/// count if it is already there. Note that the reference counting is managed by `MemoryDB`
+/// 3. Clear the transaction overlay.
+/// 4. For a canonical journal record that becomes ancient inserts its insertions into the disk DB
+/// 5. For each journal record that goes out of the history scope (becomes ancient) remove its
+/// insertions from the history overlay, decreasing the reference counter and removing entry if 
+/// if reaches zero.
+/// 6. For a canonical journal record that becomes ancient delete its removals from the disk only if 
+/// the removed key is not present in the history overlay.
+/// 7. Delete ancient record from memory and disk.
+/// 
+pub struct OverlayRecentDB {
+	transaction_overlay: MemoryDB,
+	backing: Arc<Database>,
+	journal_overlay: Arc<RwLock<JournalOverlay>>,
+}
+
+#[derive(PartialEq)]
+struct JournalOverlay {
+	backing_overlay: MemoryDB,
+	journal: HashMap<u64, Vec<JournalEntry>>,
+	latest_era: u64,
+}
+
+#[derive(PartialEq)]
+struct JournalEntry {
+	id: H256,
+	insertions: Vec<H256>,
+	deletions: Vec<H256>,
+}
+
+impl HeapSizeOf for JournalEntry {
+	fn heap_size_of_children(&self) -> usize {
+		self.insertions.heap_size_of_children() + self.deletions.heap_size_of_children()
+	}
+}
+
+impl Clone for OverlayRecentDB {
+	fn clone(&self) -> OverlayRecentDB {
+		OverlayRecentDB {
+			transaction_overlay: MemoryDB::new(),
+			backing: self.backing.clone(),
+			journal_overlay: self.journal_overlay.clone(),
+		}
+	}
+}
+
+// all keys must be at least 12 bytes
+const LATEST_ERA_KEY : [u8; 12] = [ b'l', b'a', b's', b't', 0, 0, 0, 0, 0, 0, 0, 0 ];
+const VERSION_KEY : [u8; 12] = [ b'j', b'v', b'e', b'r', 0, 0, 0, 0, 0, 0, 0, 0 ];
+const DB_VERSION : u32 = 0x200 + 3;
+const PADDING : [u8; 10] = [ 0u8; 10 ];
+
+impl OverlayRecentDB {
+	/// Create a new instance from file
+	pub fn new(path: &str) -> OverlayRecentDB {
+		Self::from_prefs(path)
+	}
+
+	/// Create a new instance from file
+	pub fn from_prefs(path: &str) -> OverlayRecentDB {
+		let opts = DatabaseConfig {
+			prefix_size: Some(12) //use 12 bytes as prefix, this must match account_db prefix
+		};
+		let backing = Database::open(&opts, path).unwrap_or_else(|e| {
+			panic!("Error opening state db: {}", e);
+		});
+		if !backing.is_empty() {
+			match backing.get(&VERSION_KEY).map(|d| d.map(|v| decode::<u32>(&v))) {
+				Ok(Some(DB_VERSION)) => {}
+				v => panic!("Incompatible DB version, expected {}, got {:?}", DB_VERSION, v)
+			}
+		} else {
+			backing.put(&VERSION_KEY, &encode(&DB_VERSION)).expect("Error writing version to database");
+		}
+
+		let journal_overlay = Arc::new(RwLock::new(OverlayRecentDB::read_overlay(&backing)));
+		OverlayRecentDB {
+			transaction_overlay: MemoryDB::new(),
+			backing: Arc::new(backing),
+			journal_overlay: journal_overlay,
+		}
+	}
+
+	/// Create a new instance with an anonymous temporary database.
+	#[cfg(test)]
+	pub fn new_temp() -> OverlayRecentDB {
+		let mut dir = env::temp_dir();
+		dir.push(H32::random().hex());
+		Self::new(dir.to_str().unwrap())
+	}
+
+	#[cfg(test)]
+	fn can_reconstruct_refs(&self) -> bool {
+		let reconstructed = Self::read_overlay(&self.backing);
+		let journal_overlay = self.journal_overlay.read().unwrap();
+		*journal_overlay == reconstructed
+	}
+
+	fn payload(&self, key: &H256) -> Option<Bytes> {
+		self.backing.get(&key.bytes()).expect("Low-level database error. Some issue with your hard disk?").map(|v| v.to_vec())
+	}
+
+	fn read_overlay(db: &Database) -> JournalOverlay {
+		let mut journal = HashMap::new();
+		let mut overlay = MemoryDB::new();
+		let mut count = 0;
+		let mut latest_era = 0;
+		if let Some(val) = db.get(&LATEST_ERA_KEY).expect("Low-level database error.") {
+			latest_era = decode::<u64>(&val);
+			let mut era = latest_era;
+			loop {
+				let mut index = 0usize;
+				while let Some(rlp_data) = db.get({
+					let mut r = RlpStream::new_list(3);
+					r.append(&era);
+					r.append(&index);
+					r.append(&&PADDING[..]);
+					&r.drain()
+				}).expect("Low-level database error.") {
+					trace!("read_overlay: era={}, index={}", era, index);
+					let rlp = Rlp::new(&rlp_data);
+					let id: H256 = rlp.val_at(0);
+					let insertions = rlp.at(1);
+					let deletions: Vec<H256> = rlp.val_at(2);
+					let mut inserted_keys = Vec::new();
+					for r in insertions.iter() {
+						let k: H256 = r.val_at(0);
+						let v: Bytes = r.val_at(1);
+						overlay.emplace(k.clone(), v);
+						inserted_keys.push(k);
