Refactoring and tests for the highly undertested file_util::CreateOrUpdateShortcutLink() method.

base/win/shortcut.h

Index: base/win/shortcut.h
diff --git a/base/win/shortcut.h b/base/win/shortcut.h
new file mode 100644
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+++ b/base/win/shortcut.h
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+// 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.
+
+#ifndef BASE_WIN_SHORTCUT_H_
+#define BASE_WIN_SHORTCUT_H_
+
+#include <windows.h>
+
+#include "base/logging.h"
+#include "base/file_path.h"
+#include "base/string16.h"
+
+namespace base {
+namespace win {
+
+enum ShortcutOperation {
+  // Create a new shortcut (overwriting if necessary).
+  SHORTCUT_CREATE_ALWAYS = 0,
+  // Update specified (non-null) properties only on an existing shortcut.
+  SHORTCUT_UPDATE_EXISTING,
+};
+
+// Properties for shortcuts. Properties set will be applied to the shortcut on
+// creation/update, others will be ignored.
+// Callers are encouraged to use the setters provided which take care of
+// setting |options| as desired.
+struct ShortcutProperties {
+  enum IndividualProperties {
+    PROPERTIES_TARGET = 1 << 0,
+    PROPERTIES_WORKING_DIR = 1 << 1,
+    PROPERTIES_ARGUMENTS = 1 << 2,
+    PROPERTIES_DESCRIPTION = 1 << 3,
+    PROPERTIES_ICON = 1 << 4,
+    PROPERTIES_APP_ID = 1 << 5,
+    PROPERTIES_DUAL_MODE = 1 << 6,
+  };
+
+  ShortcutProperties() : options(0U) {}
+
+  void set_target(const FilePath& target_in) {
+    target = target_in;
+    options |= PROPERTIES_TARGET;
+  }
+
+  void set_working_dir(const FilePath& working_dir_in) {
+    working_dir = working_dir_in;
+    options |= PROPERTIES_WORKING_DIR;
+  }
+
+  void set_arguments(const string16& arguments_in) {
+    // Size restriction as per MSDN at http://goo.gl/TJ7q5.
+    DCHECK(arguments_in.size() < MAX_PATH);
+    arguments = arguments_in;
+    options |= PROPERTIES_ARGUMENTS;
+  }
+
+  void set_description(const string16& description_in) {
+    // Size restriction as per MSDN at http://goo.gl/OdNQq.
+    DCHECK(description_in.size() < MAX_PATH);
+    description = description_in;
+    options |= PROPERTIES_DESCRIPTION;
+  }
+
+  void set_icon(const FilePath& icon_in, int icon_index_in) {
+    icon = icon_in;
+    icon_index = icon_index_in;
+    options |= PROPERTIES_ICON;
+  }
+
+  void set_app_id(const string16& app_id_in) {
+    app_id = app_id_in;
+    options |= PROPERTIES_APP_ID;
+  }
+
+  void set_dual_mode(bool dual_mode_in) {
+    dual_mode = dual_mode_in;
+    options |= PROPERTIES_DUAL_MODE;
+  }
+
+  // The target to launch from this shortcut. This is mandatory when creating
+  // a shortcut.
+  FilePath target;
+  // The name of the working directory when launching the shortcut.
+  FilePath working_dir;
+  // The arguments to be applied to |target| when launching from this shortcut.
+  // The length of this string must be less than MAX_PATH.
+  string16 arguments;
+  // The localized description of the shortcut.
+  // The length of this string must be less than MAX_PATH.
+  string16 description;
+  // The path to the icon (can be a dll or exe, in which case |icon_index| is
+  // the resource id).
+  FilePath icon;
+  int icon_index;
+  // The app model id for the shortcut (Win7+).
+  string16 app_id;
+  // Whether this is a dual mode shortcut (Win8+).
+  // For now this property can only be set to true (i.e. once set it cannot be
+  // unset).
+  // TODO (gab): Make it possible to set this property to false.
+  bool dual_mode;
+  // Bitfield made of IndividualProperties. Properties set in |options| will be
+  // set on the shortcut, others will be ignored.
+  uint32 options;
+};
+
+// This method creates (or updates) a shortcut link at |shortcut_path| using the
+// information given through |properties|.
+// Ensure you have initialized COM before calling into this function.
+// |operation|: a choice from the ShortcutOperation enum.
+// If |operation| is SHORTCUT_UPDATE_EXISTING and |shortcut_path| does not
+// exist, this method is a no-op and returns false.
+BASE_EXPORT bool CreateOrUpdateShortcutLink(
+    const FilePath& shortcut_path,
+    const ShortcutProperties& properties,
+    ShortcutOperation operation);
+
+// Resolve Windows shortcut (.LNK file)
+// This methods tries to resolve a shortcut .LNK file. The path of the shortcut
+// to resolve is in |shortcut_path|. If |target_path| is not NULL, the target
+// will be resolved and placed in |target_path|. If |args| is not NULL, the
+// arguments will be retrieved and placed in |args|. The function returns true
+// if all requested fields are found successfully.
+// Callers can safely use the same variable for both |shortcut_path| and
+// |target_path|.
+BASE_EXPORT bool ResolveShortcut(const FilePath& shortcut_path,
+                                 FilePath* target_path,
+                                 string16* args);
+
+// Pins a shortcut to the Windows 7 taskbar. The shortcut file must already
+// exist and be a shortcut that points to an executable.
+BASE_EXPORT bool TaskbarPinShortcutLink(const wchar_t* shortcut);
+
+// Unpins a shortcut from the Windows 7 taskbar. The shortcut must exist and
+// already be pinned to the taskbar.
+BASE_EXPORT bool TaskbarUnpinShortcutLink(const wchar_t* shortcut);
+
+}  // namespace win
+}  // namespace base
+
+#endif  // BASE_WIN_SHORTCUT_H_