Add support for displaying distilled articles.

components/dom_distiller/content/dom_distiller_viewer_source.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 "components/dom_distiller/content/dom_distiller_viewer_source.h"
 
 #include <string>
+#include <vector>
 
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/strings/string_util.h"
+#include "components/dom_distiller/core/dom_distiller_service.h"
+#include "components/dom_distiller/core/proto/distilled_page.pb.h"
+#include "components/dom_distiller/core/task_tracker.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_view_host.h"
+#include "grit/component_strings.h"
+#include "grit/dom_distiller_resources.h"
+#include "net/base/escape.h"
 #include "net/url_request/url_request.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/resource/resource_bundle.h"
 #include "url/gurl.h"
 
+namespace {
+
+std::string ReplaceHtmlTemplateValues(std::string title, std::string content) {
+  base::StringPiece html_template =
+      ResourceBundle::GetSharedInstance().GetRawDataResource(
+          IDR_DOM_DISTILLER_VIEWER_HTML);
+  std::vector<std::string> substitutions;
+  substitutions.push_back(title);    // $1
+  substitutions.push_back(title);    // $2
+  substitutions.push_back(content);  // $3
+  return ReplaceStringPlaceholders(html_template, substitutions, NULL);
+}
+
+}  // namespace
+
 namespace dom_distiller {
 
-DomDistillerViewerSource::DomDistillerViewerSource(const std::string& scheme)
-    : scheme_(scheme) {}
+// Handles receiving data asynchronously for a specific entry, and passing
+// it along to the data callback for the data source.
+class RequestViewerHandle : public ViewRequestDelegate {
+ public:
+  explicit RequestViewerHandle(
+      const content::URLDataSource::GotDataCallback& callback);
+  virtual ~RequestViewerHandle();
+
+  // ViewRequestDelegate implementation.
+  virtual void OnArticleReady(DistilledPageProto* proto) OVERRIDE;
+
+  void TakeViewerHandle(scoped_ptr<ViewerHandle> viewer_handle);
+
+ private:
+  // The handle to the view request towards the DomDistillerService. It
+  // needs to be kept around to ensure the distillation request finishes.
+  scoped_ptr<ViewerHandle> viewer_handle_;
+
+  // This holds the callback to where the data retrieved is sent back.
+  content::URLDataSource::GotDataCallback callback_;
+};
+
+RequestViewerHandle::RequestViewerHandle(
+    const content::URLDataSource::GotDataCallback& callback)
+    : callback_(callback) {}
+
+RequestViewerHandle::~RequestViewerHandle() {}
+
+void RequestViewerHandle::OnArticleReady(DistilledPageProto* proto) {
+  DCHECK(proto);
+  std::string title;
+  std::string unsafe_article_html;
+  if (proto->has_title() && proto->has_html()) {
+    title = net::EscapeForHTML(proto->title());
+    unsafe_article_html = proto->html();
+  } else {
+    title = l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_TITLE);
+    unsafe_article_html =
+        l10n_util::GetStringUTF8(IDS_DOM_DISTILLER_VIEWER_NO_DATA_CONTENT);
+  }
+  std::string unsafe_page_html =
+      ReplaceHtmlTemplateValues(title, unsafe_article_html);
+  callback_.Run(base::RefCountedString::TakeString(&unsafe_page_html));
+  base::MessageLoop::current()->DeleteSoon(FROM_HERE, this);
+}
+
+void RequestViewerHandle::TakeViewerHandle(
+    scoped_ptr<ViewerHandle> viewer_handle) {
+  viewer_handle_ = viewer_handle.Pass();
+}
+
+DomDistillerViewerSource::DomDistillerViewerSource(
+    DomDistillerService* dom_distiller_service,
+    const std::string& scheme)
+    : scheme_(scheme), dom_distiller_service_(dom_distiller_service) {}
 
 DomDistillerViewerSource::~DomDistillerViewerSource() {}
 
 std::string DomDistillerViewerSource::GetSource() const { return scheme_; }
 
 void DomDistillerViewerSource::StartDataRequest(
     const std::string& path,
     int render_process_id,
     int render_frame_id,
     const content::URLDataSource::GotDataCallback& callback) {
   content::RenderFrameHost* render_frame_host =
       content::RenderFrameHost::FromID(render_process_id, render_frame_id);
   DCHECK(render_frame_host);
   content::RenderViewHost* render_view_host =
       render_frame_host->GetRenderViewHost();
   DCHECK(render_view_host);
   CHECK_EQ(0, render_view_host->GetEnabledBindings());
 
-  std::string page_template = "Aloha!";
-  callback.Run(base::RefCountedString::TakeString(&page_template));
+  RequestViewerHandle* request_viewer_handle =
+      new RequestViewerHandle(callback);
+  std::string entry_id = StringToUpperASCII(path);
+  scoped_ptr<ViewerHandle> viewer_handle =
+      dom_distiller_service_->ViewEntry(request_viewer_handle, entry_id);
+  if (viewer_handle) {
+    // The service returned a |ViewerHandle| and guarantees it will call
+    // the |RequestViewerHandle|, so passing ownership to it, to ensure the
+    // request is not cancelled. The |RequestViewerHandle| will delete itself
+    // after receiving the callback.
+    request_viewer_handle->TakeViewerHandle(viewer_handle.Pass());
+  } else {
+    // The service did not return a |ViewerHandle|, which means the
+    // |RequestViewerHandle| will never be called, so clean up now.
+    delete request_viewer_handle;
+
+    std::string title = l10n_util::GetStringUTF8(
+        IDS_DOM_DISTILLER_VIEWER_FAILED_TO_FIND_ARTICLE_TITLE);
+    std::string content = l10n_util::GetStringUTF8(
+        IDS_DOM_DISTILLER_VIEWER_FAILED_TO_FIND_ARTICLE_CONTENT);
+    std::string html = ReplaceHtmlTemplateValues(title, content);
+    callback.Run(base::RefCountedString::TakeString(&html));
+  }
 };
 
 std::string DomDistillerViewerSource::GetMimeType(const std::string& path)
     const {
-  return "text/plain";
+  return "text/html";
 }
 
 bool DomDistillerViewerSource::ShouldServiceRequest(
     const net::URLRequest* request) const {
   return request->url().SchemeIs(scheme_.c_str());
 }
 
+void DomDistillerViewerSource::WillServiceRequest(
+    const net::URLRequest* request,
+    std::string* path) const {
+  // Since the full request is not available to StartDataRequest, replace the
+  // path to contain the data needed.
+  *path = request->url().host();
+};
+
 }  // namespace dom_distiller