+						count += 1;
+					}
+					journal.entry(era).or_insert_with(Vec::new).push(JournalEntry {
+						id: id,
+						insertions: inserted_keys,
+						deletions: deletions,
+					});
+					index += 1;
+				};
+				if index == 0 || era == 0 {
+					break;
+				}
+				era -= 1;
+			}
+		}
+		trace!("Recovered {} overlay entries, {} journal entries", count, journal.len());
+		JournalOverlay { backing_overlay: overlay, journal: journal, latest_era: latest_era }
+	}
+}
+
+impl JournalDB for OverlayRecentDB {
+	fn spawn(&self) -> Box<JournalDB> {
+		Box::new(self.clone())
+	}
+
+	fn mem_used(&self) -> usize {
+		let mut mem = self.transaction_overlay.mem_used();
+		let overlay = self.journal_overlay.read().unwrap();
+		mem += overlay.backing_overlay.mem_used();
+		mem += overlay.journal.heap_size_of_children();
+		mem
+	}
+
+	fn is_empty(&self) -> bool {
+		self.backing.get(&LATEST_ERA_KEY).expect("Low level database error").is_none()
+	}
+
+	fn commit(&mut self, now: u64, id: &H256, end: Option<(u64, H256)>) -> Result<u32, UtilError> {
+		// record new commit's details.
+		trace!("commit: #{} ({}), end era: {:?}", now, id, end);
+		let mut journal_overlay = self.journal_overlay.write().unwrap();
+		let batch = DBTransaction::new();
+		{
+			let mut r = RlpStream::new_list(3);
+			let mut tx = self.transaction_overlay.drain();
+			let inserted_keys: Vec<_> = tx.iter().filter_map(|(k, &(_, c))| if c > 0 { Some(k.clone()) } else { None }).collect();
+			let removed_keys: Vec<_> = tx.iter().filter_map(|(k, &(_, c))| if c < 0 { Some(k.clone()) } else { None }).collect();
+			// Increase counter for each inserted key no matter if the block is canonical or not. 
+			let insertions = tx.drain().filter_map(|(k, (v, c))| if c > 0 { Some((k, v)) } else { None });
+			r.append(id);
+			r.begin_list(inserted_keys.len());
+			for (k, v) in insertions {
+				r.begin_list(2);
+				r.append(&k);
+				r.append(&v);
+				journal_overlay.backing_overlay.emplace(k, v);
+			}
+			r.append(&removed_keys);
+
+			let mut k = RlpStream::new_list(3);
+			let index = journal_overlay.journal.get(&now).map(|j| j.len()).unwrap_or(0);
+			k.append(&now);
+			k.append(&index);
+			k.append(&&PADDING[..]);
+			try!(batch.put(&k.drain(), r.as_raw()));
+			if now >= journal_overlay.latest_era {
+				try!(batch.put(&LATEST_ERA_KEY, &encode(&now)));
+				journal_overlay.latest_era = now;
+			}
+			journal_overlay.journal.entry(now).or_insert_with(Vec::new).push(JournalEntry { id: id.clone(), insertions: inserted_keys, deletions: removed_keys });
+		}
+
+		let journal_overlay = journal_overlay.deref_mut();
+		// apply old commits' details
+		if let Some((end_era, canon_id)) = end {
+			if let Some(ref mut records) = journal_overlay.journal.get_mut(&end_era) {
+				let mut canon_insertions: Vec<(H256, Bytes)> = Vec::new();
+				let mut canon_deletions: Vec<H256> = Vec::new();
+				let mut overlay_deletions: Vec<H256> = Vec::new();
+				let mut index = 0usize;
+				for mut journal in records.drain(..) {
+					//delete the record from the db
+					let mut r = RlpStream::new_list(3);
+					r.append(&end_era);
+					r.append(&index);
+					r.append(&&PADDING[..]);
+					try!(batch.delete(&r.drain()));
+					trace!("commit: Delete journal for time #{}.{}: {}, (canon was {}): +{} -{} entries", end_era, index, journal.id, canon_id, journal.insertions.len(), journal.deletions.len());
+					{
+						if canon_id == journal.id {
+							for h in &journal.insertions {
+								if let Some(&(ref d, rc)) = journal_overlay.backing_overlay.raw(h) {
+									if rc > 0 {
+										canon_insertions.push((h.clone(), d.clone())); //TODO: optimize this to avoid data copy
+									}
+								}
+							}
+							canon_deletions = journal.deletions;
+						}
+						overlay_deletions.append(&mut journal.insertions);
+					}
+					index += 1;
+				}
+				// apply canon inserts first
+				for (k, v) in canon_insertions {
+					try!(batch.put(&k, &v));
+				}
+				// update the overlay
+				for k in overlay_deletions {
+					journal_overlay.backing_overlay.kill(&k);
+				}
+				// apply canon deletions
+				for k in canon_deletions {
+					if !journal_overlay.backing_overlay.exists(&k) {
+						try!(batch.delete(&k));
+					}
+				}
+				journal_overlay.backing_overlay.purge();
+			}
+			journal_overlay.journal.remove(&end_era);
+		}
+		try!(self.backing.write(batch));
+		Ok(0)
+	}
+
+}
+
+impl HashDB for OverlayRecentDB {
+	fn keys(&self) -> HashMap<H256, i32> {
