Cache --whitelisted-extension-id in SimpleFeature.

extensions/common/features/simple_feature.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 "extensions/common/features/simple_feature.h"
 
 #include <algorithm>
 #include <map>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/alias.h"
+#include "base/macros.h"
 #include "base/sha1.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "extensions/common/extension_api.h"
 #include "extensions/common/features/feature_provider.h"
 #include "extensions/common/switches.h"
 
 namespace extensions {
@@ skipping 191 matching lines @@
 
 bool IsCommandLineSwitchEnabled(const std::string& switch_name) {
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
   if (command_line->HasSwitch(switch_name + "=1"))
     return true;
   if (command_line->HasSwitch(std::string("enable-") + switch_name))
     return true;
   return false;
 }
 
+bool IsWhitelistedByCommandLine(const std::string& extension_id) {
+  // A singleton copy of the --whitelisted-extension-id so that we don't need to
+  // copy it from the CommandLine each time.
+  CR_DEFINE_STATIC_LOCAL(
+      std::string, whitelisted_extension_id,
+      (base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(

[not at google - send to devlin, 2015/03/31 17:16:05]

why are the parens around the base::CommandLine... call necessary? looks a bit
odd.

[jackhou1, 2015/03/31 21:53:41]

The macro is just:
#define CR_DEFINE_STATIC_LOCAL(type, name, arguments) \
  static type& name = *new type arguments

so the () in |arguments| becomes part of the constructor syntax.

[not at google - send to devlin, 2015/03/31 22:10:04]

Well, that's silly. Macros are supposed to put parens around expressions
themselves. The CR_DEFINE_STATIC_LOCAL macro should be fixed.

[jackhou1, 2015/03/31 22:19:18]

Yeah probably, looks like it was originally copied from WebKit, so I can't tell
if there was a good reason for it.

+          switches::kWhitelistedExtensionID)));
+  return !whitelisted_extension_id.empty() &&
+         whitelisted_extension_id == extension_id;
+}
+
 }  // namespace
 
 struct SimpleFeature::Mappings {
   Mappings() {
     extension_types["extension"] = Manifest::TYPE_EXTENSION;
     extension_types["theme"] = Manifest::TYPE_THEME;
     extension_types["legacy_packaged_app"] = Manifest::TYPE_LEGACY_PACKAGED_APP;
     extension_types["hosted_app"] = Manifest::TYPE_HOSTED_APP;
     extension_types["platform_app"] = Manifest::TYPE_PLATFORM_APP;
     extension_types["shared_module"] = Manifest::TYPE_SHARED_MODULE;
@@ skipping 121 matching lines @@
   if (IsIdInBlacklist(extension_id))
     return CreateAvailability(FOUND_IN_BLACKLIST, type);
 
   // TODO(benwells): don't grant all component extensions.
   // See http://crbug.com/370375 for more details.
   // Component extensions can access any feature.
   // NOTE: Deliberately does not match EXTERNAL_COMPONENT.
   if (component_extensions_auto_granted_ && location == Manifest::COMPONENT)
     return CreateAvailability(IS_AVAILABLE, type);
 
-  if (!whitelist_.empty()) {
-    if (!IsIdInWhitelist(extension_id)) {
-      // TODO(aa): This is gross. There should be a better way to test the
-      // whitelist.
-      base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
-      if (!command_line->HasSwitch(switches::kWhitelistedExtensionID))
-        return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
-
-      std::string whitelist_switch_value =
-          base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-              switches::kWhitelistedExtensionID);
-      if (extension_id != whitelist_switch_value)
-        return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
-    }
+  if (!whitelist_.empty() && !IsIdInWhitelist(extension_id) &&
+      !IsWhitelistedByCommandLine(extension_id)) {
+    return CreateAvailability(NOT_FOUND_IN_WHITELIST, type);
   }
 
   if (!MatchesManifestLocation(location))
     return CreateAvailability(INVALID_LOCATION, type);
 
   if (!platforms_.empty() && !ContainsValue(platforms_, platform))
     return CreateAvailability(INVALID_PLATFORM, type);
 
   if (min_manifest_version_ != 0 && manifest_version < min_manifest_version_)
     return CreateAvailability(INVALID_MIN_MANIFEST_VERSION, type);
@@ skipping 226 matching lines @@
 bool SimpleFeature::IsValidExtensionId(const std::string& extension_id) {
   // Belt-and-suspenders philosophy here. We should be pretty confident by this
   // point that we've validated the extension ID format, but in case something
   // slips through, we avoid a class of attack where creative ID manipulation
   // leads to hash collisions.
   // 128 bits / 4 = 32 mpdecimal characters
   return (extension_id.length() == 32);
 }
 
 }  // namespace extensions