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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/. */
#include <stdio.h>
#include "nsError.h"
#include "nsThreadUtils.h"
#include "nsIFile.h"
#include "nsIFileURL.h"
#include "nsIXPConnect.h"
#include "mozilla/Telemetry.h"
#include "mozilla/Mutex.h"
#include "mozilla/CondVar.h"
#include "mozilla/Attributes.h"
#include "mozilla/ErrorNames.h"
#include "mozilla/Unused.h"
#include "mozilla/dom/quota/QuotaObject.h"
#include "mozilla/ScopeExit.h"
#include "mozilla/SpinEventLoopUntil.h"
#include "mozilla/StaticPrefs_storage.h"
#include "mozIStorageCompletionCallback.h"
#include "mozIStorageFunction.h"
#include "mozStorageAsyncStatementExecution.h"
#include "mozStorageSQLFunctions.h"
#include "mozStorageConnection.h"
#include "mozStorageService.h"
#include "mozStorageStatement.h"
#include "mozStorageAsyncStatement.h"
#include "mozStorageArgValueArray.h"
#include "mozStoragePrivateHelpers.h"
#include "mozStorageStatementData.h"
#include "StorageBaseStatementInternal.h"
#include "SQLCollations.h"
#include "FileSystemModule.h"
#include "mozStorageHelper.h"
#include "mozilla/Logging.h"
#include "mozilla/Printf.h"
#include "mozilla/ProfilerLabels.h"
#include "nsProxyRelease.h"
#include "nsURLHelper.h"
#include <algorithm>
#define MIN_AVAILABLE_BYTES_PER_CHUNKED_GROWTH 524288000 // 500 MiB
// Maximum size of the pages cache per connection.
#define MAX_CACHE_SIZE_KIBIBYTES 2048 // 2 MiB
mozilla::LazyLogModule gStorageLog("mozStorage");
// Checks that the protected code is running on the main-thread only if the
// connection was also opened on it.
#ifdef DEBUG
# define CHECK_MAINTHREAD_ABUSE() \
do { \
nsCOMPtr<nsIThread> mainThread = do_GetMainThread(); \
NS_WARNING_ASSERTION( \
threadOpenedOn == mainThread || !NS_IsMainThread(), \
"Using Storage synchronous API on main-thread, but " \
"the connection was " \
"opened on another thread."); \
} while (0)
#else
# define CHECK_MAINTHREAD_ABUSE() \
do { /* Nothing */ \
} while (0)
#endif
namespace mozilla::storage {
using mozilla::dom::quota::QuotaObject;
using mozilla::Telemetry::AccumulateCategoricalKeyed;
using mozilla::Telemetry::LABELS_SQLITE_STORE_OPEN;
using mozilla::Telemetry::LABELS_SQLITE_STORE_QUERY;
const char* GetTelemetryVFSName(bool);
const char* GetObfuscatingVFSName();
namespace {
int nsresultToSQLiteResult(nsresult aXPCOMResultCode) {
if (NS_SUCCEEDED(aXPCOMResultCode)) {
return SQLITE_OK;
}
switch (aXPCOMResultCode) {
case NS_ERROR_FILE_CORRUPTED:
return SQLITE_CORRUPT;
case NS_ERROR_FILE_ACCESS_DENIED:
return SQLITE_CANTOPEN;
case NS_ERROR_STORAGE_BUSY:
return SQLITE_BUSY;
case NS_ERROR_FILE_IS_LOCKED:
return SQLITE_LOCKED;
case NS_ERROR_FILE_READ_ONLY:
return SQLITE_READONLY;
case NS_ERROR_STORAGE_IOERR:
return SQLITE_IOERR;
case NS_ERROR_FILE_NO_DEVICE_SPACE:
return SQLITE_FULL;
case NS_ERROR_OUT_OF_MEMORY:
return SQLITE_NOMEM;
case NS_ERROR_UNEXPECTED:
return SQLITE_MISUSE;
case NS_ERROR_ABORT:
return SQLITE_ABORT;
case NS_ERROR_STORAGE_CONSTRAINT:
return SQLITE_CONSTRAINT;
default:
return SQLITE_ERROR;
}
MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("Must return in switch above!");
}
////////////////////////////////////////////////////////////////////////////////
//// Variant Specialization Functions (variantToSQLiteT)
int sqlite3_T_int(sqlite3_context* aCtx, int aValue) {
::sqlite3_result_int(aCtx, aValue);
return SQLITE_OK;
}
int sqlite3_T_int64(sqlite3_context* aCtx, sqlite3_int64 aValue) {
::sqlite3_result_int64(aCtx, aValue);
return SQLITE_OK;
}
int sqlite3_T_double(sqlite3_context* aCtx, double aValue) {
::sqlite3_result_double(aCtx, aValue);
return SQLITE_OK;
}
int sqlite3_T_text(sqlite3_context* aCtx, const nsCString& aValue) {
::sqlite3_result_text(aCtx, aValue.get(), aValue.Length(), SQLITE_TRANSIENT);
return SQLITE_OK;
}
int sqlite3_T_text16(sqlite3_context* aCtx, const nsString& aValue) {
::sqlite3_result_text16(
aCtx, aValue.get(),
aValue.Length() * sizeof(char16_t), // Number of bytes.
