Show download error message if sdcard is not available

chrome/browser/android/download/download_manager_service.cc

 // Copyright 2015 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/android/download/download_manager_service.h"
 
 #include "base/android/jni_string.h"
+#include "base/files/file_util.h"
 #include "base/location.h"
+#include "base/path_service.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "chrome/browser/android/download/download_controller.h"
 #include "chrome/browser/download/download_service.h"
 #include "chrome/browser/download/download_service_factory.h"
 #include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/common/chrome_paths.h"
 #include "chrome/grit/generated_resources.h"
 #include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_item.h"
 #include "jni/DownloadManagerService_jni.h"
 #include "ui/base/l10n/l10n_util.h"
 
 using base::android::JavaParamRef;
 using base::android::ConvertJavaStringToUTF8;
 using base::android::ConvertUTF8ToJavaString;
 
+namespace {
+// When sdcard is not available, check whether previously downloaded files under
+// document dir has been cleaned.
+bool are_downloads_under_document_dir_cleaned = false;
+}
+
+void ClearUnusedDownloads() {

[asanka, 2016/07/12 17:07:10]

This one is a bit tricky. Are there other components that may have written to
this directory? Any files written here would not be visible externally without
extra work. But it's not quite a given that a) DIR_USER_DOCUMENTS consists
solely of downloaded files, and b) all such files can be safely removed.

I'll defer to Android folks about the safety of what's been done here.

[qinmin, 2016/07/12 18:13:04]

Seems only download is using Documents dir, I added a TODO to remove this
function in the next chrome release.
Will ping tedchoc/yfriedman to confirm this is ok.

+  base::FilePath document_dir;
+  base::PathService::Get(chrome::DIR_USER_DOCUMENTS, &document_dir);
+  base::DeleteFile(document_dir, true);
+}
+
 // static
 bool DownloadManagerService::RegisterDownloadManagerService(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
+// static
+void DownloadManagerService::OnDownloadCanceled(
+    content::DownloadItem* download,
+    DownloadController::DownloadCancelReason reason) {
+  bool has_no_external_storage =
+      (reason == DownloadController::CANCEL_REASON_NO_EXTERNAL_STORAGE);
+  JNIEnv* env = base::android::AttachCurrentThread();
+  ScopedJavaLocalRef<jstring> jname =
+      ConvertUTF8ToJavaString(env, download->GetURL().ExtractFileName());
+  Java_DownloadManagerService_onDownloadItemCanceled(
+      env, jname.obj(), has_no_external_storage);
+  DownloadController::RecordDownloadCancelReason(reason);
+  if (has_no_external_storage && !are_downloads_under_document_dir_cleaned) {
+    content::BrowserThread::PostTask(
+        content::BrowserThread::FILE, FROM_HERE,
+        base::Bind(&ClearUnusedDownloads));
+    are_downloads_under_document_dir_cleaned = true;
+  }
+}
+
+
 static jlong Init(JNIEnv* env, const JavaParamRef<jobject>& jobj) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
   DownloadManagerService* service =
       new DownloadManagerService(env, jobj);
   DownloadService* download_service =
       DownloadServiceFactory::GetForBrowserContext(profile);
   DownloadHistory* history = download_service->GetDownloadHistory();
   if (history)
     history->AddObserver(service);
   return reinterpret_cast<intptr_t>(service);
@@ skipping 174 matching lines @@
     resume_callback_for_testing_.Run(false);
 }
 
 content::DownloadManager* DownloadManagerService::GetDownloadManager(
     bool is_off_the_record) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
   if (is_off_the_record)
     profile = profile->GetOffTheRecordProfile();
   return content::BrowserContext::GetDownloadManager(profile);
 }