1 files changed, 435 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/xpcom/threads/nsAutoLock.cpp b/src/libs/xpcom18a4/xpcom/threads/nsAutoLock.cpp
new file mode 100644
index 00000000..df89408c
--- /dev/null
+++ b/src/libs/xpcom18a4/xpcom/threads/nsAutoLock.cpp
@@ -0,0 +1,435 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (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.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is mozilla.org code.
+ *
+ * The Initial Developer of the Original Code is
+ * Netscape Communications Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 1998
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "nsAutoLock.h"
+
+#ifdef DEBUG
+
+#include "plhash.h"
+#include "prprf.h"
+#include "prlock.h"
+#include "prthread.h"
+#include "nsDebug.h"
+#include "nsVoidArray.h"
+
+#ifdef NS_TRACE_MALLOC_XXX
+# include <stdio.h>
+# include "nsTraceMalloc.h"
+#endif
+
+static PRUintn      LockStackTPI = (PRUintn)-1;
+static PLHashTable* OrderTable = 0;
+static PRLock*      OrderTableLock = 0;
+
+static const char* const LockTypeNames[] = {"Lock", "Monitor", "CMonitor"};
+
+struct nsNamedVector : public nsVoidArray {
+    const char* mName;
+
+#ifdef NS_TRACE_MALLOC_XXX
+    // Callsites for the inner locks/monitors stored in our base nsVoidArray.
+    // This array parallels our base nsVoidArray.
+    nsVoidArray mInnerSites;
+#endif
+
+    nsNamedVector(const char* name = 0, PRUint32 initialSize = 0)
+        : nsVoidArray(initialSize),
+          mName(name)
+    {
+    }
+};
+
+static void * PR_CALLBACK
+_hash_alloc_table(void *pool, PRSize size)
+{
+    return operator new(size);
+}
+
+static void  PR_CALLBACK
+_hash_free_table(void *pool, void *item)
+{
+    operator delete(item);
+}
+
+static PLHashEntry * PR_CALLBACK
+_hash_alloc_entry(void *pool, const void *key)
+{
+    return new PLHashEntry;
+}
+
+/*
+ * Because monitors and locks may be associated with an nsAutoLockBase,
+ * without having had their associated nsNamedVector created explicitly in
+ * nsAutoMonitor::NewMonitor/DeleteMonitor, we need to provide a freeEntry
+ * PLHashTable hook, to avoid leaking nsNamedVectors which are replaced by
+ * nsAutoMonitor::NewMonitor.
+ *
+ * There is still a problem with the OrderTable containing orphaned
+ * nsNamedVector entries, for manually created locks wrapped by nsAutoLocks.
+ * (there should be no manually created monitors wrapped by nsAutoMonitors:
+ * you should use nsAutoMonitor::NewMonitor and nsAutoMonitor::DestroyMonitor
+ * instead of PR_NewMonitor and PR_DestroyMonitor).  These lock vectors don't
+ * strictly leak, as they are killed on shutdown, but there are unnecessary
+ * named vectors in the hash table that outlive their associated locks.
+ *
+ * XXX so we should have nsLock, nsMonitor, etc. and strongly type their
+ * XXX nsAutoXXX counterparts to take only the non-auto types as inputs
+ */
+static void  PR_CALLBACK
+_hash_free_entry(void *pool, PLHashEntry *entry, PRUintn flag)
+{
+    nsNamedVector* vec = (nsNamedVector*) entry->value;
+    if (vec) {
+        entry->value = 0;
+        delete vec;
+    }
+    if (flag == HT_FREE_ENTRY)
+        delete entry;
+}
+
+static const PLHashAllocOps _hash_alloc_ops = {
+    _hash_alloc_table, _hash_free_table,
+    _hash_alloc_entry, _hash_free_entry
+};
+
+PR_STATIC_CALLBACK(PRIntn)
+_purge_one(PLHashEntry* he, PRIntn cnt, void* arg)
+{
+    nsNamedVector* vec = (nsNamedVector*) he->value;
+
+    if (he->key == arg)
+        return HT_ENUMERATE_REMOVE;
+    vec->RemoveElement(arg);
+    return HT_ENUMERATE_NEXT;
+}
+
+PR_STATIC_CALLBACK(void)
+OnMonitorRecycle(void* addr)
+{
+    PR_Lock(OrderTableLock);
+    PL_HashTableEnumerateEntries(OrderTable, _purge_one, addr);
+    PR_Unlock(OrderTableLock);
+}
+
+PR_STATIC_CALLBACK(PLHashNumber)
+_hash_pointer(const void* key)
+{
+    return PLHashNumber(NS_PTR_TO_INT32(key)) >> 2;
+}
+
+// Must be single-threaded here, early in primordial thread.
