mediaview: Support watchers in ArcDocumentsProviderRoot.

chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc

Index: chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc
diff --git a/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc b/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc
index 8264bcad61dcee21f2018dcbc5eb01a53d092985..cbfd83fa2aca0443c0309fed3443db85be25bcba 100644
--- a/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc
+++ b/chrome/browser/chromeos/arc/fileapi/arc_documents_provider_root.cc
@@ -95,6 +95,36 @@ void ArcDocumentsProviderRoot::ReadDirectory(
                        weak_ptr_factory_.GetWeakPtr(), callback));
 }
 
+void ArcDocumentsProviderRoot::AddWatcher(
+    const base::FilePath& path,
+    const WatcherCallback& watcher_callback,
+    const StatusCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (path_to_watcher_id_.count(path)) {
+    callback.Run(base::File::FILE_ERROR_FAILED);
+    return;
+  }
+  ResolveToDocumentId(
+      path, base::Bind(&ArcDocumentsProviderRoot::AddWatcherWithDocumentId,
+                       weak_ptr_factory_.GetWeakPtr(), path, watcher_callback,
+                       callback));
+}
+
+void ArcDocumentsProviderRoot::RemoveWatcher(const base::FilePath& path,
+                                             const StatusCallback& callback) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  auto iter = path_to_watcher_id_.find(path);
+  if (iter == path_to_watcher_id_.end()) {
+    callback.Run(base::File::FILE_ERROR_FAILED);
+    return;
+  }
+  int64_t watcher_id = iter->second;
+  path_to_watcher_id_.erase(iter);
+  file_system_operation_runner_util::RemoveWatcherOnIOThread(
+      watcher_id, base::Bind(&ArcDocumentsProviderRoot::RemoveWatcherDone,
+                             weak_ptr_factory_.GetWeakPtr(), callback));
+}
+
 void ArcDocumentsProviderRoot::ResolveToContentUrl(
     const base::FilePath& path,
     const ResolveToContentUrlCallback& callback) {
@@ -182,6 +212,54 @@ void ArcDocumentsProviderRoot::ReadDirectoryWithNameToThinDocumentMap(
   callback.Run(base::File::FILE_OK, entry_list, false /* has_more */);
 }
 
+void ArcDocumentsProviderRoot::AddWatcherWithDocumentId(
+    const base::FilePath& path,
+    const WatcherCallback& watcher_callback,
+    const StatusCallback& callback,
+    const std::string& document_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (document_id.empty()) {
+    callback.Run(base::File::FILE_ERROR_NOT_FOUND);
+    return;
+  }
+  file_system_operation_runner_util::AddWatcherOnIOThread(
+      authority_, document_id, watcher_callback,
+      base::Bind(&ArcDocumentsProviderRoot::AddWatcherDone,
+                 weak_ptr_factory_.GetWeakPtr(), path, callback));
+}
+
+void ArcDocumentsProviderRoot::AddWatcherDone(const base::FilePath& path,
+                                              const StatusCallback& callback,
+                                              int64_t watcher_id) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (watcher_id < 0) {
+    callback.Run(base::File::FILE_ERROR_FAILED);
+    return;
+  }
+  if (path_to_watcher_id_.count(path)) {
+    // Multiple watchers have been installed on the same file path in a race.
+    // Following the contract of WatcherManager, we reject all except the first.
+    file_system_operation_runner_util::RemoveWatcherOnIOThread(
+        watcher_id, base::Bind(&ArcDocumentsProviderRoot::AddWatcherAborted,
+                               weak_ptr_factory_.GetWeakPtr(), callback));
+    return;
+  }
+  path_to_watcher_id_.insert(std::make_pair(path, watcher_id));
+  callback.Run(base::File::FILE_OK);
+}
+
+void ArcDocumentsProviderRoot::AddWatcherAborted(const StatusCallback& callback,
+                                                 bool success) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  callback.Run(base::File::FILE_ERROR_FAILED);
+}
+
+void ArcDocumentsProviderRoot::RemoveWatcherDone(const StatusCallback& callback,
+                                                 bool success) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  callback.Run(success ? base::File::FILE_OK : base::File::FILE_ERROR_FAILED);
+}
+
 void ArcDocumentsProviderRoot::ResolveToContentUrlWithDocumentId(
     const ResolveToContentUrlCallback& callback,
     const std::string& document_id) {