Re: [PATCH v3 19/34] fsmonitor-fs-listen-win32: implement FSMonitor backend on Windows

> Hi Jeff,
> 
> 
> On Thu, 1 Jul 2021, Jeff Hostetler via GitGitGadget wrote:
> 
> Jeff Hostetler <jeffhost@microsoft.com>
> 
> the win32 backend to register a watch on the working tree
> irectory (recursively).  Also watch the <gitdir> if it is
> side the working tree.  And to collect path change notifications
> atches and publish.
> 
> -off-by: Jeff Hostetler <jeffhost@microsoft.com>
> 
> t/fsmonitor/fsmonitor-fs-listen-win32.c | 530 +++++++++++++++++++
> e changed, 530 insertions(+)
> 
>> diff --git a/compat/fsmonitor/fsmonitor-fs-listen-win32.c b/compat/fsmonitor/fsmonitor-fs-listen-win32.c
>> index 880446b49e3..d707d47a0d7 100644
>> --- a/compat/fsmonitor/fsmonitor-fs-listen-win32.c
>> +++ b/compat/fsmonitor/fsmonitor-fs-listen-win32.c
>> @@ -2,20 +2,550 @@
>> + [...]
>> +
>> +static struct one_watch *create_watch(struct fsmonitor_daemon_state *state,
>> +				      const char *path)
>> +{
>> +	struct one_watch *watch = NULL;
>> +	DWORD desired_access = FILE_LIST_DIRECTORY;
>> +	DWORD share_mode =
>> +		FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE;
>> +	HANDLE hDir;
>> +
>> +	hDir = CreateFileA(path,
>> +			   desired_access, share_mode, NULL, OPEN_EXISTING,
>> +			   FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
>> +			   NULL);
> 
> The `*A()` family of Win32 API functions disagree with Git in one very
> interesting aspect: Git always assumes UTF-8, while e.g. `CreateFileA()`
> will use the current Win32 locale to internally transform to wide
> characters and then call `CreateFileW()`.
> 
> This poses no problem when your locale is US American and your paths
> contain no non-ASCII characters.
> 
> In the Git for Windows bug tracker, it was reported that it _does_ cause
> problems when venturing outside such a cozy scenario (for full details,
> see https://github.com/git-for-windows/git/issues/3262)
> 
> I need this (and merged it before starting the process to release Git for
> Windows v2.32.0(2)) to fix that (could I ask you to integrate this in case
> a re-roll will become necessary?):
> 
> -- snipsnap --
> From: Johannes Schindelin <johannes.schindelin@gmx.de>
> Date: Mon, 5 Jul 2021 13:51:05 +0200
> Subject: [PATCH] fixup! fsmonitor-fs-listen-win32: implement FSMonitor backend
>   on Windows
> 
> Let's keep avoiding the `*A()` family of Win32 API functions because
> they are susceptible to incoherent encoding problems. In Git for
> Windows, we always assume paths to be UTF-8 encoded. Let's use the
> dedicated helper to convert such a path to the wide character version,
> and then use the `*W()` function instead.
> 
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---
>   compat/fsmonitor/fsmonitor-fs-listen-win32.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/compat/fsmonitor/fsmonitor-fs-listen-win32.c b/compat/fsmonitor/fsmonitor-fs-listen-win32.c
> index ba087b292df..3b42ab311d9 100644
> --- a/compat/fsmonitor/fsmonitor-fs-listen-win32.c
> +++ b/compat/fsmonitor/fsmonitor-fs-listen-win32.c
> @@ -111,8 +111,14 @@ static struct one_watch *create_watch(struct fsmonitor_daemon_state *state,
>   	DWORD share_mode =
>   		FILE_SHARE_WRITE | FILE_SHARE_READ | FILE_SHARE_DELETE;
>   	HANDLE hDir;
> +	wchar_t wpath[MAX_PATH];
> 
> -	hDir = CreateFileA(path,
> +	if (xutftowcs_path(wpath, path) < 0) {
> +		error(_("could not convert to wide characters: '%s'"), path);
> +		return NULL;
> +	}
> +
> +	hDir = CreateFileW(wpath,
>   			   desired_access, share_mode, NULL, OPEN_EXISTING,
>   			   FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED,
>   			   NULL);
> --
> 2.32.0.windows.1.15.gf1590a75e2d
>