+		let mut ret: HashMap<H256, i32> = HashMap::new();
+		for (key, _) in self.backing.iter() {
+			let h = H256::from_slice(key.deref());
+			ret.insert(h, 1);
+		}
+
+		for (key, refs) in self.transaction_overlay.keys().into_iter() {
+			let refs = *ret.get(&key).unwrap_or(&0) + refs;
+			ret.insert(key, refs);
+		}
+		ret
+	}
+
+	fn lookup(&self, key: &H256) -> Option<&[u8]> {
+		let k = self.transaction_overlay.raw(key);
+		match k {
+			Some(&(ref d, rc)) if rc > 0 => Some(d),
+			_ => {
+				let v = self.journal_overlay.read().unwrap().backing_overlay.lookup(key).map(|v| v.to_vec());
+				match v {
+					Some(x) => {
+						Some(&self.transaction_overlay.denote(key, x).0)
+					}
+					_ => {
+						if let Some(x) = self.payload(key) {
+							Some(&self.transaction_overlay.denote(key, x).0)
+						}
+						else {
+							None
+						}
+					}
+				}
+			}
+		}
+	}
+
+	fn exists(&self, key: &H256) -> bool {
+		self.lookup(key).is_some()
+	}
+
+	fn insert(&mut self, value: &[u8]) -> H256 { 
+		self.transaction_overlay.insert(value)
+	}
+	fn emplace(&mut self, key: H256, value: Bytes) {
+		self.transaction_overlay.emplace(key, value); 
+	}
+	fn kill(&mut self, key: &H256) { 
+		self.transaction_overlay.kill(key); 
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use common::*;
+	use super::*;
+	use hashdb::*;
+	use log::init_log;
+	use journaldb::JournalDB;
+
+	#[test]
+	fn insert_same_in_fork() {
+		// history is 1
+		let mut jdb = OverlayRecentDB::new_temp();
+
+		let x = jdb.insert(b"X");
+		jdb.commit(1, &b"1".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(2, &b"2".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(3, &b"1002a".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(4, &b"1003a".sha3(), Some((2, b"2".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&x);
+		jdb.commit(3, &b"1002b".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		let x = jdb.insert(b"X");
+		jdb.commit(4, &b"1003b".sha3(), Some((2, b"2".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.commit(5, &b"1004a".sha3(), Some((3, b"1002a".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(6, &b"1005a".sha3(), Some((4, b"1003a".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		assert!(jdb.exists(&x));
+	}
+
+	#[test]
+	fn long_history() {
+		// history is 3
+		let mut jdb = OverlayRecentDB::new_temp();
+		let h = jdb.insert(b"foo");
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&h));
+		jdb.remove(&h);
+		jdb.commit(1, &b"1".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&h));
+		jdb.commit(2, &b"2".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&h));
+		jdb.commit(3, &b"3".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&h));
+		jdb.commit(4, &b"4".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(!jdb.exists(&h));
+	}
+
+	#[test]
+	fn complex() {
+		// history is 1
+		let mut jdb = OverlayRecentDB::new_temp();
+
+		let foo = jdb.insert(b"foo");
+		let bar = jdb.insert(b"bar");
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+		assert!(jdb.exists(&bar));
+
+		jdb.remove(&foo);
+		jdb.remove(&bar);
+		let baz = jdb.insert(b"baz");
+		jdb.commit(1, &b"1".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+		assert!(jdb.exists(&bar));
+		assert!(jdb.exists(&baz));
+
+		let foo = jdb.insert(b"foo");
+		jdb.remove(&baz);
+		jdb.commit(2, &b"2".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+		assert!(!jdb.exists(&bar));
+		assert!(jdb.exists(&baz));
+
+		jdb.remove(&foo);
+		jdb.commit(3, &b"3".sha3(), Some((2, b"2".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+		assert!(!jdb.exists(&bar));
+		assert!(!jdb.exists(&baz));
+
+		jdb.commit(4, &b"4".sha3(), Some((3, b"3".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(!jdb.exists(&foo));
+		assert!(!jdb.exists(&bar));
+		assert!(!jdb.exists(&baz));
+	}
+
+	#[test]
+	fn fork() {
+		// history is 1
+		let mut jdb = OverlayRecentDB::new_temp();
+
+		let foo = jdb.insert(b"foo");
+		let bar = jdb.insert(b"bar");
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+		assert!(jdb.exists(&bar));
+
+		jdb.remove(&foo);
+		let baz = jdb.insert(b"baz");
+		jdb.commit(1, &b"1a".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&bar);
+		jdb.commit(1, &b"1b".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		assert!(jdb.exists(&foo));
+		assert!(jdb.exists(&bar));
+		assert!(jdb.exists(&baz));
+
+		jdb.commit(2, &b"2b".sha3(), Some((1, b"1b".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+		assert!(!jdb.exists(&baz));
