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-rw-r--r--storage/SQLiteMutex.h143
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diff --git a/storage/SQLiteMutex.h b/storage/SQLiteMutex.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_storage_SQLiteMutex_h_
+#define mozilla_storage_SQLiteMutex_h_
+
+#include "mozilla/BlockingResourceBase.h"
+#include "sqlite3.h"
+
+namespace mozilla {
+namespace storage {
+
+/**
+ * Wrapper class for sqlite3_mutexes. To be used whenever we want to use a
+ * sqlite3_mutex.
+ *
+ * @warning Never EVER wrap the same sqlite3_mutex with a different SQLiteMutex.
+ * If you do this, you void the deadlock detector's warranty!
+ */
+class SQLiteMutex : private BlockingResourceBase {
+ public:
+ /**
+ * Constructs a wrapper for a sqlite3_mutex that has deadlock detecting.
+ *
+ * @param aName
+ * A name which can be used to reference this mutex.
+ */
+ explicit SQLiteMutex(const char* aName)
+ : BlockingResourceBase(aName, eMutex), mMutex(nullptr) {}
+
+ /**
+ * Sets the mutex that we are wrapping. We generally do not have access to
+ * our mutex at class construction, so we have to set it once we get access to
+ * it.
+ *
+ * @param aMutex
+ * The sqlite3_mutex that we are going to wrap.
+ */
+ void initWithMutex(sqlite3_mutex* aMutex) {
+ MOZ_ASSERT(aMutex, "You must pass in a valid mutex!");
+ MOZ_ASSERT(!mMutex, "A mutex has already been set for this!");
+ mMutex = aMutex;
+ }
+
+ /**
+ * After a connection has been successfully closed, its mutex is a dangling
+ * pointer, and as such it should be destroyed.
+ */
+ void destroy() { mMutex = NULL; }
+
+ /**
+ * Acquires the mutex.
+ */
+ void lock() {
+ MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+#if defined(DEBUG)
+ // While SQLite Mutexes may be recursive, in our own code we do not want to
+ // treat them as such.
+ CheckAcquire();
+#endif
+
+ ::sqlite3_mutex_enter(mMutex);
+
+#if defined(DEBUG)
+ Acquire(); // Call is protected by us holding the mutex.
+#endif
+ }
+
+ /**
+ * Releases the mutex.
+ */
+ void unlock() {
+ MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+#if defined(DEBUG)
+ // While SQLite Mutexes may be recursive, in our own code we do not want to
+ // treat them as such.
+ Release(); // Call is protected by us holding the mutex.
+#endif
+
+ ::sqlite3_mutex_leave(mMutex);
+ }
+
+ /**
+ * Asserts that the current thread owns the mutex.
+ */
+ void assertCurrentThreadOwns() {
+ MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+ MOZ_ASSERT(::sqlite3_mutex_held(mMutex),
+ "Mutex is not held, but we expect it to be!");
+ }
+
+ /**
+ * Asserts that the current thread does not own the mutex.
+ */
+ void assertNotCurrentThreadOwns() {
+ MOZ_ASSERT(mMutex, "No mutex associated with this wrapper!");
+ MOZ_ASSERT(::sqlite3_mutex_notheld(mMutex),
+ "Mutex is held, but we expect it to not be!");
+ }
+
+ private:
+ sqlite3_mutex* mMutex;
+};
+
+/**
+ * Automatically acquires the mutex when it enters scope, and releases it when
+ * it leaves scope.
+ */
+class MOZ_STACK_CLASS SQLiteMutexAutoLock {
+ public:
+ explicit SQLiteMutexAutoLock(SQLiteMutex& aMutex) : mMutex(aMutex) {
+ mMutex.lock();
+ }
+
+ ~SQLiteMutexAutoLock() { mMutex.unlock(); }
+
+ private:
+ SQLiteMutex& mMutex;
+};
+
+/**
+ * Automatically releases the mutex when it enters scope, and acquires it when
+ * it leaves scope.
+ */
+class MOZ_STACK_CLASS SQLiteMutexAutoUnlock {
+ public:
+ explicit SQLiteMutexAutoUnlock(SQLiteMutex& aMutex) : mMutex(aMutex) {
+ mMutex.unlock();
+ }
+
+ ~SQLiteMutexAutoUnlock() { mMutex.lock(); }
+
+ private:
+ SQLiteMutex& mMutex;
+};
+
+} // namespace storage
+} // namespace mozilla
+
+#endif // mozilla_storage_SQLiteMutex_h_