From a3073f6189b34da5d4e8bc71cb7f1b3882dde154 Mon Sep 17 00:00:00 2001
From: lash <dev@holbrook.no>
Date: Thu, 6 Apr 2023 10:08:40 +0100
Subject: [PATCH] WIP Add termination handler in engine

---
 go/asm/asm.go            |  1 -
 go/dev/interactive.go    |  3 ++-
 go/engine/engine.go      | 26 +++++++++++++++++++++-----
 go/engine/engine_test.go |  2 +-
 go/state/state.go        | 20 ++++++++++++++++++++
 go/vm/runner.go          |  6 +++---
 go/vm/vm.go              | 17 -----------------
 7 files changed, 47 insertions(+), 28 deletions(-)

diff --git a/go/asm/asm.go b/go/asm/asm.go
index c3b5011..40ba8b2 100644
--- a/go/asm/asm.go
+++ b/go/asm/asm.go
@@ -321,7 +321,6 @@ func(bt *Batcher) MenuExit(w io.Writer) (int, error) {
 	}
 	bt.inMenu = false
 	b := bt.menuProcessor.ToLines()
-	log.Printf("tolines %v", b)
 	return w.Write(b)
 }
 
diff --git a/go/dev/interactive.go b/go/dev/interactive.go
index d8657ba..8332c18 100644
--- a/go/dev/interactive.go
+++ b/go/dev/interactive.go
@@ -41,7 +41,7 @@ func main() {
 			os.Exit(1)
 		}
 		in = strings.TrimSpace(in)
-		err = en.Exec([]byte(in), ctx)
+		running, err = en.Exec([]byte(in), ctx)
 		if err != nil {
 			fmt.Fprintf(os.Stderr, "execution terminated: %v\n", err)
 			os.Exit(1)
@@ -50,4 +50,5 @@ func main() {
 		en.WriteResult(b)
 		fmt.Println(b.String())
 	}
+
 }
diff --git a/go/engine/engine.go b/go/engine/engine.go
index 344aac9..4937fb3 100644
--- a/go/engine/engine.go
+++ b/go/engine/engine.go
@@ -59,22 +59,38 @@ func(en *Engine) Init(sym string, ctx context.Context) error {
 // - input is objectively invalid (too long etc)
 // - no current bytecode is available
 // - input processing against bytcode failed
-func (en *Engine) Exec(input []byte, ctx context.Context) error {
+func (en *Engine) Exec(input []byte, ctx context.Context) (bool, error) {
 	err := en.st.SetInput(input)
 	if err != nil {
-		return err
+		return false, err
 	}
 	log.Printf("new execution with input '%s' (0x%x)", input, input)
 	code, err := en.st.GetCode()
 	if err != nil {
-		return err
+		return false, err
 	}
 	if len(code) == 0 {
-		return fmt.Errorf("no code to execute")
+		return false, fmt.Errorf("no code to execute")
 	}
 	code, err = vm.Run(code, en.st, en.rs, ctx)
+	if err != nil {
+		return false, err
+	}
+
+	v, err := en.st.MatchFlag(state.FLAG_TERMINATE, false)
+	if err != nil {
+		return false, err
+	}
+	if v {
+		if len(code) > 0 {
+			log.Printf("terminated with code remaining: %x", code)
+		}
+		return false, nil
+	}
+
 	en.st.SetCode(code)
-	return err
+
+	return true, nil
 }
 
 // WriteResult writes the output of the last vm execution to the given writer.
diff --git a/go/engine/engine_test.go b/go/engine/engine_test.go
index 06d4fb1..61a1820 100644
--- a/go/engine/engine_test.go
+++ b/go/engine/engine_test.go
@@ -97,7 +97,7 @@ func TestEngineInit(t *testing.T) {
 	}
 
 	input := []byte("1")
-	err = en.Exec(input, ctx)
+	_, err = en.Exec(input, ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/go/state/state.go b/go/state/state.go
index 2428a65..835aa67 100644
--- a/go/state/state.go
+++ b/go/state/state.go
@@ -135,6 +135,26 @@ func(st *State) FlagByteSize() uint8 {
 	return uint8(len(st.Flags))
 }
 
+// MatchFlag matches the current state of the given flag.
+//
+// The flag is specified given its bit index in the bit field.
+//
+// If invertMatch is set, a positive result will be returned if the flag is not set.
+func(st *State) MatchFlag(sig uint32, invertMatch bool) (bool, error) {
+	r, err := st.GetFlag(sig)
+	if err != nil {
+		return false, err
+	}
+	if invertMatch {
+		if !r {
+			return true, nil
+		}
+	} else if r {
+		return true, nil
+	}
+	return false, nil
+}
+
 // GetIndex scans a byte slice in same order as in storage, and returns the index of the first set bit.
 //
 // If the given byte slice is too small for the bit field bitsize, the check will terminate at end-of-data without error.
diff --git a/go/vm/runner.go b/go/vm/runner.go
index 8bab0dc..a15df30 100644
--- a/go/vm/runner.go
+++ b/go/vm/runner.go
@@ -82,7 +82,7 @@ func RunDeadCheck(b []byte, st *state.State, rs resource.Resource, ctx context.C
 		return b, nil
 	}
 	log.Printf("no code remaining, let's check if we terminate")
-	r, err := matchFlag(st, state.FLAG_TERMINATE, false)
+	r, err := st.MatchFlag(state.FLAG_TERMINATE, false)
 	if err != nil {
 		panic(err)
 	}
@@ -114,7 +114,7 @@ func RunCatch(b []byte, st *state.State, rs resource.Resource, ctx context.Conte
 	if err != nil {
 		return b, err
 	}
-	r, err := matchFlag(st, sig, mode)
+	r, err := st.MatchFlag(sig, mode)
 	if err != nil {
 		return b, err
 	}
@@ -132,7 +132,7 @@ func RunCroak(b []byte, st *state.State, rs resource.Resource, ctx context.Conte
 	if err != nil {
 		return b, err
 	}
-	r, err := matchFlag(st, sig, mode)
+	r, err := st.MatchFlag(sig, mode)
 	if err != nil {
 		return b, err
 	}
diff --git a/go/vm/vm.go b/go/vm/vm.go
index 3491a6a..130a294 100644
--- a/go/vm/vm.go
+++ b/go/vm/vm.go
@@ -3,8 +3,6 @@ package vm
 import (
 	"encoding/binary"
 	"fmt"
-
-	"git.defalsify.org/festive/state"
 )
 
 // NewLine creates a new instruction line for the VM.
@@ -177,21 +175,6 @@ func parseSig(b []byte) (uint32, bool, []byte, error) {
 	return sig, matchmode, b, nil
 }
 
-// TODO: move to state
-func matchFlag(st *state.State, sig uint32, invertMatch bool) (bool, error) {
-	r, err := st.GetFlag(sig)
-	if err != nil {
-		return false, err
-	}
-	if invertMatch {
-		if !r {
-			return true, nil
-		}
-	} else if r {
-		return true, nil
-	}
-	return false, nil
-}
 
 // split bytecode into head and b using length-prefixed bitfield
 func byteSplit(b []byte) ([]byte, []byte, error) {