+		assert!(!jdb.exists(&bar));
+	}
+
+	#[test]
+	fn overwrite() {
+		// history is 1
+		let mut jdb = OverlayRecentDB::new_temp();
+
+		let foo = jdb.insert(b"foo");
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+
+		jdb.remove(&foo);
+		jdb.commit(1, &b"1".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.insert(b"foo");
+		assert!(jdb.exists(&foo));
+		jdb.commit(2, &b"2".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+		jdb.commit(3, &b"2".sha3(), Some((0, b"2".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+	}
+
+	#[test]
+	fn fork_same_key_one() {
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		let foo = jdb.insert(b"foo");
+		jdb.commit(1, &b"1a".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(1, &b"1b".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(1, &b"1c".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		assert!(jdb.exists(&foo));
+
+		jdb.commit(2, &b"2a".sha3(), Some((1, b"1a".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+	}
+
+	#[test]
+	fn fork_same_key_other() {
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		let foo = jdb.insert(b"foo");
+		jdb.commit(1, &b"1a".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(1, &b"1b".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(1, &b"1c".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		assert!(jdb.exists(&foo));
+
+		jdb.commit(2, &b"2b".sha3(), Some((1, b"1b".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+	}
+
+	#[test]
+	fn fork_ins_del_ins() {
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		let foo = jdb.insert(b"foo");
+		jdb.commit(1, &b"1".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&foo);
+		jdb.commit(2, &b"2a".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&foo);
+		jdb.commit(2, &b"2b".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(3, &b"3a".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(3, &b"3b".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.commit(4, &b"4a".sha3(), Some((2, b"2a".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.commit(5, &b"5a".sha3(), Some((3, b"3a".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+	}
+
+	#[test]
+	fn reopen() {
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+		let bar = H256::random();
+
+		let foo = {
+			let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+			// history is 1
+			let foo = jdb.insert(b"foo");
+			jdb.emplace(bar.clone(), b"bar".to_vec());
+			jdb.commit(0, &b"0".sha3(), None).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			foo
+		};
+
+		{
+			let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+			jdb.remove(&foo);
+			jdb.commit(1, &b"1".sha3(), Some((0, b"0".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+		}
+
+		{
+			let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+			assert!(jdb.exists(&foo));
+			assert!(jdb.exists(&bar));
+			jdb.commit(2, &b"2".sha3(), Some((1, b"1".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			assert!(!jdb.exists(&foo));
+		}
+	}
+
+	#[test]
+	fn insert_delete_insert_delete_insert_expunge() {
+		init_log();
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+
+		// history is 4
+		let foo = jdb.insert(b"foo");
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.remove(&foo);
+		jdb.commit(1, &b"1".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.insert(b"foo");
+		jdb.commit(2, &b"2".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.remove(&foo);
+		jdb.commit(3, &b"3".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.insert(b"foo");
+		jdb.commit(4, &b"4".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		// expunge foo
+		jdb.commit(5, &b"5".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+	}
+
+	#[test]
+	fn forked_insert_delete_insert_delete_insert_expunge() {
+		init_log();
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+
+		// history is 4
+		let foo = jdb.insert(b"foo");
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&foo);
+		jdb.commit(1, &b"1a".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&foo);
+		jdb.commit(1, &b"1b".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(2, &b"2a".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(2, &b"2b".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&foo);
+		jdb.commit(3, &b"3a".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.remove(&foo);
