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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This file contains the implementation of the command parser.
#include "gpu/command_buffer/service/cmd_parser.h"
#include "base/logging.h"
namespace gpu {
CommandParser::CommandParser(void *shm_address,
size_t shm_size,
ptrdiff_t offset,
size_t size,
CommandBufferOffset start_get,
AsyncAPIInterface *handler)
: get_(start_get),
put_(start_get),
handler_(handler) {
// check proper alignments.
DCHECK_EQ(0, (reinterpret_cast<intptr_t>(shm_address)) % 4);
DCHECK_EQ(0, offset % 4);
DCHECK_EQ(0u, size % 4);
// check that the command buffer fits into the memory buffer.
DCHECK_GE(shm_size, offset + size);
char * buffer_begin = static_cast<char *>(shm_address) + offset;
buffer_ = reinterpret_cast<CommandBufferEntry *>(buffer_begin);
entry_count_ = size / 4;
}
// Process one command, reading the header from the command buffer, and
// forwarding the command index and the arguments to the handler.
// Note that:
// - validation needs to happen on a copy of the data (to avoid race
// conditions). This function only validates the header, leaving the arguments
// validation to the handler, so it can pass a reference to them.
// - get_ is modified *after* the command has been executed.
error::Error CommandParser::ProcessCommand() {
CommandBufferOffset get = get_;
if (get == put_)
return error::kNoError;
CommandHeader header = buffer_[get].value_header;
if (header.size == 0) {
DVLOG(1) << "Error: zero sized command in command buffer";
return error::kInvalidSize;
}
if (static_cast<int>(header.size) + get > entry_count_) {
DVLOG(1) << "Error: get offset out of bounds";
return error::kOutOfBounds;
}
error::Error result = handler_->DoCommand(
header.command, header.size - 1, buffer_ + get);
// TODO(gman): If you want to log errors this is the best place to catch them.
// It seems like we need an official way to turn on a debug mode and
// get these errors.
if (error::IsError(result)) {
ReportError(header.command, result);
}
// If get was not set somewhere else advance it.
if (result != error::kWaiting && get == get_)
get_ = (get + header.size) % entry_count_;
return result;
}
void CommandParser::ReportError(unsigned int command_id,
error::Error result) {
DVLOG(1) << "Error: " << result << " for Command "
<< handler_->GetCommandName(command_id);
}
// Processes all the commands, while the buffer is not empty. Stop if an error
// is encountered.
error::Error CommandParser::ProcessAllCommands() {
while (!IsEmpty()) {
error::Error error = ProcessCommand();
if (error)
return error;
}
return error::kNoError;
}
} // namespace gpu
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