Upstream iOS implementation of dom_distiller

components/dom_distiller/ios/distiller_page_ios.mm

+// 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/ios/distiller_page_ios.h"
+
+#import <UIKit/UIKit.h>
+
+#include "base/json/json_reader.h"
+#include "base/logging.h"
+#include "base/strings/sys_string_conversions.h"
+#include "base/values.h"
+#include "ios/public/provider/web/web_controller_provider.h"
+#include "ios/web/public/browser_state.h"
+
+namespace dom_distiller {
+
+// Helper class for observing the loading of URLs to distill.
+class DistillerWebStateObserver : public web::WebStateObserver {
+ public:
+  DistillerWebStateObserver(web::WebState* web_state,
+                            DistillerPageIOS* distiller_page);
+
+  // WebStateObserver implementation:
+  void PageLoaded(
+      web::PageLoadCompletionStatus load_completion_status) override;
+
+ private:
+  DistillerPageIOS* distiller_page_;  // weak, owns this object.
+};
+
+DistillerWebStateObserver::DistillerWebStateObserver(
+    web::WebState* web_state,
+    DistillerPageIOS* distiller_page)
+    : web::WebStateObserver(web_state), distiller_page_(distiller_page) {
+  DCHECK(web_state);
+  DCHECK(distiller_page_);
+}
+
+void DistillerWebStateObserver::PageLoaded(
+    web::PageLoadCompletionStatus load_completion_status) {
+  distiller_page_->OnLoadURLDone(load_completion_status);
+}
+
+#pragma mark -
+
+DistillerPageIOS::DistillerPageIOS(web::BrowserState* browser_state)
+    : browser_state_(browser_state), weak_ptr_factory_(this) {
+}
+
+DistillerPageIOS::~DistillerPageIOS() {
+}
+
+void DistillerPageIOS::DistillPageImpl(const GURL& url,
+                                       const std::string& script) {
+  if (!url.is_valid() || !script.length())
+    return;
+  url_ = url;
+  script_ = script;
+
+  // Lazily create provider.
+  if (!provider_) {
+    if (ios::GetWebControllerProviderFactory()) {
+      provider_ =
+          ios::GetWebControllerProviderFactory()->CreateWebControllerProvider(
+              browser_state_);
+      web_state_observer_.reset(
+          new DistillerWebStateObserver(provider_->GetWebState(), this));
+    }
+  }
+
+  // Load page using provider.
+  if (provider_)
+    provider_->LoadURL(url_);
+  else
+    OnLoadURLDone(web::PageLoadCompletionStatus::FAILURE);
+}
+
+void DistillerPageIOS::OnLoadURLDone(
+    web::PageLoadCompletionStatus load_completion_status) {
+  // Don't attempt to distill if the page load failed or if there is no
+  // provider.
+  if (load_completion_status == web::PageLoadCompletionStatus::FAILURE ||
+      !provider_) {
+    HandleJavaScriptResultString(@"");
+    return;
+  }
+
+  // Inject the script.
+  base::WeakPtr<DistillerPageIOS> weak_this = weak_ptr_factory_.GetWeakPtr();
+  provider_->InjectScript(script_, ^(NSString* string, NSError* error) {
+    DistillerPageIOS* distiller_page = weak_this.get();
+    if (distiller_page)
+      distiller_page->HandleJavaScriptResultString(string);
+  });
+}
+
+void DistillerPageIOS::HandleJavaScriptResultString(NSString* result) {
+  scoped_ptr<base::Value> resultValue(base::Value::CreateNullValue());
+  if (result.length) {
+    scoped_ptr<base::Value> dictionaryValue(
+        base::JSONReader::Read(base::SysNSStringToUTF8(result)));
+    if (dictionaryValue &&
+        dictionaryValue->IsType(base::Value::TYPE_DICTIONARY)) {
+      resultValue = dictionaryValue.Pass();
+    }
+  }
+  OnDistillationDone(url_, resultValue.get());
+}
+
+}  // namespace dom_distiller