1 files changed, 121 insertions, 0 deletions
diff --git a/src/windows/identity/util/sync.c b/src/windows/identity/util/sync.c
new file mode 100644
index 0000000..b50d484
--- /dev/null
+++ b/src/windows/identity/util/sync.c
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2004 Massachusetts Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+/* $Id$ */
+
+#include<windows.h>
+#include<sync.h>
+#include<assert.h>
+
+#define LOCK_OPEN 0
+#define LOCK_READING 1
+#define LOCK_WRITING 2
+
+KHMEXP void KHMAPI InitializeRwLock(PRWLOCK pLock)
+{
+    pLock->locks = 0;
+    pLock->status = LOCK_OPEN;
+    InitializeCriticalSection(&(pLock->cs));
+    pLock->writewx = CreateEvent(NULL, 
+                                 FALSE, /* Manual reset */
+                                 TRUE,  /* Initial state */
+                                 NULL);
+    pLock->readwx = CreateEvent(NULL,
+                                TRUE, /* Manual reset */
+                                TRUE, /* Initial state */
+                                NULL);
+}
+
+KHMEXP void KHMAPI DeleteRwLock(PRWLOCK pLock)
+{
+    DeleteCriticalSection(&(pLock->cs));
+    CloseHandle(pLock->readwx);
+    CloseHandle(pLock->writewx);
+}
+
+KHMEXP void KHMAPI LockObtainRead(PRWLOCK pLock)
+{
+    while(1) {
+        WaitForSingleObject(pLock->readwx, INFINITE);
+        EnterCriticalSection(&pLock->cs);
+        if(pLock->status == LOCK_WRITING) {
+            LeaveCriticalSection(&(pLock->cs));
+            continue;
+        } else
+            break;
+    }
+    pLock->locks ++;
+    pLock->status = LOCK_READING;
+    ResetEvent(pLock->writewx);
+    LeaveCriticalSection(&(pLock->cs));
+}
+
+KHMEXP void KHMAPI LockReleaseRead(PRWLOCK pLock)
+{
+    EnterCriticalSection(&(pLock->cs));
+    assert(pLock->status == LOCK_READING);
+    pLock->locks--;
+    if(!pLock->locks) {
+        pLock->status = LOCK_OPEN;
+        SetEvent(pLock->readwx);
+        SetEvent(pLock->writewx);
+    }
+    LeaveCriticalSection(&(pLock->cs));
+}
+
+KHMEXP void KHMAPI LockObtainWrite(PRWLOCK pLock)
+{
+    EnterCriticalSection(&(pLock->cs));
+    if(pLock->status == LOCK_WRITING && 
+       pLock->writer == GetCurrentThreadId()) {
+        pLock->locks++;
+        LeaveCriticalSection(&(pLock->cs));
+        return;
+    }
+    LeaveCriticalSection(&(pLock->cs));
+    while(1) {
+        WaitForSingleObject(pLock->writewx, INFINITE);
+        EnterCriticalSection(&(pLock->cs));
+        if(pLock->status == LOCK_OPEN)
+            break;
+        LeaveCriticalSection(&(pLock->cs));
+    }
+    pLock->status = LOCK_WRITING;
+    pLock->locks++;
+    ResetEvent(pLock->readwx);
+    LeaveCriticalSection(&(pLock->cs));
+}
+
+KHMEXP void KHMAPI LockReleaseWrite(PRWLOCK pLock)
+{
+    EnterCriticalSection(&(pLock->cs));
+    assert(pLock->status == LOCK_WRITING);
+    pLock->locks--;
+    if(!pLock->locks) {
+        pLock->status = LOCK_OPEN;
+        SetEvent(pLock->readwx);
+        SetEvent(pLock->writewx);
+    }
+    LeaveCriticalSection(&(pLock->cs));
+}