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/*
* Copyright 2009, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// This file contains the implementation of the command parser.
#include "command_buffer/service/cross/cmd_parser.h"
namespace o3d {
namespace command_buffer {
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.
parse_error::ParseError CommandParser::ProcessCommand() {
CommandBufferOffset get = get_;
if (get == put_) return parse_error::kParseNoError;
CommandHeader header = buffer_[get].value_header;
if (header.size == 0) {
DLOG(INFO) << "Error: zero sized command in command buffer";
return parse_error::kParseInvalidSize;
}
if (header.size + get > entry_count_) {
DLOG(INFO) << "Error: get offset out of bounds";
return parse_error::kParseOutOfBounds;
}
parse_error::ParseError 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 (result != parse_error::kParseNoError) {
DLOG(INFO) << "Error: " << result << " for Command "
<< GetCommandName(static_cast<CommandId>(header.command));
}
get_ = (get + header.size) % entry_count_;
return result;
}
// Processes all the commands, while the buffer is not empty. Stop if an error
// is encountered.
parse_error::ParseError CommandParser::ProcessAllCommands() {
while (!IsEmpty()) {
parse_error::ParseError error = ProcessCommand();
if (error) return error;
}
return parse_error::kParseNoError;
}
} // namespace command_buffer
} // namespace o3d
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