On Linux rework driver_version/vendor extraction from gl version

gpu/config/gpu_info_collector_linux.cc

 // Copyright 2014 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 "gpu/config/gpu_info_collector_linux.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_tokenizer.h"
 #include "base/strings/string_util.h"
 #include "base/trace_event/trace_event.h"
 #include "gpu/config/gpu_info_collector.h"
+#include "third_party/re2/src/re2/re2.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_implementation.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_switches.h"
 
 #if defined(USE_LIBPCI)
 #include "library_loaders/libpci.h"  // nogncheck
 #endif
 
@@ skipping 208 matching lines @@
   }
 
   gpu_info->basic_info_state = result;
   return result;
 }
 
 CollectInfoResult CollectDriverInfoGL(GPUInfo* gpu_info) {
   DCHECK(gpu_info);
 
   std::string gl_version = gpu_info->gl_version;
-  if (base::StartsWith(gl_version, "OpenGL ES", base::CompareCase::SENSITIVE))
-    gl_version = gl_version.substr(10);
   std::vector<std::string> pieces = base::SplitString(
       gl_version, base::kWhitespaceASCII, base::KEEP_WHITESPACE,
       base::SPLIT_WANT_NONEMPTY);
   // In linux, the gl version string might be in the format of
   //   GLVersion DriverVendor DriverVersion
   if (pieces.size() < 3)
     return kCollectInfoNonFatalFailure;
 
-  std::string driver_version = pieces[2];
-  size_t pos = driver_version.find_first_not_of("0123456789.");
-  if (pos == 0)
+  // Search from the end for the first piece that starts with major.minor or
+  // major.minor.micro but assume the driver version cannot be in the first two
+  // pieces.
+  std::string driver_version;
+  auto it = pieces.rbegin();
+  while (pieces.rend() - it > 2) {
+    bool parsed = re2::RE2::FullMatch(*it, "([\\d]+\\.[\\d]+(\\.[\\d]+)?).*",

[Ken Russell (switch to Gerrit), 2016/07/25 16:08:14]

Can you please see if there is a way using the re2 APIs to precompile this
regexp outside the inner loop?

[Julien Isorce Samsung, 2016/07/26 12:44:08]

Thx for the suggestion. Indeed there is api to do that. Done in Patch Set 9.

+                                      &driver_version);
+    if (parsed)
+      break;
+    ++it;
+  }
+
+  if (driver_version.empty())
     return kCollectInfoNonFatalFailure;
-  if (pos != std::string::npos)
-    driver_version = driver_version.substr(0, pos);
 
-  gpu_info->driver_vendor = pieces[1];
+  gpu_info->driver_vendor = *(++it);
   gpu_info->driver_version = driver_version;
   return kCollectInfoSuccess;
 }
 
 void MergeGPUInfo(GPUInfo* basic_gpu_info,
                   const GPUInfo& context_gpu_info) {
   MergeGPUInfoGL(basic_gpu_info, context_gpu_info);
 }
 
 }  // namespace gpu