SQLITE_TRANSIENT);
return SQLITE_OK;
}
int sqlite3_T_null(sqlite3_context* aCtx) {
::sqlite3_result_null(aCtx);
return SQLITE_OK;
}
int sqlite3_T_blob(sqlite3_context* aCtx, const void* aData, int aSize) {
::sqlite3_result_blob(aCtx, aData, aSize, free);
return SQLITE_OK;
}
#include "variantToSQLiteT_impl.h"
////////////////////////////////////////////////////////////////////////////////
//// Modules
struct Module {
const char* name;
int (*registerFunc)(sqlite3*, const char*);
};
Module gModules[] = {{"filesystem", RegisterFileSystemModule}};
////////////////////////////////////////////////////////////////////////////////
//// Local Functions
int tracefunc(unsigned aReason, void* aClosure, void* aP, void* aX) {
switch (aReason) {
case SQLITE_TRACE_STMT: {
// aP is a pointer to the prepared statement.
sqlite3_stmt* stmt = static_cast<sqlite3_stmt*>(aP);
// aX is a pointer to a string containing the unexpanded SQL or a comment,
// starting with "--"" in case of a trigger.
char* expanded = static_cast<char*>(aX);
// Simulate what sqlite_trace was doing.
if (!::strncmp(expanded, "--", 2)) {
MOZ_LOG(gStorageLog, LogLevel::Debug,
("TRACE_STMT on %p: '%s'", aClosure, expanded));
} else {
char* sql = ::sqlite3_expanded_sql(stmt);
MOZ_LOG(gStorageLog, LogLevel::Debug,
("TRACE_STMT on %p: '%s'", aClosure, sql));
::sqlite3_free(sql);
}
break;
}
case SQLITE_TRACE_PROFILE: {
// aX is pointer to a 64bit integer containing nanoseconds it took to
// execute the last command.
sqlite_int64 time = *(static_cast<sqlite_int64*>(aX)) / 1000000;
if (time > 0) {
MOZ_LOG(gStorageLog, LogLevel::Debug,
("TRACE_TIME on %p: %lldms", aClosure, time));
}
break;
}
}
return 0;
}
void basicFunctionHelper(sqlite3_context* aCtx, int aArgc,
sqlite3_value** aArgv) {
void* userData = ::sqlite3_user_data(aCtx);
mozIStorageFunction* func = static_cast<mozIStorageFunction*>(userData);
RefPtr<ArgValueArray> arguments(new ArgValueArray(aArgc, aArgv));
if (!arguments) return;
nsCOMPtr<nsIVariant> result;
nsresult rv = func->OnFunctionCall(arguments, getter_AddRefs(result));
if (NS_FAILED(rv)) {
nsAutoCString errorMessage;
GetErrorName(rv, errorMessage);
errorMessage.InsertLiteral("User function returned ", 0);
errorMessage.Append('!');
NS_WARNING(errorMessage.get());
::sqlite3_result_error(aCtx, errorMessage.get(), -1);
::sqlite3_result_error_code(aCtx, nsresultToSQLiteResult(rv));
return;
}
int retcode = variantToSQLiteT(aCtx, result);
if (retcode != SQLITE_OK) {
NS_WARNING("User function returned invalid data type!");
::sqlite3_result_error(aCtx, "User function returned invalid data type",
-1);
}
}
/**
* This code is heavily based on the sample at:
*/
class UnlockNotification {
public:
UnlockNotification()
: mMutex("UnlockNotification mMutex"),
mCondVar(mMutex, "UnlockNotification condVar"),
mSignaled(false) {}
void Wait() {
MutexAutoLock lock(mMutex);
while (!mSignaled) {
(void)mCondVar.Wait();
}
}
void Signal() {
MutexAutoLock lock(mMutex);
mSignaled = true;
(void)mCondVar.Notify();
}
private:
Mutex mMutex;
CondVar mCondVar;
bool mSignaled;
};
void UnlockNotifyCallback(void** aArgs, int aArgsSize) {
for (int i = 0; i < aArgsSize; i++) {
UnlockNotification* notification =
static_cast<UnlockNotification*>(aArgs[i]);
notification->Signal();
}
}
int WaitForUnlockNotify(sqlite3* aDatabase) {
UnlockNotification notification;
int srv =
::sqlite3_unlock_notify(aDatabase, UnlockNotifyCallback, &notification);
MOZ_ASSERT(srv == SQLITE_LOCKED || srv == SQLITE_OK);
if (srv == SQLITE_OK) {
notification.Wait();
}
return srv;
}
////////////////////////////////////////////////////////////////////////////////
//// Local Classes
class AsyncCloseConnection final : public Runnable {
public:
AsyncCloseConnection(Connection* aConnection, sqlite3* aNativeConnection,
nsIRunnable* aCallbackEvent)
: Runnable("storage::AsyncCloseConnection"),
mConnection(aConnection),
mNativeConnection(aNativeConnection),
mCallbackEvent(aCallbackEvent) {}
NS_IMETHOD Run() override {
// This code is executed on the background thread
MOZ_ASSERT(NS_GetCurrentThread() != mConnection->threadOpenedOn);
nsCOMPtr<nsIRunnable> event =
NewRunnableMethod("storage::Connection::shutdownAsyncThread",
mConnection, &Connection::shutdownAsyncThread);
MOZ_ALWAYS_SUCCEEDS(NS_DispatchToMainThread(event));
// Internal close.
(void)mConnection->internalClose(mNativeConnection);
// Callback
if (mCallbackEvent) {
nsCOMPtr<nsIThread> thread;
(void)NS_GetMainThread(getter_AddRefs(thread));
(void)thread->Dispatch(mCallbackEvent, NS_DISPATCH_NORMAL);
}
return NS_OK;
}
~AsyncCloseConnection() override {
NS_ReleaseOnMainThread("AsyncCloseConnection::mConnection",
mConnection.forget());
NS_ReleaseOnMainThread("AsyncCloseConnection::mCallbackEvent",
mCallbackEvent.forget());
}
private:
RefPtr<Connection> mConnection;
sqlite3* mNativeConnection;
nsCOMPtr<nsIRunnable> mCallbackEvent;
};
/**
* An event used to initialize the clone of a connection.