+		jdb.commit(3, &b"3b".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(4, &b"4a".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(4, &b"4b".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		// expunge foo
+		jdb.commit(5, &b"5".sha3(), Some((1, b"1a".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+	}
+
+	#[test]
+	fn broken_assert() {
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+		// history is 1
+		let foo = jdb.insert(b"foo");
+		jdb.commit(1, &b"1".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		// foo is ancient history.
+
+		jdb.remove(&foo);
+		jdb.commit(2, &b"2".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.insert(b"foo");
+		jdb.commit(3, &b"3".sha3(), Some((2, b"2".sha3()))).unwrap();	// BROKEN
+		assert!(jdb.can_reconstruct_refs());
+		assert!(jdb.exists(&foo));
+
+		jdb.remove(&foo);
+		jdb.commit(4, &b"4".sha3(), Some((3, b"3".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		jdb.commit(5, &b"5".sha3(), Some((4, b"4".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		assert!(!jdb.exists(&foo));
+	}
+	
+	#[test]
+	fn reopen_test() {
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+		// history is 4
+		let foo = jdb.insert(b"foo");
+		jdb.commit(0, &b"0".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(1, &b"1".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(2, &b"2".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(3, &b"3".sha3(), None).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.commit(4, &b"4".sha3(), Some((0, b"0".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+
+		// foo is ancient history.
+
+		jdb.insert(b"foo");
+		let bar = jdb.insert(b"bar");
+		jdb.commit(5, &b"5".sha3(), Some((1, b"1".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.remove(&foo);
+		jdb.remove(&bar);
+		jdb.commit(6, &b"6".sha3(), Some((2, b"2".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+		jdb.insert(b"foo");
+		jdb.insert(b"bar");
+		jdb.commit(7, &b"7".sha3(), Some((3, b"3".sha3()))).unwrap();
+		assert!(jdb.can_reconstruct_refs());
+	}
+	
+	#[test]
+	fn reopen_remove_three() {
+		init_log();
+
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+
+		let foo = b"foo".sha3();
+
+		{
+			let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+			// history is 1
+			jdb.insert(b"foo");
+			jdb.commit(0, &b"0".sha3(), None).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			jdb.commit(1, &b"1".sha3(), None).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+
+			// foo is ancient history.
+
+			jdb.remove(&foo);
+			jdb.commit(2, &b"2".sha3(), Some((0, b"0".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			assert!(jdb.exists(&foo));
+
+			jdb.insert(b"foo");
+			jdb.commit(3, &b"3".sha3(), Some((1, b"1".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			assert!(jdb.exists(&foo));
+
+		// incantation to reopen the db
+		}; { let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+
+			jdb.remove(&foo);
+			jdb.commit(4, &b"4".sha3(), Some((2, b"2".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			assert!(jdb.exists(&foo));
+
+		// incantation to reopen the db
+		}; { let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+
+			jdb.commit(5, &b"5".sha3(), Some((3, b"3".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			assert!(jdb.exists(&foo));
+
+		// incantation to reopen the db
+		}; { let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+
+			jdb.commit(6, &b"6".sha3(), Some((4, b"4".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			assert!(!jdb.exists(&foo));
+		}
+	}
+	
+	#[test]
+	fn reopen_fork() {
+		let mut dir = ::std::env::temp_dir();
+		dir.push(H32::random().hex());
+		let (foo, bar, baz) = {
+			let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+			// history is 1
+			let foo = jdb.insert(b"foo");
+			let bar = jdb.insert(b"bar");
+			jdb.commit(0, &b"0".sha3(), None).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			jdb.remove(&foo);
+			let baz = jdb.insert(b"baz");
+			jdb.commit(1, &b"1a".sha3(), Some((0, b"0".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+
+			jdb.remove(&bar);
+			jdb.commit(1, &b"1b".sha3(), Some((0, b"0".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			(foo, bar, baz)
+		};
+
+		{
+			let mut jdb = OverlayRecentDB::new(dir.to_str().unwrap());
+			jdb.commit(2, &b"2b".sha3(), Some((1, b"1b".sha3()))).unwrap();
+			assert!(jdb.can_reconstruct_refs());
+			assert!(jdb.exists(&foo));
+			assert!(!jdb.exists(&baz));
+			assert!(!jdb.exists(&bar));
+		}
+	}
+}

