Implementing URL prefix match for history thumbnail cache.

chrome/browser/ui/webui/ntp/thumbnail_source.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 "chrome/browser/ui/webui/ntp/thumbnail_source.h"
 
 #include "base/callback.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/instant_io_context.h"
 #include "chrome/browser/thumbnails/thumbnail_service.h"
 #include "chrome/browser/thumbnails/thumbnail_service_factory.h"
 #include "chrome/common/url_constants.h"
 #include "grit/theme_resources.h"
 #include "net/url_request/url_request.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "url/gurl.h"
 
 using content::BrowserThread;
 
-// Set ThumbnailService now as Profile isn't thread safe.
+// Set ThumbnailService now as Profile isn't thread safe. By default, perform
+// exact match only.
 ThumbnailSource::ThumbnailSource(Profile* profile)
     : thumbnail_service_(ThumbnailServiceFactory::GetForProfile(profile)),
-      profile_(profile) {
+      profile_(profile),
+      prefix_match_(false) {
+}
+
+ThumbnailSource::ThumbnailSource(Profile* profile, bool prefix_match)
+    : thumbnail_service_(ThumbnailServiceFactory::GetForProfile(profile)),
+      profile_(profile),
+      prefix_match_(prefix_match) {
 }
 
 ThumbnailSource::~ThumbnailSource() {
 }
 
 std::string ThumbnailSource::GetSource() const {
-  return chrome::kChromeUIThumbnailHost;
+  return prefix_match_ ?
+      chrome::kChromeUIThumbnailHost2 : chrome::kChromeUIThumbnailHost;
 }
 
 void ThumbnailSource::StartDataRequest(
     const std::string& path,
     int render_process_id,
     int render_view_id,
     const content::URLDataSource::GotDataCallback& callback) {
   scoped_refptr<base::RefCountedMemory> data;
-  if (thumbnail_service_->GetPageThumbnail(GURL(path), &data)) {
+  if (thumbnail_service_->GetPageThumbnail(GURL(path), prefix_match_, &data)) {
     // We have the thumbnail.
     callback.Run(data.get());
   } else {
     callback.Run(default_thumbnail_.get());
   }
 }
 
 std::string ThumbnailSource::GetMimeType(const std::string&) const {
   // We need to explicitly return a mime type, otherwise if the user tries to
   // drag the image they get no extension.
   return "image/png";
 }
 
 base::MessageLoop* ThumbnailSource::MessageLoopForRequestPath(
     const std::string& path) const {
   // TopSites can be accessed from the IO thread.
   return thumbnail_service_.get() ?
       NULL : content::URLDataSource::MessageLoopForRequestPath(path);
 }
 
 bool ThumbnailSource::ShouldServiceRequest(
     const net::URLRequest* request) const {
   if (request->url().SchemeIs(chrome::kChromeSearchScheme))
     return InstantIOContext::ShouldServiceRequest(request);
   return URLDataSource::ShouldServiceRequest(request);
 }