Implement fileSystem.chooseFile.

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

 // Copyright (c) 2012 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/extensions/api/file_system/file_system_api.h"
 
+#include "base/bind.h"
 #include "base/file_path.h"
+#include "base/file_util.h"
 #include "chrome/browser/extensions/shell_window_registry.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/ui/extensions/shell_window.h"
 #include "chrome/browser/ui/select_file_dialog.h"
+#include "chrome/common/extensions/api/file_system.h"
 #include "content/public/browser/child_process_security_policy.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
 #include "webkit/fileapi/file_system_util.h"
 #include "webkit/fileapi/isolated_context.h"
 
 const char kInvalidParameters[] = "Invalid parameters";
 const char kSecurityError[] = "Security error";
 const char kInvalidCallingPage[] = "Invalid calling page";
 const char kUserCancelled[] = "User cancelled";
+const char kWritableFileError[] = "Invalid file for writing";
+
+const char kSaveFileOption[] = "saveFile";
+
+namespace file_system = extensions::api::file_system;
+namespace ChooseFile = file_system::ChooseFile;
 
 namespace {
 
 bool GetFilePathOfFileEntry(const std::string& filesystem_name,
                             const std::string& filesystem_path,
                             const content::RenderViewHost* render_view_host,
                             FilePath* file_path,
                             std::string* error) {
   std::string filesystem_id;
   if (!fileapi::CrackIsolatedFileSystemName(filesystem_name, &filesystem_id)) {
@@ skipping 19 matching lines @@
                                   &filesystem_id,
                                   NULL,
                                   file_path)) {
     *error = kInvalidParameters;
     return false;
   }
 
   return true;
 }
 
+bool DoCheckWritableFile(const FilePath& path) {
+  // Don't allow links.
+  if (file_util::PathExists(path) && file_util::IsLink(path))
+    return false;
+
+  // Create the file if it doesn't already exist.
+  bool created = false;

[koz (OOO until 15th September), 2012/06/14 06:18:01]

This doesn't seem to be used, so you can remove it and pass NULL below.

[benwells, 2012/06/15 00:45:44]

Done. I also changed from CREATE_ALWAYS to CREATE, CREATE_ALWAYS is not needed.

+  base::PlatformFileError error = base::PLATFORM_FILE_OK;
+  int creation_flags = base::PLATFORM_FILE_CREATE_ALWAYS |
+                       base::PLATFORM_FILE_READ |
+                       base::PLATFORM_FILE_WRITE;
+  base::CreatePlatformFile(path, creation_flags, &created, &error);
+  return error == base::PLATFORM_FILE_OK;
+}
+
 }  // namespace
 
 namespace extensions {
 
 bool FileSystemGetDisplayPathFunction::RunImpl() {
   std::string filesystem_name;
   std::string filesystem_path;
   EXTENSION_FUNCTION_VALIDATE(args_->GetString(0, &filesystem_name));
   EXTENSION_FUNCTION_VALIDATE(args_->GetString(1, &filesystem_path));
 
   FilePath file_path;
   if (!GetFilePathOfFileEntry(filesystem_name, filesystem_path,
                               render_view_host_, &file_path, &error_)) {
     return false;
   }
 
   result_.reset(base::Value::CreateStringValue(file_path.value()));
   return true;
 }
 
 // Handles showing a dialog to the user to ask for the filename for a file to
 // save.
-class FileSystemGetWritableFileEntryFunction::FilePicker
-    : public SelectFileDialog::Listener {
+class FileSystemPickerFunction::FilePicker : public SelectFileDialog::Listener {
  public:
-  FilePicker(FileSystemGetWritableFileEntryFunction* function,
+  FilePicker(FileSystemPickerFunction* function,
              content::WebContents* web_contents,
-             const FilePath& suggested_path)
+             const FilePath& suggested_path,
+             bool for_save)
       : suggested_path_(suggested_path),
+        for_save_(for_save),
         function_(function) {
     select_file_dialog_ = SelectFileDialog::Create(this);
     SelectFileDialog::FileTypeInfo file_type_info;
     FilePath::StringType extension = suggested_path.Extension();
     if (!extension.empty()) {
       extension.erase(extension.begin());  // drop the .
       file_type_info.extensions.resize(1);
       file_type_info.extensions[0].push_back(extension);
     }
     file_type_info.include_all_files = true;
     gfx::NativeWindow owning_window = web_contents ?
         platform_util::GetTopLevel(web_contents->GetNativeView()) : NULL;
 
-    select_file_dialog_->SelectFile(SelectFileDialog::SELECT_SAVEAS_FILE,
+    select_file_dialog_->SelectFile(for_save ?
+                                        SelectFileDialog::SELECT_SAVEAS_FILE :
+                                        SelectFileDialog::SELECT_OPEN_FILE,
                                     string16(),
                                     suggested_path,
                                     &file_type_info, 0, FILE_PATH_LITERAL(""),
                                     web_contents, owning_window, NULL);
   }
 
   virtual ~FilePicker() {}
 
  private:
   // SelectFileDialog::Listener implementation.
   virtual void FileSelected(const FilePath& path,
                             int index,
                             void* params) OVERRIDE {
-    function_->FileSelected(path);
+    function_->FileSelected(path, for_save_);
     delete this;
   }
 
   virtual void FileSelectionCanceled(void* params) OVERRIDE {
     function_->FileSelectionCanceled();
     delete this;
   }
 
   FilePath suggested_path_;
+  bool for_save_;

[koz (OOO until 15th September), 2012/06/14 06:18:01]

Could you add a comment here?

[benwells, 2012/06/15 00:45:44]

Done.