util/src/keys/store.rs

@@ -131,9 +131,15 @@ impl AccountService {
 	}
 }
 
+impl Default for SecretStore {
+	fn default() -> Self {
+		SecretStore::new()
+	}
+}
+
 impl SecretStore {
 	/// new instance of Secret Store in default home directory
-	pub fn new() -> SecretStore {
+	pub fn new() -> Self {
 		let mut path = ::std::env::home_dir().expect("Failed to get home dir");
 		path.push(".parity");
 		path.push("keys");
@@ -142,7 +148,7 @@ impl SecretStore {
 	}
 
 	/// new instance of Secret Store in specific directory
-	pub fn new_in(path: &Path) -> SecretStore {
+	pub fn new_in(path: &Path) -> Self {
 		SecretStore {
 			directory: KeyDirectory::new(path),
 			unlocks: RwLock::new(HashMap::new()),
@@ -214,12 +220,12 @@ impl SecretStore {
 
 	/// Creates new account
 	pub fn new_account(&mut self, pass: &str) -> Result<Address, ::std::io::Error> {
-		let secret = H256::random();
+		let key_pair = crypto::KeyPair::create().expect("Error creating key-pair. Something wrong with crypto libraries?");
+		let address = Address::from(key_pair.public().sha3());
 		let key_id = H128::random();
-		self.insert(key_id.clone(), secret, pass);
+		self.insert(key_id.clone(), key_pair.secret().clone(), pass);
 
 		let mut key_file = self.directory.get(&key_id).expect("the key was just inserted");
-		let address = Address::random();
 		key_file.account = Some(address);
 		try!(self.directory.save(key_file));
 		Ok(address)
@@ -381,6 +387,7 @@ mod tests {
 	use super::*;
 	use devtools::*;
 	use common::*;
+	use crypto::KeyPair;
 
 	#[test]
 	fn can_insert() {
@@ -555,4 +562,15 @@ mod tests {
 		let accounts = sstore.accounts().unwrap();
 		assert_eq!(30, accounts.len());
 	}
+
+	#[test]
+	fn validate_generated_addresses() {
+		let temp = RandomTempPath::create_dir();
+		let mut sstore = SecretStore::new_test(&temp);
+		let addr = sstore.new_account("test").unwrap();
+		let _ok = sstore.unlock_account(&addr, "test").unwrap();
+		let secret = sstore.account_secret(&addr).unwrap();
+		let kp = KeyPair::from_secret(secret).unwrap();
+		assert_eq!(Address::from(kp.public().sha3()), addr);
+	}
 }

util/src/kvdb.rs

@@ -16,6 +16,7 @@
 
 //! Key-Value store abstraction with RocksDB backend.
 
