Prevent duplicate concurrent installs of the same extension

chrome/browser/apps/ephemeral_app_launcher.cc

 // Copyright 2013 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/apps/ephemeral_app_launcher.h"
 
 #include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_install_checker.h"
 #include "chrome/browser/extensions/extension_install_prompt.h"
@@ skipping 206 matching lines @@
   if (!extensions::util::IsAppLaunchable(extension->id(), profile())) {
     *reason = webstore_install::REQUIREMENT_VIOLATIONS;
     *error = kRequirementsError;
     return false;
   }
 
   return true;
 }
 
 void EphemeralAppLauncher::EnableInstalledApp(const Extension* extension) {
+  // Check whether an install is already in progress.
+  webstore_install::Result result = webstore_install::UNKNOWN_ERROR;
+  std::string error;
+  if (!EnsureUniqueInstall(&result, &error)) {
+    InvokeCallback(result, error);
+    return;
+  }
+
+  // Keep this object alive until the enable flow is complete. Either
+  // ExtensionEnableFlowFinished() or ExtensionEnableFlowAborted() will be
+  // called.
+  AddRef();
+
   extension_enable_flow_.reset(
       new ExtensionEnableFlow(profile(), extension->id(), this));
   if (web_contents())
     extension_enable_flow_->StartForWebContents(web_contents());
   else
     extension_enable_flow_->StartForNativeWindow(parent_window_);
-
-  // Keep this object alive until the enable flow is complete. Either
-  // ExtensionEnableFlowFinished() or ExtensionEnableFlowAborted() will be
-  // called.
-  AddRef();
 }
 
 void EphemeralAppLauncher::MaybeLaunchApp() {
   webstore_install::Result result = webstore_install::UNKNOWN_ERROR;
   std::string error;
 
   ExtensionRegistry* registry = ExtensionRegistry::Get(profile());
   const Extension* extension =
       registry->GetExtensionById(id(), ExtensionRegistry::EVERYTHING);
   if (extension) {
@@ skipping 37 matching lines @@
   chrome::NavigateParams params(
       displayer.browser(), launch_url, content::PAGE_TRANSITION_AUTO_TOPLEVEL);
   params.disposition = NEW_FOREGROUND_TAB;
   chrome::Navigate(&params);
   return true;
 }
 
 void EphemeralAppLauncher::InvokeCallback(webstore_install::Result result,
                                           const std::string& error) {
   if (!launch_callback_.is_null()) {
-    launch_callback_.Run(result, error);
+    LaunchCallback callback = launch_callback_;
     launch_callback_.Reset();
+    callback.Run(result, error);
   }
 }
 
 void EphemeralAppLauncher::AbortLaunch(webstore_install::Result result,
                                        const std::string& error) {
   InvokeCallback(result, error);
   WebstoreStandaloneInstaller::CompleteInstall(result, error);
 }
 
 void EphemeralAppLauncher::CheckEphemeralInstallPermitted() {
@@ skipping 25 matching lines @@
   if (!install_checker_->requirement_errors().empty()) {
     AbortLaunch(webstore_install::REQUIREMENT_VIOLATIONS,
                 install_checker_->requirement_errors().front());
     return;
   }
 
   // Proceed with the normal install flow.
   ProceedWithInstallPrompt();
 }
 
+void EphemeralAppLauncher::InitInstallData(
+    extensions::ActiveInstallData* install_data) const {
+  install_data->is_ephemeral = true;
+}
+
 bool EphemeralAppLauncher::CheckRequestorAlive() const {
   return dummy_web_contents_.get() != NULL || web_contents() != NULL;
 }
 
 const GURL& EphemeralAppLauncher::GetRequestorURL() const {
   return GURL::EmptyGURL();
 }
 
 bool EphemeralAppLauncher::ShouldShowPostInstallUI() const {
   return false;
@@ skipping 80 matching lines @@
   WebstoreStandaloneInstaller::CompleteInstall(result, error);
 }
 
 void EphemeralAppLauncher::WebContentsDestroyed() {
   launch_callback_.Reset();
   AbortInstall();
 }
 
 void EphemeralAppLauncher::ExtensionEnableFlowFinished() {
   MaybeLaunchApp();
-  Release();  // Matches the AddRef in EnableInstalledApp().
+
+  // CompleteInstall will call Release.
+  WebstoreStandaloneInstaller::CompleteInstall(webstore_install::SUCCESS,
+                                               std::string());
 }
 
 void EphemeralAppLauncher::ExtensionEnableFlowAborted(bool user_initiated) {
-  InvokeCallback(webstore_install::USER_CANCELLED, kUserCancelledError);
-  Release();  // Matches the AddRef in EnableInstalledApp().
+  // CompleteInstall will call Release.
+  CompleteInstall(webstore_install::USER_CANCELLED, kUserCancelledError);
 }