Shared Raster Worker Threads

cc/base/switches.cc

 // Copyright (c) 2012 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.
 
 #include "cc/base/switches.h"
 
 #include "base/command_line.h"
+#include "base/strings/string_number_conversions.h"
 
 namespace cc {
 namespace switches {
 
 // On platforms where checkerboards are used, prefer background colors instead
 // of checkerboards.
 const char kBackgroundColorInsteadOfCheckerboard[] =
     "background-color-instead-of-checkerboard";
 
 // Disables LCD text.
@@ skipping 184 matching lines @@
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(switches::kDisableMapImage))
     return false;
   else if (command_line.HasSwitch(switches::kEnableMapImage))
     return true;
 
   return false;
 }
 
+size_t CheckNumRasterThreads() {

[reveman, 2013/12/27 14:57:13]

move this function to anonymous namespace.

[sohanjg, 2013/12/28 09:15:17]

Done.

+  const int kMinRasterThreads = 1;
+  const int kMaxRasterThreads = 64;
+  const int kDefaultNumRasterThreads = 1;
+
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  int num_threads = kDefaultNumRasterThreads;
+  if (command_line.HasSwitch(switches::kNumRasterThreads)) {
+    std::string string_value =
+        command_line.GetSwitchValueASCII(switches::kNumRasterThreads);
+    if (!(base::StringToInt(string_value, &num_threads) &&
+        num_threads >= kMinRasterThreads && num_threads <= kMaxRasterThreads)) {

[reveman, 2013/12/27 14:57:13]

This is wrong. You're checking the value of num_threads if base::StringToInt
fails. That doesn't make sense. You probably meant to do:
if (!(base::StringToInt(string_value, &num_threads) ||
    num_threads < kMinRasterThreads ||
    num_threads > kMaxRasterThreads)

Might be cleaner to do:
if (base::StringToInt(string_value, &num_threads) &&
    num_threads >= kMinRasterThreads &&
    num_threads <= kMaxRasterThreads)
  return num_threads;

LOG(WARNING) << ....

[sohanjg, 2013/12/28 09:15:17]

Done.

+      LOG(WARNING) << "Failed to parse switch " <<
+                      switches::kNumRasterThreads  << ": " << string_value;
+      num_threads = kDefaultNumRasterThreads;
+    }
+  }
+  return num_threads;
+}
+
+size_t GetNumRasterThreads() {
+  static size_t num_raster_threads = CheckNumRasterThreads();
+  return num_raster_threads;
+}
 }  // namespace switches
 }  // namespace cc