ShellUtil: Add generic methods to add/delete Windows file associations.

chrome/browser/file_associations_win.cc

Index: chrome/browser/file_associations_win.cc
diff --git a/chrome/browser/file_associations_win.cc b/chrome/browser/file_associations_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..38e9f7ec67c896efcd0d31140869c79eea099dd7
--- /dev/null
+++ b/chrome/browser/file_associations_win.cc
@@ -0,0 +1,45 @@
+// Copyright 2014 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/file_associations_win.h"
+
+#include <shlobj.h>

[grt (UTC plus 2), 2014/09/15 13:38:37]

i believe <windows.h> should always be included before all other windows-y
headers.

[Matt Giuca, 2014/09/16 07:29:13]

Done.

+
+#include "base/strings/utf_string_conversions.h"
+#include "chrome/installer/util/shell_util.h"
+
+bool AddWindowsFileAssociations(const std::string& progid,

[grt (UTC plus 2), 2014/09/15 13:38:37]

what will call this? why is |progid| a string rather than a string16? same
question for file_type_name.

[Matt Giuca, 2014/09/16 07:29:12]

I'm trying to abstract over the implementation details. Using std::string for
strings is standard practice throughout the Chromium code base, and they are
converted to string16 only when we need to interface with some Windows API.

The functions in shell_util don't follow this convention, so my functions there
take string16, but in this new module, it's best to follow the convention.
(Having said that, I might delete this module altogether depending on how simple
it ends up being -- right now it doesn't look worthwhile.)

[grt (UTC plus 2), 2014/09/16 13:34:56]

The reason I asked about the caller is that it would be unfortunate if the
source of the string for the caller is a UFT16 string that they have to convert
to UTF8 just so this code can switch it back. A prog_id is inherently a
Windows-y thing, so I don't see why the caller would want it in UTF8.

[Matt Giuca, 2014/09/18 00:07:04]

Yeah, that would be unfortunate, but not a huge problem and I think the design
is better if abstract interfaces like this are using the platform-neutral string
type. All the call sites I plan to use this with have a std::string because they
build it from platform-neutral sources (like extension manifest data).

+                                const base::CommandLine& command_line,

[grt (UTC plus 2), 2014/09/15 13:38:37]

#include "base/command_line.h"

[Matt Giuca, 2014/09/16 07:29:13]

I don't think this is needed because this file never touches the inside of a
CommandLine, only passes it on by reference to another function.

[grt (UTC plus 2), 2014/09/16 13:34:56]

Acknowledged.

+                                const std::string& file_type_name,
+                                const base::FilePath& icon_path,

[grt (UTC plus 2), 2014/09/15 13:38:37]

#include "base/files/file_path.h"

[Matt Giuca, 2014/09/16 07:29:13]

Same.

[grt (UTC plus 2), 2014/09/16 13:34:55]

Acknowledged.

+                                const std::set<std::string>& file_extensions) {
+  std::set<base::string16> file_extensions_16;

[grt (UTC plus 2), 2014/09/15 13:38:37]

#include "base/strings/string16.h"

[Matt Giuca, 2014/09/16 07:29:12]

Done.

+  for (std::set<std::string>::const_iterator it = file_extensions.begin();
+       it != file_extensions.end();
+       ++it) {
+    file_extensions_16.insert(base::UTF8ToUTF16(*it));
+  }
+  if (!ShellUtil::AddFileAssociations(base::UTF8ToUTF16(progid),
+                                      command_line,
+                                      base::UTF8ToUTF16(file_type_name),
+                                      icon_path,
+                                      file_extensions_16)) {
+    return false;
+  }
+
+  // Success. Tell Windows Explorer to update its cache.
+  SHChangeNotify(
+      SHCNE_ASSOCCHANGED, SHCNF_IDLIST | SHCNF_FLUSHNOWAIT, NULL, NULL);
+  return true;
+}
+
+bool DeleteWindowsFileAssociations(const std::string& progid) {
+  if (!ShellUtil::DeleteFileAssociations(base::UTF8ToUTF16(progid)))
+    return false;
+
+  // Success. Tell Windows Explorer to update its cache.
+  SHChangeNotify(
+      SHCNE_ASSOCCHANGED, SHCNF_IDLIST | SHCNF_FLUSHNOWAIT, NULL, NULL);
+  return true;
+}