Rename "CheckWritable" to "PrepareForWritableApp" to reflect the actual behavior.

The existing implementation in fact does not check whether the file is
writable or not (see below for the detail.)
Since the current behavior itself is fine for the use cases,
this CL renames the relevant functions, and refactors the implementation
so that the intent is clearer.

Existing implementation tries to open a file with CREATE|READ|WRITE flags
and verifies that the result is either FILE_OK or ALREADY_EXISTS.

This _succeeds_ when read-only file already existed at the location
because ALREADY_EXISTS error precedes write failure.
Considering the fact, it is essentially equivalent to open with OPEN_ALWAYS|READ
and comparing the result just against FILE_OK.

BUG=367028

Review URL: https://codereview.chromium.org/306073004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274485 0039d316-1c4b-4281-b951-d872f2087c98

apps/launcher.cc

@@ -46,7 +46,7 @@ namespace app_runtime = apps::api::app_runtime;
 
 using apps::file_handler_util::GrantedFileEntry;
 using content::BrowserThread;
-using extensions::app_file_handler_util::CheckWritableFiles;
+using extensions::app_file_handler_util::PrepareFilesForWritableApp;
 using extensions::app_file_handler_util::FileHandlerForId;
 using extensions::app_file_handler_util::FileHandlerCanHandleFile;
 using extensions::app_file_handler_util::FirstFileHandlerForFile;
@@ -114,7 +114,7 @@ class PlatformAppPathLauncher
     if (HasFileSystemWritePermission(extension_)) {
       std::vector<base::FilePath> paths;
       paths.push_back(file_path_);
-      CheckWritableFiles(
+      PrepareFilesForWritableApp(
           paths,
           profile_,
           false,

chrome/browser/chromeos/file_manager/filesystem_api_util.cc

@@ -171,7 +171,7 @@ void IsNonNativeLocalPathDirectory(
       base::Bind(&BoolCallbackAsFileErrorCallback, callback));
 }
 
-void PrepareNonNativeLocalPathWritableFile(
+void PrepareNonNativeLocalFileForWritableApp(
     Profile* profile,
     const base::FilePath& path,
     const base::Callback<void(bool)>& callback) {

chrome/browser/chromeos/file_manager/filesystem_api_util.h

@@ -40,9 +40,10 @@ void IsNonNativeLocalPathDirectory(
     const base::FilePath& path,
     const base::Callback<void(bool)>& callback);
 
-// Prepares a writable file at |path|, i.e., creates a file there if it didn't
-// exist, and asynchronously sends to |callback| whether it succeeded.
-void PrepareNonNativeLocalPathWritableFile(
+// Ensures a file exists at |path|, i.e., it does nothing if a file is already
+// present, or creates a file there if it isn't, and asynchronously sends to
+// |callback| whether it succeeded.
+void PrepareNonNativeLocalFileForWritableApp(
     Profile* profile,
     const base::FilePath& path,
     const base::Callback<void(bool)>& callback);

chrome/browser/extensions/api/file_handlers/app_file_handler_util.cc

@@ -77,12 +77,9 @@ bool DoCheckWritableFile(const base::FilePath& path, bool is_directory) {
     return base::DirectoryExists(path);
 
   // Create the file if it doesn't already exist.
-  int creation_flags = base::File::FLAG_CREATE | base::File::FLAG_READ |
-                       base::File::FLAG_WRITE;
+  int creation_flags = base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_READ;
   base::File file(path, creation_flags);
-  if (file.IsValid())
-    return true;
-  return file.error_details() == base::File::FILE_ERROR_EXISTS;
+  return file.IsValid();
 }
 
 // Checks whether a list of paths are all OK for writing and calls a provided
@@ -155,7 +152,7 @@ void WritableFileChecker::Check() {
             base::Bind(&WritableFileChecker::NonNativeLocalPathCheckDone,
                        this, *it));
       } else {
-        file_manager::util::PrepareNonNativeLocalPathWritableFile(
+        file_manager::util::PrepareNonNativeLocalFileForWritableApp(
             profile_,
             *it,
             base::Bind(&WritableFileChecker::NonNativeLocalPathCheckDone,
@@ -320,7 +317,7 @@ GrantedFileEntry CreateFileEntry(
   return result;
 }
 
-void CheckWritableFiles(
+void PrepareFilesForWritableApp(
     const std::vector<base::FilePath>& paths,
     Profile* profile,
     bool is_directory,

chrome/browser/extensions/api/file_handlers/app_file_handler_util.h

@@ -66,7 +66,12 @@ apps::file_handler_util::GrantedFileEntry CreateFileEntry(
     const base::FilePath& path,
     bool is_directory);
 
-void CheckWritableFiles(
+// When |is_directory| is true, it verifies that directories exist at each of
+// the |paths| and calls back to |on_success| or otherwise to |on_failure|.
+// When |is_directory| is false, it ensures regular files exists (not links and
+// directories) at the |paths|, creating files if needed, and calls back to
+// |on_success| or to |on_failure| depending on the result.
+void PrepareFilesForWritableApp(
     const std::vector<base::FilePath>& paths,
     Profile* profile,
     bool is_directory,

chrome/browser/extensions/api/file_system/file_system_api.cc

@@ -283,10 +283,10 @@ FileSystemEntryFunction::FileSystemEntryFunction()
       is_directory_(false),
       response_(NULL) {}
 
-void FileSystemEntryFunction::CheckWritableFiles(
+void FileSystemEntryFunction::PrepareFilesForWritableApp(
     const std::vector<base::FilePath>& paths) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
-  app_file_handler_util::CheckWritableFiles(
+  app_file_handler_util::PrepareFilesForWritableApp(
       paths,
       GetProfile(),
       is_directory_,
@@ -392,7 +392,7 @@ void FileSystemGetWritableEntryFunction::CheckPermissionAndSendResponse() {
   }
   std::vector<base::FilePath> paths;
   paths.push_back(path_);
-  CheckWritableFiles(paths);
+  PrepareFilesForWritableApp(paths);
 }
 
 void FileSystemGetWritableEntryFunction::SetIsDirectoryOnFileThread() {
@@ -770,7 +770,7 @@ void FileSystemChooseEntryFunction::ConfirmDirectoryAccessOnFileThread(
 void FileSystemChooseEntryFunction::OnDirectoryAccessConfirmed(
     const std::vector<base::FilePath>& paths) {
   if (app_file_handler_util::HasFileSystemWritePermission(extension_)) {
-    CheckWritableFiles(paths);
+    PrepareFilesForWritableApp(paths);
     return;
   }
 

chrome/browser/extensions/api/file_system/file_system_api.h

@@ -53,7 +53,7 @@ class FileSystemEntryFunction : public ChromeAsyncExtensionFunction {
   // will ensure the files exist, creating them if necessary, and also check
   // that none of the files are links. If it succeeds it proceeds to
   // RegisterFileSystemsAndSendResponse, otherwise to HandleWritableFileError.
-  void CheckWritableFiles(const std::vector<base::FilePath>& path);
+  void PrepareFilesForWritableApp(const std::vector<base::FilePath>& path);
 
   // This will finish the choose file process. This is either called directly
   // from FilesSelected, or from WritableFileChecker. It is called on the UI