Web Share for Chrome OS: Delete shared files after delay

To avoid the accumulation of shared files on Chromebooks that
are restarted infrequently, we delete shared files 10 minutes
after the share dialog completes.


Design doc:
https://docs.google.com/document/d/1EjpgseTbBhT9ogQv6HV6sLlBl4hpb2viOcmPtFJorMQ/


Bug: 1153215
Change-Id: Iff221b79b7e6d9e92e47081bdea4ebbf30f37776
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2581704
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Auto-Submit: Eric Willigers <ericwilligers@chromium.org>
Reviewed-by: Alexey Baskakov <loyso@chromium.org>
Cr-Commit-Position: refs/heads/master@{#835964}

chrome/browser/webshare/chromeos/BUILD.gn

@@ -34,6 +34,7 @@ source_set("unit_tests") {
     "//base/test:test_support",
     "//build:chromeos_buildflags",
     "//chrome/browser",
+    "//chrome/browser/chromeos:chromeos",
     "//chrome/common",
     "//chrome/test:test_support",
     "//content/public/browser",

chrome/browser/webshare/chromeos/prepare_directory_task.cc

@@ -6,7 +6,6 @@
 
 #include "base/files/file.h"
 #include "base/files/file_enumerator.h"
-#include "base/files/file_util.h"
 #include "base/system/sys_info.h"
 #include "base/task/task_traits.h"
 #include "base/task/thread_pool.h"
@@ -16,6 +15,18 @@
 
 using content::BrowserThread;
 
+namespace {
+
+void DeleteSharedFiles(std::vector<base::FilePath> file_paths) {
+  base::ScopedBlockingCall scoped_blocking_call(FROM_HERE,
+                                                base::BlockingType::WILL_BLOCK);
+  for (const base::FilePath& name : file_paths) {
+    base::DeleteFile(name);
+  }
+}
+
+}  // namespace
+
 namespace webshare {
 
 constexpr base::TimeDelta PrepareDirectoryTask::kSharedFileLifetime;
@@ -40,6 +51,15 @@ void PrepareDirectoryTask::Start() {
                      weak_ptr_factory_.GetWeakPtr()));
 }
 
+// static
+void PrepareDirectoryTask::ScheduleSharedFileDeletion(
+    std::vector<base::FilePath> file_paths,
+    base::TimeDelta delay) {
+  base::ThreadPool::PostDelayedTask(
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::BEST_EFFORT},
+      base::BindOnce(&DeleteSharedFiles, std::move(file_paths)), delay);
+}
+
 // static
 base::File::Error PrepareDirectoryTask::PrepareDirectory(
     base::FilePath directory,

chrome/browser/webshare/chromeos/prepare_directory_task.h

@@ -27,6 +27,10 @@ class PrepareDirectoryTask {
   PrepareDirectoryTask& operator=(const PrepareDirectoryTask&) = delete;
   ~PrepareDirectoryTask();
 
+  // Deletes specified |file_paths| after waiting |delay|.
+  static void ScheduleSharedFileDeletion(std::vector<base::FilePath> file_paths,
+                                         base::TimeDelta delay);
+
   // Launches the task. |callback_| will be called on the original (UI) thread
   // when the task completes.
   void Start();

chrome/browser/webshare/chromeos/sharesheet_client.cc

@@ -157,6 +157,8 @@ void SharesheetClient::SetSharesheetCallbackForTesting(
 
 void SharesheetClient::OnPrepareDirectory(blink::mojom::ShareError error) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!current_share_.has_value())
+    return;
 
   if (!web_contents() || error != blink::mojom::ShareError::OK) {
     std::move(current_share_->callback).Run(error);
@@ -183,9 +185,13 @@ void SharesheetClient::OnPrepareDirectory(blink::mojom::ShareError error) {
 
 void SharesheetClient::OnStoreFiles(blink::mojom::ShareError error) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!current_share_.has_value())
+    return;
 
   if (!web_contents() || error != blink::mojom::ShareError::OK) {
     std::move(current_share_->callback).Run(error);
+    PrepareDirectoryTask::ScheduleSharedFileDeletion(
+        std::move(current_share_->file_paths), base::TimeDelta::FromMinutes(0));
     current_share_ = base::nullopt;
     return;
   }
@@ -198,7 +204,13 @@ void SharesheetClient::OnStoreFiles(blink::mojom::ShareError error) {
 }
 
 void SharesheetClient::OnShowSharesheet(sharesheet::SharesheetResult result) {
+  if (!current_share_.has_value())
+    return;
+
   std::move(current_share_->callback).Run(SharesheetResultToShareError(result));
+  PrepareDirectoryTask::ScheduleSharedFileDeletion(
+      std::move(current_share_->file_paths),
+      PrepareDirectoryTask::kSharedFileLifetime);
   current_share_ = base::nullopt;
 }
 

chrome/browser/webshare/chromeos/sharesheet_client_unittest.cc

@@ -9,12 +9,16 @@
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
+#include "base/files/file_util.h"
 #include "base/memory/scoped_refptr.h"
 #include "base/run_loop.h"
 #include "base/test/bind.h"
 #include "base/test/task_environment.h"
+#include "chrome/browser/chromeos/file_manager/path_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sharesheet/sharesheet_types.h"
+#include "chrome/browser/webshare/chromeos/prepare_directory_task.h"
+#include "chrome/browser/webshare/chromeos/store_file_task.h"
 #include "chrome/test/base/chrome_render_view_host_test_harness.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/test/web_contents_tester.h"
@@ -103,4 +107,47 @@ TEST_F(SharesheetClientUnitTest, TestWithoutFilesInIncognito) {
   EXPECT_EQ(error, blink::mojom::ShareError::OK);
 }
 