+static void InitAutoLockStatics()
+{
+    (void) PR_NewThreadPrivateIndex(&LockStackTPI, 0);
+    OrderTable = PL_NewHashTable(64, _hash_pointer,
+                                 PL_CompareValues, PL_CompareValues,
+                                 &_hash_alloc_ops, 0);
+    if (OrderTable && !(OrderTableLock = PR_NewLock())) {
+        PL_HashTableDestroy(OrderTable);
+        OrderTable = 0;
+    }
+    PR_CSetOnMonitorRecycle(OnMonitorRecycle);
+}
+
+void _FreeAutoLockStatics()
+{
+    PLHashTable* table = OrderTable;
+    if (!table) return;
+
+    // Called at shutdown, so we don't need to lock.
+    PR_CSetOnMonitorRecycle(0);
+    PR_DestroyLock(OrderTableLock);
+    OrderTableLock = 0;
+    PL_HashTableDestroy(table);
+    OrderTable = 0;
+}
+
+static nsNamedVector* GetVector(PLHashTable* table, const void* key)
+{
+    PLHashNumber hash = _hash_pointer(key);
+    PLHashEntry** hep = PL_HashTableRawLookup(table, hash, key);
+    PLHashEntry* he = *hep;
+    if (he)
+        return (nsNamedVector*) he->value;
+    nsNamedVector* vec = new nsNamedVector();
+    if (vec)
+        PL_HashTableRawAdd(table, hep, hash, key, vec);
+    return vec;
+}
+
+// We maintain an acyclic graph in OrderTable, so recursion can't diverge.
+static PRBool Reachable(PLHashTable* table, const void* goal, const void* start)
+{
+    PR_ASSERT(goal);
+    PR_ASSERT(start);
+    nsNamedVector* vec = GetVector(table, start);
+    for (PRUint32 i = 0, n = vec->Count(); i < n; i++) {
+        void* addr = vec->ElementAt(i);
+        if (addr == goal || Reachable(table, goal, addr))
+            return PR_TRUE;
+    }
+    return PR_FALSE;
+}
+
+static PRBool WellOrdered(const void* addr1, const void* addr2,
+                          const void *callsite2, PRUint32* index2p,
+                          nsNamedVector** vec1p, nsNamedVector** vec2p)
+{
+    PRBool rv = PR_TRUE;
+    PLHashTable* table = OrderTable;
+    if (!table) return rv;
+    PR_Lock(OrderTableLock);
+
+    // Check whether we've already asserted (addr1 < addr2).
+    nsNamedVector* vec1 = GetVector(table, addr1);
+    if (vec1) {
+        PRUint32 i, n;
+
+        for (i = 0, n = vec1->Count(); i < n; i++)
+            if (vec1->ElementAt(i) == addr2)
+                break;
+
+        if (i == n) {
+            // Now check for (addr2 < addr1) and return false if so.
+            nsNamedVector* vec2 = GetVector(table, addr2);
+            if (vec2) {
+                for (i = 0, n = vec2->Count(); i < n; i++) {
+                    void* addri = vec2->ElementAt(i);
+                    PR_ASSERT(addri);
+                    if (addri == addr1 || Reachable(table, addr1, addri)) {
+                        *index2p = i;
+                        *vec1p = vec1;
+                        *vec2p = vec2;
+                        rv = PR_FALSE;
+                        break;
+                    }
+                }
+
+                if (rv) {
+                    // Assert (addr1 < addr2) into the order table.
+                    // XXX fix plvector/nsVector to use const void*
+                    vec1->AppendElement((void*) addr2);
+#ifdef NS_TRACE_MALLOC_XXX
+                    vec1->mInnerSites.AppendElement((void*) callsite2);
+#endif
+                }
+            }
+        }
+    }
+
+    PR_Unlock(OrderTableLock);
+    return rv;
+}
+
+nsAutoLockBase::nsAutoLockBase(void* addr, nsAutoLockType type)
+{
+    if (LockStackTPI == PRUintn(-1))
+        InitAutoLockStatics();
+
+    nsAutoLockBase* stackTop =
+        (nsAutoLockBase*) PR_GetThreadPrivate(LockStackTPI);
+    if (stackTop) {
+        if (stackTop->mAddr == addr) {
+            // Ignore reentry: it's legal for monitors, and NSPR will assert
+            // if you reenter a PRLock.
+        } else if (!addr) {
+            // Ignore null addresses: the caller promises not to use the
+            // lock at all, and NSPR will assert if you enter it.