+use std::default::Default;
 use rocksdb::{DB, Writable, WriteBatch, IteratorMode, DBVector, DBIterator,
 	IndexType, Options, DBCompactionStyle, BlockBasedOptions, Direction};
 
@@ -24,6 +25,12 @@ pub struct DBTransaction {
 	batch: WriteBatch,
 }
 
+impl Default for DBTransaction {
+	fn default() -> Self {
+		DBTransaction::new()
+	}
+}
+
 impl DBTransaction {
 	/// Create new transaction.
 	pub fn new() -> DBTransaction {

util/src/lib.rs

@@ -27,6 +27,8 @@
 #![cfg_attr(feature="dev", allow(match_same_arms))]
 // Keeps consistency (all lines with `.clone()`) and helpful when changing ref to non-ref.
 #![cfg_attr(feature="dev", allow(clone_on_copy))]
+// In most cases it expresses function flow better
+#![cfg_attr(feature="dev", allow(if_not_else))]
 
 //! Ethcore-util library
 //!

util/src/memorydb.rs

@@ -24,6 +24,7 @@ use hashdb::*;
 use heapsize::*;
 use std::mem;
 use std::collections::HashMap;
+use std::default::Default;
 
 #[derive(Debug,Clone)]
 /// Reference-counted memory-based HashDB implementation.
@@ -32,7 +33,7 @@ use std::collections::HashMap;
 /// with `kill()`, check for existance with `exists()` and lookup a hash to derive
 /// the data with `lookup()`. Clear with `clear()` and purge the portions of the data
 /// that have no references with `purge()`.
-/// 
+///
 /// # Example
 /// ```rust
 /// extern crate ethcore_util;
@@ -69,11 +70,18 @@ use std::collections::HashMap;
 ///   assert!(!m.exists(&k));
 /// }
 /// ```
+#[derive(PartialEq)]
 pub struct MemoryDB {
 	data: HashMap<H256, (Bytes, i32)>,
 	static_null_rlp: (Bytes, i32),
 }
 
+impl Default for MemoryDB {
+	fn default() -> Self {
+		MemoryDB::new()
+	}
+}
+
 impl MemoryDB {
 	/// Create a new instance of the memory DB.
 	pub fn new() -> MemoryDB {
@@ -133,7 +141,7 @@ impl MemoryDB {
 
 	/// Denote than an existing value has the given key. Used when a key gets removed without
 	/// a prior insert and thus has a negative reference with no value.
-	/// 
+	///
 	/// May safely be called even if the key's value is known, in which case it will be a no-op.
 	pub fn denote(&self, key: &H256, value: Bytes) -> &(Bytes, i32) {
 		if self.raw(key) == None {

util/src/network/discovery.rs

@@ -19,6 +19,7 @@ use std::net::SocketAddr;
 use std::collections::{HashSet, HashMap, BTreeMap, VecDeque};
 use std::mem;
 use std::cmp;
+use std::default::Default;
 use mio::*;
 use mio::udp::*;
 use sha3::*;
@@ -62,8 +63,14 @@ struct NodeBucket {
 	nodes: VecDeque<BucketEntry>, //sorted by last active
 }
 
+impl Default for NodeBucket {
+	fn default() -> Self {
+		NodeBucket::new()
+	}
+}
+
 impl NodeBucket {
-	fn new() -> NodeBucket {
+	fn new() -> Self {
 		NodeBucket {
 			nodes: VecDeque::new()
 		}

util/src/network/host.rs

@@ -23,6 +23,7 @@ use std::ops::*;
 use std::cmp::min;
 use std::path::{Path, PathBuf};
 use std::io::{Read, Write};
+use std::default::Default;
 use std::fs;
 use mio::*;
 use mio::tcp::*;
@@ -75,9 +76,15 @@ pub struct NetworkConfiguration {
 	pub ideal_peers: u32,
 }
 
