[Downloads] Expose basic download history to UI

chrome/browser/android/download/download_manager_service.cc

Index: chrome/browser/android/download/download_manager_service.cc
diff --git a/chrome/browser/android/download/download_manager_service.cc b/chrome/browser/android/download/download_manager_service.cc
index 3c410a414ef7fe62c03ad89b921406593510e8ad..bf3129576ae73a7255b2216fac315887ea7ecb15 100644
--- a/chrome/browser/android/download/download_manager_service.cc
+++ b/chrome/browser/android/download/download_manager_service.cc
@@ -23,6 +23,16 @@ using base::android::JavaParamRef;
 using base::android::ConvertJavaStringToUTF8;
 using base::android::ConvertUTF8ToJavaString;
 
+namespace {
+
+bool ShouldShowDownloadItem(content::DownloadItem* item) {
+  return !item->IsTemporary() &&
+      !item->GetFileNameToReportUser().empty() &&
+      !item->GetTargetFilePath().empty();
+}
+
+}  // namespace
+
 // static
 bool DownloadManagerService::RegisterDownloadManagerService(JNIEnv* env) {
   return RegisterNativesImpl(env);
@@ -73,6 +83,63 @@ void DownloadManagerService::PauseDownload(
     EnqueueDownloadAction(download_guid, PAUSE);
 }
 
+void DownloadManagerService::GetAllDownloads(JNIEnv* env,
+                                             const JavaParamRef<jobject>& obj) {
+  if (is_history_query_complete_)
+    GetAllDownloadsInternal();
+  else
+    EnqueueDownloadAction(std::string(), INITIALIZE_UI);
+}
+
+void DownloadManagerService::GetAllDownloadsInternal() {
+  content::DownloadManager* manager = GetDownloadManager(false);
+  if (java_ref_.is_null() || !manager)
+    return;
+
+  content::DownloadManager::DownloadVector all_items;
+  manager->GetAllDownloads(&all_items);
+
+  // Determine how many items will be displayed.
+  int num_to_display = 0;
+  for (size_t i = 0; i < all_items.size(); i++) {
+    content::DownloadItem* item = all_items[i];
+    num_to_display += (ShouldShowDownloadItem(item) ? 1 : 0);
+  }
+
+  // Create a Java array of all of the visible DownloadItems.
+  JNIEnv* env = base::android::AttachCurrentThread();
+  ScopedJavaLocalRef<jclass> j_download_item_class = base::android::GetClass(

[qinmin, 2016/07/14 19:48:18]

This looks a little worse than the previous patch, i forgot to take jni array
creation into consideration. 
Sorry for all the inconvenience, revert this to the old patch would be better.

[gone, 2016/07/14 20:22:58]

No worries; I reverted most of it, but kept the function for
ShouldShowDownloadItem.  It might be helpful later.

+      env, "org/chromium/chrome/browser/download/DownloadItem");
+  ScopedJavaLocalRef<jobjectArray> j_item_array(
+      env,
+      env->NewObjectArray(
+          num_to_display, j_download_item_class.obj(), nullptr));
+
+  for (size_t i = 0, index = 0; i < all_items.size(); i++) {
+    content::DownloadItem* item = all_items[i];
+    if (!ShouldShowDownloadItem(item))
+      continue;
+
+    ScopedJavaLocalRef<jobject> j_item =
+        Java_DownloadManagerService_createDownloadItem(
+            env,
+            java_ref_.obj(),
+            ConvertUTF8ToJavaString(env, item->GetGuid()).obj(),
+            ConvertUTF8ToJavaString(
+                env,
+                item->GetFileNameToReportUser().BaseName().value()).obj(),
+            ConvertUTF8ToJavaString(env, item->GetTabUrl().spec()).obj(),
+            ConvertUTF8ToJavaString(env, item->GetMimeType()).obj(),
+            item->GetStartTime().ToJavaTime(),
+            item->GetTotalBytes());
+    env->SetObjectArrayElement(j_item_array.obj(), index++, j_item.obj());
+  }
+
+  Java_DownloadManagerService_onAllDownloadsRetrieved(
+      env, java_ref_.obj(), j_item_array.obj());
+}
+
+
 void DownloadManagerService::CancelDownload(
     JNIEnv* env,
     jobject obj,
@@ -114,6 +181,9 @@ void DownloadManagerService::OnHistoryQueryComplete() {
       case CANCEL:
         CancelDownloadInternal(download_guid, false);
         break;
+      case INITIALIZE_UI:
+        GetAllDownloadsInternal();

[qinmin, 2016/07/14 19:48:18]

Do you need to check whether user has closed the download home activity at this
moment?

[gone, 2016/07/14 20:22:58]

Should be fine: the Adapter is owned by the DownloadManagerService, so checking
if that java_ref is valid is OK.

+        break;
       default:
         NOTREACHED();
         break;
@@ -188,6 +258,9 @@ void DownloadManagerService::EnqueueDownloadAction(
     case CANCEL:
       iter->second = action;
       break;
+    case INITIALIZE_UI:
+      iter->second = action;
+      break;
     default:
       NOTREACHED();
       break;