Print Preview: Fix failure to save with long page title

ui/shell_dialogs/select_file_dialog.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 "ui/shell_dialogs/select_file_dialog.h"
 
 #include <stddef.h>
+#include <algorithm>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "ui/shell_dialogs/select_file_dialog_factory.h"
 #include "ui/shell_dialogs/select_file_policy.h"
 #include "ui/shell_dialogs/selected_file_info.h"
 
 namespace {
 
 // Optional dialog factory. Leaked.
 ui::SelectFileDialogFactory* dialog_factory_ = NULL;
 
+// Returns a file path with a base name at most 255 characters long. This
+// is the limit on Windows and Linux, and on Windows the system file
+// selection dialog will fail to open if the file name exceeds 255 characters.
+base::FilePath GetShortenedFilePath(const base::FilePath& path) {
+  base::FilePath filename = path.BaseName();
+  base::FilePath short_path = path;
+  const size_t kMaxNameLength = 255;
+  if (filename.value().length() <= kMaxNameLength)
+    return short_path;
+  base::FilePath::StringType extension = filename.FinalExtension();
+  filename = filename.RemoveFinalExtension();
+  // 1 for . plus 12 for longest known extension.
+  size_t max_extension_length = 13;
+  if (filename.value().length() < kMaxNameLength) {
+    max_extension_length = std::max(max_extension_length,
+                                    kMaxNameLength - filename.value().length());
+  }
+  if (extension.length() >= max_extension_length) {
+    // Take the last max_extension_length - 1 characters (save 1 character
+    // for the '.').
+    base::FilePath::StringType new_extension;

[Lei Zhang, 2017/04/13 21:13:44]

Just an idea: would this be clearer if we instead first trimmed |extension| down
via substr(). Then insert(0, 1, kExtensionSeparator) ? Thereby eliminating the
need for |new_extension|.

[rbpotter, 2017/04/13 21:48:37]

Don't need this if we truncate since FinalExtension()
has the leading .

+    new_extension.push_back(base::FilePath::kExtensionSeparator);
+    extension = new_extension.append(
+        extension.substr(extension.length() - max_extension_length + 1,

[Lei Zhang, 2017/04/13 21:13:44]

We should truncate the extension instead of taking the end portion.

[rbpotter, 2017/04/13 21:48:37]

Done.

+                         max_extension_length - 1));
+  }
+  short_path = path.DirName().Append(
+      filename.value().substr(0, kMaxNameLength - extension.length()));
+  short_path = short_path.AddExtension(extension);
+  return short_path;
+}
+
 }  // namespace
 
 namespace ui {
 
 SelectFileDialog::FileTypeInfo::FileTypeInfo()
     : include_all_files(false), allowed_paths(NATIVE_PATH) {}
 
 SelectFileDialog::FileTypeInfo::FileTypeInfo(const FileTypeInfo& other) =
     default;
 
@@ skipping 57 matching lines @@
 
     // Inform the listener that no file was selected.
     // Post a task rather than calling FileSelectionCanceled directly to ensure
     // that the listener is called asynchronously.
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE,
         base::Bind(&SelectFileDialog::CancelFileSelection, this, params));
     return;
   }
 
+  base::FilePath path = GetShortenedFilePath(default_path);
+
   // Call the platform specific implementation of the file selection dialog.
-  SelectFileImpl(type, title, default_path, file_types, file_type_index,
+  SelectFileImpl(type, title, path, file_types, file_type_index,
                  default_extension, owning_window, params);
 }
 
 bool SelectFileDialog::HasMultipleFileTypeChoices() {
   return HasMultipleFileTypeChoicesImpl();
 }
 
 SelectFileDialog::SelectFileDialog(Listener* listener,
                                    ui::SelectFilePolicy* policy)
     : listener_(listener),
       select_file_policy_(policy) {
   DCHECK(listener_);
 }
 
 SelectFileDialog::~SelectFileDialog() {}
 
 void SelectFileDialog::CancelFileSelection(void* params) {
   if (listener_)
     listener_->FileSelectionCanceled(params);
 }
 
 }  // namespace ui