1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 // This file contains the implementation of the command parser.
6
7 #include "gpu/command_buffer/service/cmd_parser.h"
8
9 #include "base/logging.h"
10 #include "base/debug/trace_event.h"
11
12 namespace gpu {
13
CommandParser(AsyncAPIInterface * handler)14 CommandParser::CommandParser(AsyncAPIInterface* handler)
15 : get_(0),
16 put_(0),
17 buffer_(NULL),
18 entry_count_(0),
19 handler_(handler) {
20 }
21
SetBuffer(void * shm_address,size_t shm_size,ptrdiff_t offset,size_t size)22 void CommandParser::SetBuffer(
23 void* shm_address,
24 size_t shm_size,
25 ptrdiff_t offset,
26 size_t size) {
27 // check proper alignments.
28 DCHECK_EQ(0, (reinterpret_cast<intptr_t>(shm_address)) % 4);
29 DCHECK_EQ(0, offset % 4);
30 DCHECK_EQ(0u, size % 4);
31 // check that the command buffer fits into the memory buffer.
32 DCHECK_GE(shm_size, offset + size);
33 get_ = 0;
34 put_ = 0;
35 char* buffer_begin = static_cast<char*>(shm_address) + offset;
36 buffer_ = reinterpret_cast<CommandBufferEntry*>(buffer_begin);
37 entry_count_ = size / 4;
38 }
39
40 // Process one command, reading the header from the command buffer, and
41 // forwarding the command index and the arguments to the handler.
42 // Note that:
43 // - validation needs to happen on a copy of the data (to avoid race
44 // conditions). This function only validates the header, leaving the arguments
45 // validation to the handler, so it can pass a reference to them.
46 // - get_ is modified *after* the command has been executed.
ProcessCommand()47 error::Error CommandParser::ProcessCommand() {
48 CommandBufferOffset get = get_;
49 if (get == put_)
50 return error::kNoError;
51
52 CommandHeader header = buffer_[get].value_header;
53 if (header.size == 0) {
54 DVLOG(1) << "Error: zero sized command in command buffer";
55 return error::kInvalidSize;
56 }
57
58 if (static_cast<int>(header.size) + get > entry_count_) {
59 DVLOG(1) << "Error: get offset out of bounds";
60 return error::kOutOfBounds;
61 }
62
63 TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cb_command"),
64 handler_->GetCommandName(header.command));
65
66 error::Error result = handler_->DoCommand(
67 header.command, header.size - 1, buffer_ + get);
68
69 // TODO(gman): If you want to log errors this is the best place to catch them.
70 // It seems like we need an official way to turn on a debug mode and
71 // get these errors.
72 if (error::IsError(result)) {
73 ReportError(header.command, result);
74 }
75
76 // If get was not set somewhere else advance it.
77 if (get == get_ && result != error::kDeferCommandUntilLater)
78 get_ = (get + header.size) % entry_count_;
79
80 return result;
81 }
82
ReportError(unsigned int command_id,error::Error result)83 void CommandParser::ReportError(unsigned int command_id,
84 error::Error result) {
85 DVLOG(1) << "Error: " << result << " for Command "
86 << handler_->GetCommandName(command_id);
87 }
88
89 // Processes all the commands, while the buffer is not empty. Stop if an error
90 // is encountered.
ProcessAllCommands()91 error::Error CommandParser::ProcessAllCommands() {
92 while (!IsEmpty()) {
93 error::Error error = ProcessCommand();
94 if (error)
95 return error;
96 }
97 return error::kNoError;
98 }
99
100 } // namespace gpu
101