51 lines
1.8 KiB
Rust
51 lines
1.8 KiB
Rust
// Copyright 2015-2017 Parity Technologies (UK) Ltd.
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// This file is part of Parity.
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// Parity is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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// Parity is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License
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// along with Parity. If not, see <http://www.gnu.org/licenses/>.
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//! Wasm evm results helper
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use byteorder::{LittleEndian, ByteOrder};
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use parity_wasm::interpreter;
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use super::ptr::WasmPtr;
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use super::runtime::Error as RuntimeError;
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/// Wrapper for wasm contract call result
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pub struct WasmResult {
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ptr: WasmPtr,
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}
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impl WasmResult {
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/// New call result from given ptr
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pub fn new(descriptor_ptr: WasmPtr) -> WasmResult {
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WasmResult { ptr: descriptor_ptr }
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}
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/// Check if the result contains any data
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pub fn peek_empty(&self, mem: &interpreter::MemoryInstance) -> Result<bool, RuntimeError> {
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let result_len = LittleEndian::read_u32(&self.ptr.slice(16, mem)?[12..16]);
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Ok(result_len == 0)
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}
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/// Consume the result ptr and return the actual data from wasm linear memory
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pub fn pop(self, mem: &interpreter::MemoryInstance) -> Result<Vec<u8>, RuntimeError> {
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let result_ptr = LittleEndian::read_u32(&self.ptr.slice(16, mem)?[8..12]);
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let result_len = LittleEndian::read_u32(&self.ptr.slice(16, mem)?[12..16]);
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trace!(target: "wasm", "contract result: {} bytes at @{}", result_len, result_ptr);
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Ok(mem.get(result_ptr, result_len as usize)?)
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}
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} |