Robert Shearman : ntdll: Add an optimisation for NtQueryDirectoryFile to not read the

[Alexandre Julliard]

Module: wine
Branch: refs/heads/master
Commit: f5cc0f7d09a1e6a89c9a5754d42884065d53aca0
URL:    http://source.winehq.org/git/?p=wine.git;a=commit;h=f5cc0f7d09a1e6a89c9a5754d42884065d53aca0

Author: Robert Shearman <rob at codeweavers.com>
Date:   Thu Aug  3 20:25:28 2006 +0100

ntdll: Add an optimisation for NtQueryDirectoryFile to not read the
whole directory if the mask doesn't contain any wildcards and the file
exists on in the directory with the same case as the mask.

---

 dlls/ntdll/directory.c |   81 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 78 insertions(+), 3 deletions(-)

diff --git a/dlls/ntdll/directory.c b/dlls/ntdll/directory.c
index faeca6c..47d018a 100644
--- a/dlls/ntdll/directory.c
+++ b/dlls/ntdll/directory.c
@@ -1126,6 +1126,74 @@ static void read_directory_readdir( int 
     else io->u.Status = restart_scan ? STATUS_NO_SUCH_FILE : STATUS_NO_MORE_FILES;
 }
 
+/***********************************************************************
+ *           read_directory_stat
+ *
+ * Read a single file from a directory by determining whether the file
+ * identified by mask exists using stat.
+ */
+static int read_directory_stat( int fd, IO_STATUS_BLOCK *io, void *buffer, ULONG length,
+                                BOOLEAN single_entry, const UNICODE_STRING *mask,
+                                BOOLEAN restart_scan )
+{
+    int unix_len, ret, used_default;
+    char *unix_name;
+    struct stat st;
+
+    TRACE("trying optimisation for file %s\n", debugstr_us( mask ));
+
+    unix_len = ntdll_wcstoumbs( 0, mask->Buffer, mask->Length / sizeof(WCHAR), NULL, 0, NULL, NULL );
+    if (!(unix_name = RtlAllocateHeap( GetProcessHeap(), 0, unix_len )))
+    {
+        io->u.Status = STATUS_NO_MEMORY;
+        return 0;
+    }
+    ret = ntdll_wcstoumbs( 0, mask->Buffer, mask->Length / sizeof(WCHAR), unix_name, unix_len,
+                           NULL, &used_default );
+    if (ret > 0 && !used_default)
+    {
+        if (restart_scan)
+        {
+            lseek( fd, 0, SEEK_SET );
+        }
+        else if (lseek( fd, 0, SEEK_CUR ) != 0)
+        {
+            io->u.Status = STATUS_NO_MORE_FILES;
+            ret = 0;
+            goto done;
+        }
+
+        ret = stat( unix_name, &st );
+        if (!ret)
+        {
+            FILE_BOTH_DIR_INFORMATION *info = append_entry( buffer, &io->Information, length, unix_name, NULL, mask );
+            if (info)
+            {
+                info->NextEntryOffset = 0;
+                if ((char *)info->FileName + info->FileNameLength > (char *)buffer + length)
+                    io->u.Status = STATUS_BUFFER_OVERFLOW;
+                else
+                    lseek( fd, 1, SEEK_CUR );
+            }
+        }
+    }
+    else ret = -1;
+
+done:
+    RtlFreeHeap( GetProcessHeap(), 0, unix_name );
+
+    TRACE("returning %d\n", ret);
+
+    return ret;
+}
+
+
+static inline WCHAR *mempbrkW( const WCHAR *ptr, const WCHAR *accept, size_t n )
+{
+    const WCHAR *end;
+    for (end = ptr + n; ptr < end; ptr++) if (strchrW( accept, *ptr )) return (WCHAR *)ptr;
+    return NULL;
+}
 
 /******************************************************************************
  *  NtQueryDirectoryFile	[NTDLL.@]
@@ -1141,6 +1209,7 @@ NTSTATUS WINAPI NtQueryDirectoryFile( HA
                                       BOOLEAN restart_scan )
 {
     int cwd, fd;
+    static const WCHAR wszWildcards[] = { '*','?',0 };
 
     TRACE("(%p %p %p %p %p %p 0x%08lx 0x%08x 0x%08x %s 0x%08x\n",
           handle, event, apc_routine, apc_context, io, buffer,
@@ -1171,14 +1240,20 @@ NTSTATUS WINAPI NtQueryDirectoryFile( HA
 
     if ((cwd = open(".", O_RDONLY)) != -1 && fchdir( fd ) != -1)
     {
+        if (mask && !mempbrkW( mask->Buffer, wszWildcards, mask->Length / sizeof(WCHAR) ) &&
+            read_directory_stat( fd, io, buffer, length, single_entry, mask, restart_scan ) != -1)
+            goto done;
 #ifdef VFAT_IOCTL_READDIR_BOTH
-        if ((read_directory_vfat( fd, io, buffer, length, single_entry, mask, restart_scan )) == -1)
+        if ((read_directory_vfat( fd, io, buffer, length, single_entry, mask, restart_scan )) != -1)
+            goto done;
 #endif
 #ifdef USE_GETDENTS
-            if ((read_directory_getdents( fd, io, buffer, length, single_entry, mask, restart_scan )) == -1)
+        if ((read_directory_getdents( fd, io, buffer, length, single_entry, mask, restart_scan )) != -1)
+            goto done;
 #endif
-                read_directory_readdir( fd, io, buffer, length, single_entry, mask, restart_scan );
+        read_directory_readdir( fd, io, buffer, length, single_entry, mask, restart_scan );
 
+    done:
         if (fchdir( cwd ) == -1) chdir( "/" );
     }
     else io->u.Status = FILE_GetNtStatus();