+        } else {
+            const void* node =
+#ifdef NS_TRACE_MALLOC_XXX
+                NS_GetStackTrace(1)
+#else
+                nsnull
+#endif
+                ;
+            nsNamedVector* vec1;
+            nsNamedVector* vec2;
+            PRUint32 i2;
+
+            if (!WellOrdered(stackTop->mAddr, addr, node, &i2, &vec1, &vec2)) {
+                char buf[128];
+                PR_snprintf(buf, sizeof buf,
+                            "Potential deadlock between %s%s@%p and %s%s@%p",
+                            vec1->mName ? vec1->mName : "",
+                            LockTypeNames[stackTop->mType],
+                            stackTop->mAddr,
+                            vec2->mName ? vec2->mName : "",
+                            LockTypeNames[type],
+                            addr);
+#ifdef NS_TRACE_MALLOC_XXX
+                fprintf(stderr, "\n*** %s\n\nCurrent stack:\n", buf);
+                NS_DumpStackTrace(node, stderr);
+
+                fputs("\nPrevious stack:\n", stderr);
+                NS_DumpStackTrace(vec2->mInnerSites.ElementAt(i2), stderr);
+                putc('\n', stderr);
+#endif
+                NS_ERROR(buf);
+            }
+        }
+    }
+
+    mAddr = addr;
+    mDown = stackTop;
+    mType = type;
+    if (mAddr)
+        (void) PR_SetThreadPrivate(LockStackTPI, this);
+}
+
+nsAutoLockBase::~nsAutoLockBase()
+{
+    if (mAddr)
+        (void) PR_SetThreadPrivate(LockStackTPI, mDown);
+}
+
+void nsAutoLockBase::Show()
+{
+    if (!mAddr)
+        return;
+    nsAutoLockBase* curr = (nsAutoLockBase*) PR_GetThreadPrivate(LockStackTPI);
+    nsAutoLockBase* prev = nsnull;
+    while (curr != mDown) {
+        prev = curr;
+        curr = prev->mDown;
+    }
+    if (!prev)
+        PR_SetThreadPrivate(LockStackTPI, this);
+    else
+        prev->mDown = this;
+}
+
+void nsAutoLockBase::Hide()
+{
+    if (!mAddr)
+        return;
+    nsAutoLockBase* curr = (nsAutoLockBase*) PR_GetThreadPrivate(LockStackTPI);
+    nsAutoLockBase* prev = nsnull;
+    while (curr != this) {
+        prev = curr;
+        curr = prev->mDown;
+    }
+    if (!prev)
+        PR_SetThreadPrivate(LockStackTPI, mDown);
+    else
+        prev->mDown = mDown;
+}
+
+#endif /* DEBUG */
+
+PRMonitor* nsAutoMonitor::NewMonitor(const char* name)
+{
+    PRMonitor* mon = PR_NewMonitor();
+#ifdef DEBUG
+    if (mon && OrderTable) {
+        nsNamedVector* value = new nsNamedVector(name);
+        if (value) {
+            PR_Lock(OrderTableLock);
+            PL_HashTableAdd(OrderTable, mon, value);
+            PR_Unlock(OrderTableLock);
+        }
+    }
+#endif
+    return mon;
+}
+
+void nsAutoMonitor::DestroyMonitor(PRMonitor* mon)
+{
+#ifdef DEBUG
+    if (OrderTable)
+        OnMonitorRecycle(mon);
+#endif
+    PR_DestroyMonitor(mon);
+}
+
+void nsAutoMonitor::Enter()
+{
+#ifdef DEBUG
+    if (!mAddr) {
+        NS_ERROR("It is not legal to enter a null monitor");
+        return;
+    }
+    nsAutoLockBase* stackTop =
+        (nsAutoLockBase*) PR_GetThreadPrivate(LockStackTPI);
+    NS_ASSERTION(stackTop == mDown, "non-LIFO nsAutoMonitor::Enter");
+    mDown = stackTop;
+    (void) PR_SetThreadPrivate(LockStackTPI, this);
+#endif
+    PR_EnterMonitor(mMonitor);
+    mLockCount += 1;
+}
+
+void nsAutoMonitor::Exit()
+{
+#ifdef DEBUG
+    if (!mAddr) {
+        NS_ERROR("It is not legal to exit a null monitor");
+        return;
+    }
+    (void) PR_SetThreadPrivate(LockStackTPI, mDown);
+#endif
+    PRStatus status = PR_ExitMonitor(mMonitor);
+    NS_ASSERTION(status == PR_SUCCESS, "PR_ExitMonitor failed");
+    mLockCount -= 1;
+}
+
+// XXX we don't worry about cached monitors being destroyed behind our back.
+// XXX current NSPR (mozilla/nsprpub/pr/src/threads/prcmon.c) never destroys
+// XXX a cached monitor! potential resource pig in conjunction with necko...
+
+void nsAutoCMonitor::Enter()
+{
+#ifdef DEBUG
+    nsAutoLockBase* stackTop =
+        (nsAutoLockBase*) PR_GetThreadPrivate(LockStackTPI);
+    NS_ASSERTION(stackTop == mDown, "non-LIFO nsAutoCMonitor::Enter");
+    mDown = stackTop;
+    (void) PR_SetThreadPrivate(LockStackTPI, this);
+#endif
+    PR_CEnterMonitor(mLockObject);
+    mLockCount += 1;
+}
+
+void nsAutoCMonitor::Exit()
+{
+#ifdef DEBUG
+    (void) PR_SetThreadPrivate(LockStackTPI, mDown);
+#endif
+    PRStatus status = PR_CExitMonitor(mLockObject);
+    NS_ASSERTION(status == PR_SUCCESS, "PR_CExitMonitor failed");
+    mLockCount -= 1;
+}