 
-  // For managing select file dialogs.
   scoped_refptr<SelectFileDialog> select_file_dialog_;
-  scoped_refptr<FileSystemGetWritableFileEntryFunction> function_;
+  scoped_refptr<FileSystemPickerFunction> function_;
 
   DISALLOW_COPY_AND_ASSIGN(FilePicker);
 };
 
-bool FileSystemGetWritableFileEntryFunction::RunImpl() {
-  std::string filesystem_name;
-  std::string filesystem_path;
-  EXTENSION_FUNCTION_VALIDATE(args_->GetString(0, &filesystem_name));
-  EXTENSION_FUNCTION_VALIDATE(args_->GetString(1, &filesystem_path));
-
-  FilePath suggested_path;
-  if (!GetFilePathOfFileEntry(filesystem_name, filesystem_path,
-                              render_view_host_, &suggested_path, &error_)) {
-    return false;
-  }
-
+bool FileSystemPickerFunction::ShowPicker(const FilePath& suggested_path,
+                                          bool for_save) {
   ShellWindowRegistry* registry = ShellWindowRegistry::Get(profile());
   DCHECK(registry);
   ShellWindow* shell_window = registry->GetShellWindowForRenderViewHost(
       render_view_host());
   if (!shell_window) {
     error_ = kInvalidCallingPage;
     return false;
   }
 
   // The file picker will hold a reference to this function instance, preventing
   // its destruction (and subsequent sending of the function response) until the
   // user has selected a file or cancelled the picker. At that point, the picker
   // will delete itself, which will also free the function instance.
-  new FilePicker(this, shell_window->web_contents(), suggested_path);
+  new FilePicker(this, shell_window->web_contents(), suggested_path, for_save);
   return true;
 }
 
-void FileSystemGetWritableFileEntryFunction::FileSelected(
-    const FilePath& path) {
+void FileSystemPickerFunction::FileSelected(const FilePath& path,
+                                            bool for_save) {
+  if (for_save) {
+    content::BrowserThread::PostTask(content::BrowserThread::FILE, FROM_HERE,
+        base::Bind(&FileSystemPickerFunction::CheckWritableFile, this, path));
+    return;
+  }
+
+  // Don't need to check the file, it's for reading.
+  RegisterFileSystemAndSendResponse(path, false);
+}
+
+void FileSystemPickerFunction::FileSelectionCanceled() {
+  error_ = kUserCancelled;
+  SendResponse(false);
+}
+
+void FileSystemPickerFunction::CheckWritableFile(const FilePath& path) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::FILE));
+  if (DoCheckWritableFile(path)) {
+    content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+        base::Bind(&FileSystemPickerFunction::RegisterFileSystemAndSendResponse,
+            this, path, true));
+    return;
+  }
+
+  content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+      base::Bind(&FileSystemPickerFunction::HandleWritableFileError, this));
+}
+
+void FileSystemPickerFunction::RegisterFileSystemAndSendResponse(
+    const FilePath& path, bool for_save) {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   std::set<FilePath> filesets;
   filesets.insert(path);
 
   fileapi::IsolatedContext* isolated_context =
       fileapi::IsolatedContext::GetInstance();
   DCHECK(isolated_context);
   std::string filesystem_id = isolated_context->RegisterIsolatedFileSystem(
       filesets);
 
   content::ChildProcessSecurityPolicy* policy =
       content::ChildProcessSecurityPolicy::GetInstance();
   int renderer_id = render_view_host_->GetProcess()->GetID();
-  policy->GrantReadWriteFileSystem(renderer_id, filesystem_id);
+  if (for_save)
+    policy->GrantReadWriteFileSystem(renderer_id, filesystem_id);
+  else
+    policy->GrantReadFileSystem(renderer_id, filesystem_id);
+
+  // We only need file level access for reading FileEntries. Saving FileEntries
+  // just needs the file system to have read/write access, which is granted
+  // above if required.
+  if (!policy->CanReadFile(renderer_id, path))
+    policy->GrantReadFile(renderer_id, path);
 
   DictionaryValue* dict = new DictionaryValue();
   result_.reset(dict);
   dict->SetString("fileSystemId", filesystem_id);
   dict->SetString("baseName", path.BaseName().AsUTF8Unsafe());
   SendResponse(true);
 }
 
-void FileSystemGetWritableFileEntryFunction::FileSelectionCanceled() {
-  error_ = kUserCancelled;
+void FileSystemPickerFunction::HandleWritableFileError() {
+  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+  error_ = kWritableFileError;
   SendResponse(false);
 }
 
+bool FileSystemGetWritableFileEntryFunction::RunImpl() {
+  std::string filesystem_name;
+  std::string filesystem_path;
+  EXTENSION_FUNCTION_VALIDATE(args_->GetString(0, &filesystem_name));
+  EXTENSION_FUNCTION_VALIDATE(args_->GetString(1, &filesystem_path));
+
+  FilePath suggested_path;
+  if (!GetFilePathOfFileEntry(filesystem_name, filesystem_path,
+                              render_view_host_, &suggested_path, &error_)) {
+    return false;
+  }
+
+  return ShowPicker(suggested_path, true);
+}
+
+bool FileSystemChooseFileFunction::RunImpl() {
+  scoped_ptr<ChooseFile::Params> params(ChooseFile::Params::Create(*args_));
+  EXTENSION_FUNCTION_VALIDATE(params.get());
+
+  bool for_save = false;
+  file_system::ChooseFileOptions* options = params->options.get();
+  if (options) {
+    if (options->type.get() &&  *options->type == kSaveFileOption)
+      for_save = true;
+  }
+
+  return ShowPicker(FilePath(), for_save);
+}
+
 }  // namespace extensions