+TEST_F(SharesheetClientUnitTest, DeleteAfterShare) {
+  SharesheetClient sharesheet_client(web_contents());
+  const base::FilePath my_files =
+      file_manager::util::GetMyFilesFolderForProfile(profile());
+  const base::FilePath first_file =
+      my_files.AppendASCII(".WebShare/share1.txt");
+  const base::FilePath second_file =
+      my_files.AppendASCII(".WebShare/share2.txt");
+
+  const std::string title = "Subject";
+  const std::string text = "Message";
+  const GURL share_url("https://example.com/");
+  std::vector<blink::mojom::SharedFilePtr> files;
+  files.push_back(blink::mojom::SharedFile::New(
+      first_file.AsUTF8Unsafe(), blink::mojom::SerializedBlob::New()));
+  files.push_back(blink::mojom::SharedFile::New(
+      second_file.AsUTF8Unsafe(), blink::mojom::SerializedBlob::New()));
+
+  base::RunLoop run_loop;
+  blink::mojom::ShareError error = blink::mojom::ShareError::INTERNAL_ERROR;
+  StoreFileTask::SkipCopyingForTesting();
+  sharesheet_client.Share(
+      title, text, share_url, std::move(files),
+      base::BindLambdaForTesting(
+          [&run_loop, &error](blink::mojom::ShareError in_error) {
+            error = in_error;
+            run_loop.Quit();
+          }));
+
+  run_loop.Run();
+  EXPECT_EQ(error, blink::mojom::ShareError::OK);
+
+  task_environment()->FastForwardBy(PrepareDirectoryTask::kSharedFileLifetime /
+                                    2);
+  EXPECT_TRUE(base::PathExists(first_file));
+  EXPECT_TRUE(base::PathExists(second_file));
+
+  task_environment()->FastForwardBy(PrepareDirectoryTask::kSharedFileLifetime *
+                                    2);
+  EXPECT_FALSE(base::PathExists(first_file));
+  EXPECT_FALSE(base::PathExists(second_file));
+}
+
 }  // namespace webshare

chrome/browser/webshare/chromeos/store_file_task.cc

@@ -27,6 +27,17 @@ StoreFileTask::StoreFileTask(base::FilePath filename,
 StoreFileTask::~StoreFileTask() = default;
 
 void StoreFileTask::Start() {
+  {
+    base::ScopedBlockingCall scoped_blocking_call(
+        FROM_HERE, base::BlockingType::WILL_BLOCK);
+    output_file_.Initialize(
+        filename_, base::File::FLAG_CREATE_ALWAYS | base::File::FLAG_WRITE);
+  }
+
+  (this->*GetStartReadFunc())();
+}
+
+void StoreFileTask::StartRead() {
   constexpr size_t kDataPipeCapacity = 65536;
 
   MojoCreateDataPipeOptions options;
@@ -42,18 +53,16 @@ void StoreFileTask::Start() {
     return;
   }
 
-  {
-    base::ScopedBlockingCall scoped_blocking_call(
-        FROM_HERE, base::BlockingType::WILL_BLOCK);
-    output_file_.Initialize(
-        filename_, base::File::FLAG_CREATE_ALWAYS | base::File::FLAG_WRITE);
-  }
-
   mojo::Remote<blink::mojom::Blob> blob(std::move(file_->blob->blob));
   blob->ReadAll(std::move(producer_handle),
                 receiver_.BindNewPipeAndPassRemote());
 }
 
+// static
+void StoreFileTask::SkipCopyingForTesting() {
+  GetStartReadFunc() = &StoreFileTask::OnSuccess;
+}
+
 void StoreFileTask::OnDataPipeReadable(MojoResult result) {
   if (result != MOJO_RESULT_OK) {
     if (!received_all_data_) {
@@ -144,4 +153,11 @@ void StoreFileTask::OnComplete(int32_t status, uint64_t data_length) {
     OnSuccess();
 }
 
+// static
+StoreFileTask::StartReadFunc& StoreFileTask::GetStartReadFunc() {
+  static StartReadFunc start_read_func = &StoreFileTask::StartRead;
+
+  return start_read_func;
+}
+
 }  // namespace webshare

chrome/browser/webshare/chromeos/store_file_task.h

@@ -31,7 +31,13 @@ class StoreFileTask : public blink::mojom::BlobReaderClient {
   // Must be called on a thread that allows blocking IO.
   void Start();
 
+  // Create empty files instead of copying from the SharedFilePtr.
+  static void SkipCopyingForTesting();
+
  private:
+  using StartReadFunc = void (StoreFileTask::*)();
+
+  void StartRead();
   void OnDataPipeReadable(MojoResult result);
   void OnSuccess();
 
@@ -40,6 +46,8 @@ class StoreFileTask : public blink::mojom::BlobReaderClient {
                         uint64_t expected_content_size) override;
   void OnComplete(int32_t status, uint64_t data_length) override;
 
+  static StartReadFunc& GetStartReadFunc();
+
   base::FilePath filename_;
   blink::mojom::SharedFilePtr file_;
   uint64_t& available_space_;