*
* Must be executed on the clone's async execution thread.
*/
class AsyncInitializeClone final : public Runnable {
public:
/**
* @param aConnection The connection being cloned.
* @param aClone The clone.
* @param aReadOnly If |true|, the clone is read only.
* @param aCallback A callback to trigger once initialization
* is complete. This event will be called on
* aClone->threadOpenedOn.
*/
AsyncInitializeClone(Connection* aConnection, Connection* aClone,
const bool aReadOnly,
mozIStorageCompletionCallback* aCallback)
: Runnable("storage::AsyncInitializeClone"),
mConnection(aConnection),
mClone(aClone),
mReadOnly(aReadOnly),
mCallback(aCallback) {
MOZ_ASSERT(NS_IsMainThread());
}
NS_IMETHOD Run() override {
MOZ_ASSERT(!NS_IsMainThread());
nsresult rv = mConnection->initializeClone(mClone, mReadOnly);
if (NS_FAILED(rv)) {
return Dispatch(rv, nullptr);
}
return Dispatch(NS_OK,
NS_ISUPPORTS_CAST(mozIStorageAsyncConnection*, mClone));
}
private:
nsresult Dispatch(nsresult aResult, nsISupports* aValue) {
RefPtr<CallbackComplete> event =
new CallbackComplete(aResult, aValue, mCallback.forget());
return mClone->threadOpenedOn->Dispatch(event, NS_DISPATCH_NORMAL);
}
~AsyncInitializeClone() override {
nsCOMPtr<nsIThread> thread;
DebugOnly<nsresult> rv = NS_GetMainThread(getter_AddRefs(thread));
MOZ_ASSERT(NS_SUCCEEDED(rv));
// Handle ambiguous nsISupports inheritance.
NS_ProxyRelease("AsyncInitializeClone::mConnection", thread,
mConnection.forget());
NS_ProxyRelease("AsyncInitializeClone::mClone", thread, mClone.forget());
// Generally, the callback will be released by CallbackComplete.
// However, if for some reason Run() is not executed, we still
// need to ensure that it is released here.
NS_ProxyRelease("AsyncInitializeClone::mCallback", thread,
mCallback.forget());
}
RefPtr<Connection> mConnection;
RefPtr<Connection> mClone;
const bool mReadOnly;
nsCOMPtr<mozIStorageCompletionCallback> mCallback;
};
/**
* A listener for async connection closing.
*/
class CloseListener final : public mozIStorageCompletionCallback {
public:
NS_DECL_ISUPPORTS
CloseListener() : mClosed(false) {}
NS_IMETHOD Complete(nsresult, nsISupports*) override {
mClosed = true;
return NS_OK;
}
bool mClosed;
private:
~CloseListener() = default;
};
NS_IMPL_ISUPPORTS(CloseListener, mozIStorageCompletionCallback)
} // namespace
////////////////////////////////////////////////////////////////////////////////
//// Connection
Connection::Connection(Service* aService, int aFlags,
ConnectionOperation aSupportedOperations,
bool aIgnoreLockingMode)
: sharedAsyncExecutionMutex("Connection::sharedAsyncExecutionMutex"),
sharedDBMutex("Connection::sharedDBMutex"),
threadOpenedOn(do_GetCurrentThread()),
mDBConn(nullptr),
mAsyncExecutionThreadShuttingDown(false),
mConnectionClosed(false),
mDefaultTransactionType(mozIStorageConnection::TRANSACTION_DEFERRED),
mDestroying(false),
mProgressHandler(nullptr),
mFlags(aFlags),
mIgnoreLockingMode(aIgnoreLockingMode),
mStorageService(aService),
mSupportedOperations(aSupportedOperations),
mTransactionNestingLevel(0) {
MOZ_ASSERT(!mIgnoreLockingMode || mFlags & SQLITE_OPEN_READONLY,
"Can't ignore locking for a non-readonly connection!");
mStorageService->registerConnection(this);
}
Connection::~Connection() {
// Failsafe Close() occurs in our custom Release method because of
// complications related to Close() potentially invoking AsyncClose() which
// will increment our refcount.
MOZ_ASSERT(!mAsyncExecutionThread,
"The async thread has not been shutdown properly!");
}
NS_IMPL_ADDREF(Connection)
NS_INTERFACE_MAP_BEGIN(Connection)
NS_INTERFACE_MAP_ENTRY(mozIStorageAsyncConnection)
NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
NS_INTERFACE_MAP_ENTRY(mozIStorageConnection)
NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, mozIStorageConnection)
NS_INTERFACE_MAP_END
// This is identical to what NS_IMPL_RELEASE provides, but with the
// extra |1 == count| case.
NS_IMETHODIMP_(MozExternalRefCountType) Connection::Release(void) {
MOZ_ASSERT(0 != mRefCnt, "dup release");
nsrefcnt count = --mRefCnt;
NS_LOG_RELEASE(this, count, "Connection");
if (1 == count) {
// If the refcount went to 1, the single reference must be from
// gService->mConnections (in class |Service|). And the code calling
// Release is either:
// - The "user" code that had created the connection, releasing on any
// thread.
