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117 lines
3.7 KiB
C++
117 lines
3.7 KiB
C++
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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// This file contains the implementation of the command parser.
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#include "gpu/command_buffer/service/cmd_parser.h"
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#include "base/logging.h"
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#include "base/trace_event/trace_event.h"
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namespace gpu {
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CommandParser::CommandParser(AsyncAPIInterface* handler)
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: get_(0),
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put_(0),
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buffer_(NULL),
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entry_count_(0),
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handler_(handler) {
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}
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void CommandParser::SetBuffer(
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void* shm_address,
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size_t shm_size,
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ptrdiff_t offset,
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size_t size) {
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// check proper alignments.
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DCHECK_EQ(0, (reinterpret_cast<intptr_t>(shm_address)) % 4);
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DCHECK_EQ(0, offset % 4);
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DCHECK_EQ(0u, size % 4);
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// check that the command buffer fits into the memory buffer.
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DCHECK_GE(shm_size, offset + size);
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get_ = 0;
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put_ = 0;
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char* buffer_begin = static_cast<char*>(shm_address) + offset;
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buffer_ = reinterpret_cast<CommandBufferEntry*>(buffer_begin);
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entry_count_ = size / 4;
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}
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// Process one command, reading the header from the command buffer, and
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// forwarding the command index and the arguments to the handler.
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// Note that:
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// - validation needs to happen on a copy of the data (to avoid race
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// conditions). This function only validates the header, leaving the arguments
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// validation to the handler, so it can pass a reference to them.
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// - get_ is modified *after* the command has been executed.
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error::Error CommandParser::ProcessCommands(int num_commands) {
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int num_entries = put_ < get_ ? entry_count_ - get_ : put_ - get_;
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int entries_processed = 0;
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error::Error result = handler_->DoCommands(
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num_commands, buffer_ + get_, num_entries, &entries_processed);
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get_ += entries_processed;
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if (get_ == entry_count_)
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get_ = 0;
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return result;
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}
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// Processes all the commands, while the buffer is not empty. Stop if an error
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// is encountered.
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error::Error CommandParser::ProcessAllCommands() {
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while (!IsEmpty()) {
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error::Error error = ProcessCommands(kParseCommandsSlice);
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if (error)
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return error;
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}
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return error::kNoError;
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}
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// Decode multiple commands, and call the corresponding GL functions.
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// NOTE: buffer is a pointer to the command buffer. As such, it could be
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// changed by a (malicious) client at any time, so if validation has to happen,
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// it should operate on a copy of them.
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error::Error AsyncAPIInterface::DoCommands(unsigned int num_commands,
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const void* buffer,
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int num_entries,
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int* entries_processed) {
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int commands_to_process = num_commands;
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error::Error result = error::kNoError;
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const CommandBufferEntry* cmd_data =
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static_cast<const CommandBufferEntry*>(buffer);
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int process_pos = 0;
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while (process_pos < num_entries && result == error::kNoError &&
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commands_to_process--) {
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CommandHeader header = cmd_data->value_header;
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if (header.size == 0) {
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DVLOG(1) << "Error: zero sized command in command buffer";
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return error::kInvalidSize;
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}
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if (static_cast<int>(header.size) + process_pos > num_entries) {
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DVLOG(1) << "Error: get offset out of bounds";
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return error::kOutOfBounds;
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}
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const unsigned int command = header.command;
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const unsigned int arg_count = header.size - 1;
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result = DoCommand(command, arg_count, cmd_data);
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if (result != error::kDeferCommandUntilLater) {
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process_pos += header.size;
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cmd_data += header.size;
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}
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}
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if (entries_processed)
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*entries_processed = process_pos;
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return result;
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}
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} // namespace gpu
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