+impl Default for NetworkConfiguration {
+	fn default() -> Self {
+		NetworkConfiguration::new()
+	}
+}
+
 impl NetworkConfiguration {
 	/// Create a new instance of default settings.
-	pub fn new() -> NetworkConfiguration {
+	pub fn new() -> Self {
 		NetworkConfiguration {
 			config_path: None,
 			listen_address: None,

util/src/panics.rs

@@ -19,6 +19,7 @@
 use std::thread;
 use std::ops::DerefMut;
 use std::sync::{Arc, Mutex};
+use std::default::Default;
 
 /// Thread-safe closure for handling possible panics
 pub trait OnPanicListener: Send + Sync + 'static {
@@ -56,14 +57,20 @@ pub struct PanicHandler {
 	listeners: Mutex<Vec<Box<OnPanicListener>>>
 }
 
+impl Default for PanicHandler {
+	fn default() -> Self {
+		PanicHandler::new()
+	}
+}
+
 impl PanicHandler {
 	/// Creates new `PanicHandler` wrapped in `Arc`
-	pub fn new_in_arc() -> Arc<PanicHandler> {
+	pub fn new_in_arc() -> Arc<Self> {
 		Arc::new(Self::new())
 	}
 
 	/// Creates new `PanicHandler`
-	pub fn new() -> PanicHandler {
+	pub fn new() -> Self {
 		PanicHandler {
 			listeners: Mutex::new(vec![])
 		}

util/src/rlp/rlpstream.rs

@@ -15,6 +15,7 @@
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
 use std::ops::Deref;
+use std::default::Default;
 use elastic_array::*;
 use rlp::bytes::{ToBytes, VecLike};
 use rlp::{Stream, Encoder, Encodable};
@@ -44,6 +45,12 @@ pub struct RlpStream {
 	finished_list: bool,
 }
 
+impl Default  for RlpStream {
+	fn default() -> Self {
+		RlpStream::new()
+	}
+}
+
 impl Stream for RlpStream {
 	fn new() -> Self {
 		RlpStream {
@@ -190,8 +197,14 @@ struct BasicEncoder {
 	bytes: ElasticArray1024<u8>,
 }
 
+impl Default for BasicEncoder {
+	fn default() -> Self {
+		BasicEncoder::new()
+	}
+}
+
 impl BasicEncoder {
-	fn new() -> BasicEncoder {
+	fn new() -> Self {
 		BasicEncoder { bytes: ElasticArray1024::new() }
 	}
 
@@ -222,7 +235,7 @@ impl Encoder for BasicEncoder {
 			// just 0
 			0 => self.bytes.push(0x80u8),
 			// byte is its own encoding if < 0x80
-			1 => { 
+			1 => {
 				value.to_bytes(&mut self.bytes);
 				let len = self.bytes.len();
 				let last_byte = self.bytes[len - 1];

util/src/table.rs

@@ -16,6 +16,7 @@
 
 //! A collection associating pair of keys (row and column) with a single value.
 
+use std::default::Default;
 use std::hash::Hash;
 use std::collections::HashMap;
 
@@ -30,11 +31,21 @@ pub struct Table<Row, Col, Val>
 	map: HashMap<Row, HashMap<Col, Val>>,
 }
 
+impl<Row, Col, Val> Default for Table<Row, Col, Val>
+	where Row: Eq + Hash + Clone,
+		  Col: Eq + Hash {
+	fn default() -> Self {
+		Table::new()
+	}
+}
+
+// There is default but clippy does not detect it?
+#[allow(new_without_default)]
 impl<Row, Col, Val> Table<Row, Col, Val>
 	where Row: Eq + Hash + Clone,
 		  Col: Eq + Hash {
 	/// Creates new Table
-	pub fn new() -> Table<Row, Col, Val> {
+	pub fn new() -> Self {
 		Table {
 			map: HashMap::new(),
 		}

util/src/trie/journal.rs

@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
+use std::default::Default;
 use sha3::*;
 use hash::H256;
 use bytes::*;
@@ -39,6 +40,12 @@ pub struct Score {
 #[derive(Debug)]
 pub struct Journal (Vec<Operation>);
 
+impl Default for Journal {
+	fn default() -> Self {
+		Journal::new()
+	}
+}
+
 impl Journal {
 	/// Create a new, empty, object.
 	pub fn new() -> Journal { Journal(vec![]) }