// - One of Service's getConnections() callers had acquired a strong
// reference to the Connection that out-lived the last "user" reference,
// and now that just got dropped. Note that this reference could be
// getting dropped on the main thread or Connection->threadOpenedOn
// (because of the NewRunnableMethod used by minimizeMemory).
//
// Either way, we should now perform our failsafe Close() and unregister.
// However, we only want to do this once, and the reality is that our
// refcount could go back up above 1 and down again at any time if we are
// off the main thread and getConnections() gets called on the main thread,
// so we use an atomic here to do this exactly once.
if (mDestroying.compareExchange(false, true)) {
// Close the connection, dispatching to the opening thread if we're not
// on that thread already and that thread is still accepting runnables.
// We do this because it's possible we're on the main thread because of
// getConnections(), and we REALLY don't want to transfer I/O to the main
// thread if we can avoid it.
if (threadOpenedOn->IsOnCurrentThread()) {
// This could cause SpinningSynchronousClose() to be invoked and AddRef
// triggered for AsyncCloseConnection's strong ref if the conn was ever
// use for async purposes. (Main-thread only, though.)
Unused << synchronousClose();
} else {
nsCOMPtr<nsIRunnable> event =
NewRunnableMethod("storage::Connection::synchronousClose", this,
&Connection::synchronousClose);
if (NS_FAILED(
threadOpenedOn->Dispatch(event.forget(), NS_DISPATCH_NORMAL))) {
// The target thread was dead and so we've just leaked our runnable.
// This should not happen because our non-main-thread consumers should
// be explicitly closing their connections, not relying on us to close
// them for them. (It's okay to let a statement go out of scope for
// automatic cleanup, but not a Connection.)
MOZ_ASSERT(false,
"Leaked Connection::synchronousClose(), ownership fail.");
Unused << synchronousClose();
}
}
// This will drop its strong reference right here, right now.
mStorageService->unregisterConnection(this);
}
} else if (0 == count) {
mRefCnt = 1; /* stabilize */
#if 0 /* enable this to find non-threadsafe destructors: */
NS_ASSERT_OWNINGTHREAD(Connection);
#endif
delete (this);
return 0;
}
return count;
}
int32_t Connection::getSqliteRuntimeStatus(int32_t aStatusOption,
int32_t* aMaxValue) {
MOZ_ASSERT(connectionReady(), "A connection must exist at this point");
int curr = 0, max = 0;
DebugOnly<int> rc =
::sqlite3_db_status(mDBConn, aStatusOption, &curr, &max, 0);
MOZ_ASSERT(NS_SUCCEEDED(convertResultCode(rc)));
if (aMaxValue) *aMaxValue = max;
return curr;
}
nsIEventTarget* Connection::getAsyncExecutionTarget() {
NS_ENSURE_TRUE(threadOpenedOn == NS_GetCurrentThread(), nullptr);
// Don't return the asynchronous thread if we are shutting down.
if (mAsyncExecutionThreadShuttingDown) {
return nullptr;
}
// Create the async thread if there's none yet.
if (!mAsyncExecutionThread) {
static nsThreadPoolNaming naming;
nsresult rv = NS_NewNamedThread(naming.GetNextThreadName("mozStorage"),
getter_AddRefs(mAsyncExecutionThread));
if (NS_FAILED(rv)) {
NS_WARNING("Failed to create async thread.");
return nullptr;
}
mAsyncExecutionThread->SetNameForWakeupTelemetry("mozStorage (all)"_ns);
}
return mAsyncExecutionThread;
}
void Connection::RecordOpenStatus(nsresult rv) {
nsCString histogramKey = mTelemetryFilename;
if (histogramKey.IsEmpty()) {
histogramKey.AssignLiteral("unknown");
}
if (NS_SUCCEEDED(rv)) {
AccumulateCategoricalKeyed(histogramKey, LABELS_SQLITE_STORE_OPEN::success);
return;
}
switch (rv) {
case NS_ERROR_FILE_CORRUPTED:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_OPEN::corrupt);
break;
case NS_ERROR_STORAGE_IOERR:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_OPEN::diskio);
break;
case NS_ERROR_FILE_ACCESS_DENIED:
case NS_ERROR_FILE_IS_LOCKED:
case NS_ERROR_FILE_READ_ONLY:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_OPEN::access);
break;
case NS_ERROR_FILE_NO_DEVICE_SPACE:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_OPEN::diskspace);
break;
default:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_OPEN::failure);
}
}
void Connection::RecordQueryStatus(int srv) {
nsCString histogramKey = mTelemetryFilename;
if (histogramKey.IsEmpty()) {
histogramKey.AssignLiteral("unknown");
}
switch (srv) {
case SQLITE_OK:
case SQLITE_ROW:
case SQLITE_DONE:
// Note that these are returned when we intentionally cancel a statement so
// they aren't indicating a failure.
