[Downloads] Expose basic download history to UI

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/location.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/grit/generated_resources.h"
 #include "content/public/browser/browser_context.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;
 
+using DownloadVector = content::DownloadManager::DownloadVector;
+
 // static
 bool DownloadManagerService::RegisterDownloadManagerService(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 static jlong Init(JNIEnv* env, const JavaParamRef<jobject>& jobj) {
   Profile* profile = ProfileManager::GetActiveUserProfile();
   DownloadManagerService* service =
       new DownloadManagerService(env, jobj);
   DownloadService* download_service =
@@ skipping 30 matching lines @@
     JNIEnv* env,
     jobject obj,
     const JavaParamRef<jstring>& jdownload_guid) {
   std::string download_guid = ConvertJavaStringToUTF8(env, jdownload_guid);
   if (is_history_query_complete_)
     PauseDownloadInternal(download_guid);
   else
     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;
+
+  DownloadVector all_items;
+  manager->GetAllDownloads(&all_items);
+
+  // Create a list in Java-land and then add information about all the
+  // downloads to it.
+  JNIEnv* env = base::android::AttachCurrentThread();

[qinmin, 2016/07/14 17:08:05]

Since we always call onAllDownloadsRetrieved, can we just skipping creating the
empty list and pass an array of objects from native to java, and create the list
in java at that time?

[gone, 2016/07/14 17:11:08]

This is actually what the DownloadsBridge does, so we're just mimicking what's
going on there.

But how would you actually pass the objects?  Would we create 4 jstring arrays
and 2 jlong arrays?  Is that a thing we can do?

[qinmin, 2016/07/14 18:06:54]

You can call a jni call to pack the fields into a jobject and return it, so at
the end, just an array of jobjects

[Ian Wen, 2016/07/14 18:16:26]

Aha! I found a trick that BookmarkBridge did to simplify the code by a tiny
margin: in GetAllDownloas(), java side passes a java list directly to native and
let it cache it for returning.

This is a nit though. orz

[gone, 2016/07/14 19:11:56]

Changed it around to create the jobjectarray like Min suggested; lmk if this
looks right.

+  ScopedJavaLocalRef<jobject> jdownload_item_list =
+      Java_DownloadManagerService_createDownloadItemList(
+          env, java_ref_.obj());
+
+  for (size_t i = 0; i < all_items.size(); i++) {
+    content::DownloadItem* item = all_items[i];
+    if (item->IsTemporary() ||
+        item->GetFileNameToReportUser().empty() ||
+        item->GetTargetFilePath().empty()) {
+      continue;
+    }
+
+    Java_DownloadManagerService_addItemToDownloadItemList(
+        env,
+        java_ref_.obj(),
+        jdownload_item_list.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());
+  }
+
+  Java_DownloadManagerService_onAllDownloadsRetrieved(
+      env, java_ref_.obj(), jdownload_item_list.obj());
+}
+
+
 void DownloadManagerService::CancelDownload(
     JNIEnv* env,
     jobject obj,
     const JavaParamRef<jstring>& jdownload_guid,
     bool is_off_the_record,
     bool is_notification_dismissed) {
   std::string download_guid = ConvertJavaStringToUTF8(env, jdownload_guid);
 
   DownloadController::RecordDownloadCancelReason(
       is_notification_dismissed ?
@@ skipping 21 matching lines @@
     switch (action) {
       case RESUME:
         ResumeDownloadInternal(download_guid);
         break;
       case PAUSE:
         PauseDownloadInternal(download_guid);
         break;
       case CANCEL:
         CancelDownloadInternal(download_guid, false);
         break;
+      case INITIALIZE_UI:
+        GetAllDownloadsInternal();
+        break;
       default:
         NOTREACHED();
         break;
     }
   }
   pending_actions_.clear();
 }
 
 void DownloadManagerService::ResumeDownloadInternal(
     const std::string& download_guid) {
@@ skipping 54 matching lines @@
       if (iter->second == PAUSE)
         iter->second = action;
       break;
     case PAUSE:
       if (iter->second == RESUME)
         iter->second = action;
       break;
     case CANCEL:
       iter->second = action;
       break;
+    case INITIALIZE_UI:
+      iter->second = action;
+      break;
     default:
       NOTREACHED();
       break;
   }
 }
 
 void DownloadManagerService::OnResumptionFailed(
     const std::string& download_guid) {
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(&DownloadManagerService::OnResumptionFailedInternal,
@@ skipping 14 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);
 }