1 files changed, 86 insertions, 0 deletions
diff --git a/file_io/win32/flock.c b/file_io/win32/flock.c
new file mode 100644
index 0000000..e08e08a
--- /dev/null
+++ b/file_io/win32/flock.c
@@ -0,0 +1,86 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "apr_arch_file_io.h"
+
+APR_DECLARE(apr_status_t) apr_file_lock(apr_file_t *thefile, int type)
+{
+#ifdef _WIN32_WCE
+    /* The File locking is unsuported on WCE */
+    return APR_ENOTIMPL;
+#else
+    const DWORD len = 0xffffffff;
+    DWORD flags; 
+
+    flags = ((type & APR_FLOCK_NONBLOCK) ? LOCKFILE_FAIL_IMMEDIATELY : 0)
+          + (((type & APR_FLOCK_TYPEMASK) == APR_FLOCK_SHARED) 
+                                       ? 0 : LOCKFILE_EXCLUSIVE_LOCK);
+    if (apr_os_level >= APR_WIN_NT) {
+        /* Syntax is correct, len is passed for LengthLow and LengthHigh*/
+        OVERLAPPED offset;
+        memset (&offset, 0, sizeof(offset));
+        if (!LockFileEx(thefile->filehand, flags, 0, len, len, &offset))
+            return apr_get_os_error();
+    }
+    else {
+        /* On Win9x, LockFile() never blocks.  Hack in a crufty poll.
+         *
+         * Note that this hack exposes threads to being unserviced forever,
+         * in the situation that the given lock has low availability.
+         * When implemented in the kernel, LockFile will typically use
+         * FIFO or round robin distribution to ensure all threads get 
+         * one crack at the lock; but in this case we can't emulate that.
+         *
+         * However Win9x are barely maintainable anyways, if the user does
+         * choose to build to them, this is the best we can do.
+         */
+        while (!LockFile(thefile->filehand, 0, 0, len, 0)) {
+            DWORD err = GetLastError();
+            if ((err == ERROR_LOCK_VIOLATION) && !(type & APR_FLOCK_NONBLOCK))
+            {
+                Sleep(500); /* pause for a half second */
+                continue;   /* ... and then poll again */
+            }
+            return APR_FROM_OS_ERROR(err);
+        }
+    }
+
+    return APR_SUCCESS;
+#endif /* !defined(_WIN32_WCE) */
+}
+
+APR_DECLARE(apr_status_t) apr_file_unlock(apr_file_t *thefile)
+{
+#ifdef _WIN32_WCE
+    return APR_ENOTIMPL;
+#else
+    DWORD len = 0xffffffff;
+
+    if (apr_os_level >= APR_WIN_NT) {
+        /* Syntax is correct, len is passed for LengthLow and LengthHigh*/
+        OVERLAPPED offset;
+        memset (&offset, 0, sizeof(offset));
+        if (!UnlockFileEx(thefile->filehand, 0, len, len, &offset))
+            return apr_get_os_error();
+    }
+    else {
+        if (!UnlockFile(thefile->filehand, 0, 0, len, 0))
+            return apr_get_os_error();
+    }
+
+    return APR_SUCCESS;
+#endif /* !defined(_WIN32_WCE) */
+}