case SQLITE_ABORT:
case SQLITE_INTERRUPT:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_QUERY::success);
break;
case SQLITE_CORRUPT:
case SQLITE_NOTADB:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_QUERY::corrupt);
break;
case SQLITE_PERM:
case SQLITE_CANTOPEN:
case SQLITE_LOCKED:
case SQLITE_READONLY:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_QUERY::access);
break;
case SQLITE_IOERR:
case SQLITE_NOLFS:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_QUERY::diskio);
break;
case SQLITE_FULL:
case SQLITE_TOOBIG:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_OPEN::diskspace);
break;
case SQLITE_CONSTRAINT:
case SQLITE_RANGE:
case SQLITE_MISMATCH:
case SQLITE_MISUSE:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_OPEN::misuse);
break;
case SQLITE_BUSY:
AccumulateCategoricalKeyed(histogramKey, LABELS_SQLITE_STORE_OPEN::busy);
break;
default:
AccumulateCategoricalKeyed(histogramKey,
LABELS_SQLITE_STORE_QUERY::failure);
}
}
nsresult Connection::initialize(const nsACString& aStorageKey,
const nsACString& aName) {
MOZ_ASSERT(aStorageKey.Equals(kMozStorageMemoryStorageKey));
NS_ASSERTION(!connectionReady(),
"Initialize called on already opened database!");
MOZ_ASSERT(!mIgnoreLockingMode, "Can't ignore locking on an in-memory db.");
AUTO_PROFILER_LABEL("Connection::initialize", OTHER);
mStorageKey = aStorageKey;
mName = aName;
// in memory database requested, sqlite uses a magic file name
const nsAutoCString path =
mName.IsEmpty() ? nsAutoCString(":memory:"_ns)
: "file:"_ns + mName + "?mode=memory&cache=shared"_ns;
mTelemetryFilename.AssignLiteral(":memory:");
int srv = ::sqlite3_open_v2(path.get(), &mDBConn, mFlags,
GetTelemetryVFSName(true));
if (srv != SQLITE_OK) {
mDBConn = nullptr;
nsresult rv = convertResultCode(srv);
RecordOpenStatus(rv);
return rv;
}
#ifdef MOZ_SQLITE_FTS3_TOKENIZER
srv =
::sqlite3_db_config(mDBConn, SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
MOZ_ASSERT(srv == SQLITE_OK,
"SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER should be enabled");
#endif
// Do not set mDatabaseFile or mFileURL here since this is a "memory"
// database.
nsresult rv = initializeInternal();
RecordOpenStatus(rv);
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
nsresult Connection::initialize(nsIFile* aDatabaseFile) {
NS_ASSERTION(aDatabaseFile, "Passed null file!");
NS_ASSERTION(!connectionReady(),
"Initialize called on already opened database!");
AUTO_PROFILER_LABEL("Connection::initialize", OTHER);
// Do not set mFileURL here since this is database does not have an associated
// URL.
mDatabaseFile = aDatabaseFile;
aDatabaseFile->GetNativeLeafName(mTelemetryFilename);
nsAutoString path;
nsresult rv = aDatabaseFile->GetPath(path);
NS_ENSURE_SUCCESS(rv, rv);
#ifdef XP_WIN
static const char* sIgnoreLockingVFS = "win32-none";
#else
static const char* sIgnoreLockingVFS = "unix-none";
#endif
bool exclusive = StaticPrefs::storage_sqlite_exclusiveLock_enabled();
int srv;
if (mIgnoreLockingMode) {
exclusive = false;
srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn, mFlags,
sIgnoreLockingVFS);
} else {
srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn, mFlags,
GetTelemetryVFSName(exclusive));
if (exclusive && (srv == SQLITE_LOCKED || srv == SQLITE_BUSY)) {
// Retry without trying to get an exclusive lock.
exclusive = false;
srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn,
mFlags, GetTelemetryVFSName(false));
}
}
if (srv != SQLITE_OK) {
mDBConn = nullptr;
rv = convertResultCode(srv);
RecordOpenStatus(rv);
return rv;
}
rv = initializeInternal();
if (exclusive &&
(rv == NS_ERROR_STORAGE_BUSY || rv == NS_ERROR_FILE_IS_LOCKED)) {
// Usually SQLite will fail to acquire an exclusive lock on opening, but in
// some cases it may successfully open the database and then lock on the
// first query execution. When initializeInternal fails it closes the
// connection, so we can try to restart it in non-exclusive mode.
srv = ::sqlite3_open_v2(NS_ConvertUTF16toUTF8(path).get(), &mDBConn, mFlags,
GetTelemetryVFSName(false));
if (srv == SQLITE_OK) {
rv = initializeInternal();
}
}
RecordOpenStatus(rv);
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
nsresult Connection::initialize(nsIFileURL* aFileURL,
const nsACString& aTelemetryFilename) {
NS_ASSERTION(aFileURL, "Passed null file URL!");
NS_ASSERTION(!connectionReady(),
"Initialize called on already opened database!");
AUTO_PROFILER_LABEL("Connection::initialize", OTHER);
nsCOMPtr<nsIFile> databaseFile;
nsresult rv = aFileURL->GetFile(getter_AddRefs(databaseFile));
NS_ENSURE_SUCCESS(rv, rv);
// Set both mDatabaseFile and mFileURL here.
mFileURL = aFileURL;
mDatabaseFile = databaseFile;
if (!aTelemetryFilename.IsEmpty()) {
mTelemetryFilename = aTelemetryFilename;
} else {
databaseFile->GetNativeLeafName(mTelemetryFilename);
}
nsAutoCString spec;
rv = aFileURL->GetSpec(spec);
NS_ENSURE_SUCCESS(rv, rv);
bool exclusive = StaticPrefs::storage_sqlite_exclusiveLock_enabled();
// If there is a key specified, we need to use the obfuscating VFS.
nsAutoCString query;
rv = aFileURL->GetQuery(query);
NS_ENSURE_SUCCESS(rv, rv);
const char* const vfs =
URLParams::Parse(query,
[](const nsAString& aName, const nsAString& aValue) {
return aName.EqualsLiteral("key");
})
? GetObfuscatingVFSName()
: GetTelemetryVFSName(exclusive);
int srv = ::sqlite3_open_v2(spec.get(), &mDBConn, mFlags, vfs);
if (srv != SQLITE_OK) {
mDBConn = nullptr;
rv = convertResultCode(srv);
RecordOpenStatus(rv);
return rv;
}
rv = initializeInternal();
RecordOpenStatus(rv);
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
nsresult Connection::initializeInternal() {
MOZ_ASSERT(mDBConn);
auto guard = MakeScopeExit([&]() { initializeFailed(); });
mConnectionClosed = false;
#ifdef MOZ_SQLITE_FTS3_TOKENIZER
DebugOnly<int> srv2 =
::sqlite3_db_config(mDBConn, SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
MOZ_ASSERT(srv2 == SQLITE_OK,
"SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER should be enabled");
#endif
MOZ_ASSERT(!mTelemetryFilename.IsEmpty(),
"A telemetry filename should have been set by now.");
// Properly wrap the database handle's mutex.
sharedDBMutex.initWithMutex(sqlite3_db_mutex(mDBConn));
// SQLite tracing can slow down queries (especially long queries)
// significantly. Don't trace unless the user is actively monitoring SQLite.
if (MOZ_LOG_TEST(gStorageLog, LogLevel::Debug)) {
::sqlite3_trace_v2(mDBConn, SQLITE_TRACE_STMT | SQLITE_TRACE_PROFILE,
tracefunc, this);
MOZ_LOG(
gStorageLog, LogLevel::Debug,
("Opening connection to '%s' (%p)", mTelemetryFilename.get(), this));
}
int64_t pageSize = Service::kDefaultPageSize;
// Set page_size to the preferred default value. This is effective only if
// the database has just been created, otherwise, if the database does not
// use WAL journal mode, a VACUUM operation will updated its page_size.
nsAutoCString pageSizeQuery(MOZ_STORAGE_UNIQUIFY_QUERY_STR
"PRAGMA page_size = ");
pageSizeQuery.AppendInt(pageSize);
int srv = executeSql(mDBConn, pageSizeQuery.get());
if (srv != SQLITE_OK) {
return convertResultCode(srv);
}
// Setting the cache_size forces the database open, verifying if it is valid
// or corrupt. So this is executed regardless it being actually needed.
// The cache_size is calculated from the actual page_size, to save memory.
nsAutoCString cacheSizeQuery(MOZ_STORAGE_UNIQUIFY_QUERY_STR
"PRAGMA cache_size = ");
cacheSizeQuery.AppendInt(-MAX_CACHE_SIZE_KIBIBYTES);
srv = executeSql(mDBConn, cacheSizeQuery.get());
if (srv != SQLITE_OK) {
return convertResultCode(srv);
}
// Register our built-in SQL functions.
srv = registerFunctions(mDBConn);
if (srv != SQLITE_OK) {
return convertResultCode(srv);
}
// Register our built-in SQL collating sequences.
srv = registerCollations(mDBConn, mStorageService);
if (srv != SQLITE_OK) {
return convertResultCode(srv);
}
// Set the default synchronous value. Each consumer can switch this
// accordingly to their needs.
#if defined(ANDROID)
// Android prefers synchronous = OFF for performance reasons.
Unused << ExecuteSimpleSQL("PRAGMA synchronous = OFF;"_ns);
#else
// Normal is the suggested value for WAL journals.
Unused << ExecuteSimpleSQL("PRAGMA synchronous = NORMAL;"_ns);
#endif
// Initialization succeeded, we can stop guarding for failures.
guard.release();
return NS_OK;
}
nsresult Connection::initializeOnAsyncThread(nsIFile* aStorageFile) {
MOZ_ASSERT(threadOpenedOn != NS_GetCurrentThread());
nsresult rv = aStorageFile
? initialize(aStorageFile)
: initialize(kMozStorageMemoryStorageKey, VoidCString());
if (NS_FAILED(rv)) {
// Shutdown the async thread, since initialization failed.
MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
mAsyncExecutionThreadShuttingDown = true;
nsCOMPtr<nsIRunnable> event =
NewRunnableMethod("Connection::shutdownAsyncThread", this,
&Connection::shutdownAsyncThread);
Unused << NS_DispatchToMainThread(event);
}
return rv;
}
void Connection::initializeFailed() {
{
MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
mConnectionClosed = true;
}
MOZ_ALWAYS_TRUE(::sqlite3_close(mDBConn) == SQLITE_OK);
mDBConn = nullptr;
sharedDBMutex.destroy();
}
nsresult Connection::databaseElementExists(
enum DatabaseElementType aElementType, const nsACString& aElementName,
bool* _exists) {
if (!connectionReady()) {
return NS_ERROR_NOT_AVAILABLE;
}
nsresult rv = ensureOperationSupported(SYNCHRONOUS);
if (NS_FAILED(rv)) {
return rv;
}
// When constructing the query, make sure to SELECT the correct db's
// sqlite_master if the user is prefixing the element with a specific db. ex:
// sample.test
nsCString query("SELECT name FROM (SELECT * FROM ");
nsDependentCSubstring element;
int32_t ind = aElementName.FindChar('.');
if (ind == kNotFound) {
element.Assign(aElementName);
} else {
nsDependentCSubstring db(Substring(aElementName, 0, ind + 1));
element.Assign(Substring(aElementName, ind + 1, aElementName.Length()));
query.Append(db);
}
query.AppendLiteral(
"sqlite_master UNION ALL SELECT * FROM sqlite_temp_master) WHERE type = "
"'");
switch (aElementType) {
case INDEX:
query.AppendLiteral("index");
break;
case TABLE:
query.AppendLiteral("table");
break;
}
query.AppendLiteral("' AND name ='");
query.Append(element);
query.Append('\'');
sqlite3_stmt* stmt;
int srv = prepareStatement(mDBConn, query, &stmt);
if (srv != SQLITE_OK) {
RecordQueryStatus(srv);
return convertResultCode(srv);
}
srv = stepStatement(mDBConn, stmt);
// we just care about the return value from step
(void)::sqlite3_finalize(stmt);
RecordQueryStatus(srv);
if (srv == SQLITE_ROW) {
*_exists = true;
return NS_OK;
}
if (srv == SQLITE_DONE) {
*_exists = false;
return NS_OK;
}
return convertResultCode(srv);
}
bool Connection::findFunctionByInstance(mozIStorageFunction* aInstance) {
sharedDBMutex.assertCurrentThreadOwns();
for (const auto& data : mFunctions.Values()) {
if (data.function == aInstance) {
return true;
}
}
return false;
}
/* static */
int Connection::sProgressHelper(void* aArg) {
Connection* _this = static_cast<Connection*>(aArg);
return _this->progressHandler();
}
int Connection::progressHandler() {
sharedDBMutex.assertCurrentThreadOwns();
if (mProgressHandler) {
bool result;
nsresult rv = mProgressHandler->OnProgress(this, &result);
if (NS_FAILED(rv)) return 0; // Don't break request
return result ? 1 : 0;
}
return 0;
}
nsresult Connection::setClosedState() {
// Ensure that we are on the correct thread to close the database.
bool onOpenedThread;
nsresult rv = threadOpenedOn->IsOnCurrentThread(&onOpenedThread);
NS_ENSURE_SUCCESS(rv, rv);
if (!onOpenedThread) {
NS_ERROR("Must close the database on the thread that you opened it with!");
return NS_ERROR_UNEXPECTED;
}
// Flag that we are shutting down the async thread, so that
// getAsyncExecutionTarget knows not to expose/create the async thread.
{
MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
NS_ENSURE_FALSE(mAsyncExecutionThreadShuttingDown, NS_ERROR_UNEXPECTED);
mAsyncExecutionThreadShuttingDown = true;
// Set the property to null before closing the connection, otherwise the
// other functions in the module may try to use the connection after it is
// closed.
mDBConn = nullptr;
}
return NS_OK;
}
bool Connection::operationSupported(ConnectionOperation aOperationType) {
if (aOperationType == ASYNCHRONOUS) {
// Async operations are supported for all connections, on any thread.
return true;
}
// Sync operations are supported for sync connections (on any thread), and
// async connections on a background thread.
MOZ_ASSERT(aOperationType == SYNCHRONOUS);
return mSupportedOperations == SYNCHRONOUS || !NS_IsMainThread();
}
nsresult Connection::ensureOperationSupported(
ConnectionOperation aOperationType) {
if (NS_WARN_IF(!operationSupported(aOperationType))) {
#ifdef DEBUG
if (NS_IsMainThread()) {
nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
Unused << xpc->DebugDumpJSStack(false, false, false);
}
#endif
MOZ_ASSERT(false,
"Don't use async connections synchronously on the main thread");
return NS_ERROR_NOT_AVAILABLE;
}
return NS_OK;
}
bool Connection::isConnectionReadyOnThisThread() {
MOZ_ASSERT_IF(connectionReady(), !mConnectionClosed);
if (mAsyncExecutionThread && mAsyncExecutionThread->IsOnCurrentThread()) {
return true;
}
return connectionReady();
}
bool Connection::isClosing() {
MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
return mAsyncExecutionThreadShuttingDown && !mConnectionClosed;
}
bool Connection::isClosed() {
MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
return mConnectionClosed;
}
bool Connection::isClosed(MutexAutoLock& lock) { return mConnectionClosed; }
bool Connection::isAsyncExecutionThreadAvailable() {
MOZ_ASSERT(threadOpenedOn == NS_GetCurrentThread());
return mAsyncExecutionThread && !mAsyncExecutionThreadShuttingDown;
}
void Connection::shutdownAsyncThread() {
MOZ_ASSERT(threadOpenedOn == NS_GetCurrentThread());
MOZ_ASSERT(mAsyncExecutionThread);
MOZ_ASSERT(mAsyncExecutionThreadShuttingDown);
MOZ_ALWAYS_SUCCEEDS(mAsyncExecutionThread->Shutdown());
mAsyncExecutionThread = nullptr;
}
nsresult Connection::internalClose(sqlite3* aNativeConnection) {
#ifdef DEBUG
{ // Make sure we have marked our async thread as shutting down.
MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
MOZ_ASSERT(mAsyncExecutionThreadShuttingDown,
"Did not call setClosedState!");
MOZ_ASSERT(!isClosed(lockedScope), "Unexpected closed state");
}
#endif // DEBUG
if (MOZ_LOG_TEST(gStorageLog, LogLevel::Debug)) {
nsAutoCString leafName(":memory");
if (mDatabaseFile) (void)mDatabaseFile->GetNativeLeafName(leafName);
MOZ_LOG(gStorageLog, LogLevel::Debug,
("Closing connection to '%s'", leafName.get()));
}
// At this stage, we may still have statements that need to be
// finalized. Attempt to close the database connection. This will
// always disconnect any virtual tables and cleanly finalize their
// internal statements. Once this is done, closing may fail due to
// unfinalized client statements, in which case we need to finalize
// these statements and close again.
{
MutexAutoLock lockedScope(sharedAsyncExecutionMutex);
mConnectionClosed = true;
}
// Nothing else needs to be done if we don't have a connection here.
if (!aNativeConnection) return NS_OK;
int srv = ::sqlite3_close(aNativeConnection);
if (srv == SQLITE_BUSY) {
{
// Nothing else should change the connection or statements status until we
// are done here.
SQLiteMutexAutoLock lockedScope(sharedDBMutex);
// We still have non-finalized statements. Finalize them.
sqlite3_stmt* stmt = nullptr;
while ((stmt = ::sqlite3_next_stmt(aNativeConnection, stmt))) {
MOZ_LOG(gStorageLog, LogLevel::Debug,
("Auto-finalizing SQL statement '%s' (%p)", ::sqlite3_sql(stmt),
stmt));
#ifdef DEBUG
SmprintfPointer msg = ::mozilla::Smprintf(
"SQL statement '%s' (%p) should have been finalized before closing "
"the connection",
::sqlite3_sql(stmt), stmt);
NS_WARNING(msg.get());
#endif // DEBUG
srv = ::sqlite3_finalize(stmt);
#ifdef DEBUG
if (srv != SQLITE_OK) {
SmprintfPointer msg = ::mozilla::Smprintf(
"Could not finalize SQL statement (%p)", stmt);
NS_WARNING(msg.get());
}
#endif // DEBUG
// Ensure that the loop continues properly, whether closing has
// succeeded or not.
if (srv == SQLITE_OK) {
stmt = nullptr;
}
}
// Scope exiting will unlock the mutex before we invoke sqlite3_close()
// again, since Sqlite will try to acquire it.
}
// Now that all statements have been finalized, we
// should be able to close.
srv = ::sqlite3_close(aNativeConnection);
MOZ_ASSERT(false,
"Had to forcibly close the database connection because not all "
"the statements have been finalized.");
}
if (srv == SQLITE_OK) {
sharedDBMutex.destroy();
} else {
MOZ_ASSERT(false,
"sqlite3_close failed. There are probably outstanding "
"statements that are listed above!");
}
return convertResultCode(srv);
}
nsCString Connection::getFilename() { return mTelemetryFilename; }
int Connection::stepStatement(sqlite3* aNativeConnection,
sqlite3_stmt* aStatement) {
MOZ_ASSERT(aStatement);
AUTO_PROFILER_LABEL_DYNAMIC_CSTR("Connection::stepStatement", OTHER,
::sqlite3_sql(aStatement));
bool checkedMainThread = false;
TimeStamp startTime = TimeStamp::Now();
// The connection may have been closed if the executing statement has been
// created and cached after a call to asyncClose() but before the actual
// sqlite3_close(). This usually happens when other tasks using cached
// statements are asynchronously scheduled for execution and any of them ends
// up after asyncClose. See bug 728653 for details.
if (!isConnectionReadyOnThisThread()) return SQLITE_MISUSE;
(void)::sqlite3_extended_result_codes(aNativeConnection, 1);
int srv;
while ((srv = ::sqlite3_step(aStatement)) == SQLITE_LOCKED_SHAREDCACHE) {
if (!checkedMainThread) {
checkedMainThread = true;
if (::NS_IsMainThread()) {
NS_WARNING("We won't allow blocking on the main thread!");
break;
}
}
srv = WaitForUnlockNotify(aNativeConnection);
if (srv != SQLITE_OK) {
break;
}
::sqlite3_reset(aStatement);
}
// Report very slow SQL statements to Telemetry
TimeDuration duration = TimeStamp::Now() - startTime;
const uint32_t threshold = NS_IsMainThread()
? Telemetry::kSlowSQLThresholdForMainThread
: Telemetry::kSlowSQLThresholdForHelperThreads;
if (duration.ToMilliseconds() >= threshold) {
nsDependentCString statementString(::sqlite3_sql(aStatement));
Telemetry::RecordSlowSQLStatement(statementString, mTelemetryFilename,
duration.ToMilliseconds());
}
(void)::sqlite3_extended_result_codes(aNativeConnection, 0);
// Drop off the extended result bits of the result code.
return srv & 0xFF;
}
int Connection::prepareStatement(sqlite3* aNativeConnection,
const nsCString& aSQL, sqlite3_stmt** _stmt) {
// We should not even try to prepare statements after the connection has
// been closed.
if (!isConnectionReadyOnThisThread()) return SQLITE_MISUSE;
bool checkedMainThread = false;
(void)::sqlite3_extended_result_codes(aNativeConnection, 1);
int srv;
while ((srv = ::sqlite3_prepare_v2(aNativeConnection, aSQL.get(), -1, _stmt,
nullptr)) == SQLITE_LOCKED_SHAREDCACHE) {
if (!checkedMainThread) {
checkedMainThread = true;
if (::NS_IsMainThread()) {
NS_WARNING("We won't allow blocking on the main thread!");
break;
}
}
srv = WaitForUnlockNotify(aNativeConnection);
if (srv != SQLITE_OK) {
break;
}
}
if (srv != SQLITE_OK) {
nsCString warnMsg;
warnMsg.AppendLiteral("The SQL statement '");
warnMsg.Append(aSQL);
warnMsg.AppendLiteral("' could not be compiled due to an error: ");
warnMsg.Append(::sqlite3_errmsg(aNativeConnection));
#ifdef DEBUG
NS_WARNING(warnMsg.get());
#endif
MOZ_LOG(gStorageLog, LogLevel::Error, ("%s", warnMsg.get()));
}
(void)::sqlite3_extended_result_codes(aNativeConnection, 0);
// Drop off the extended result bits of the result code.
int rc = srv & 0xFF;
// sqlite will return OK on a comment only string and set _stmt to nullptr.
// The callers of this function are used to only checking the return value,
// so it is safer to return an error code.
if (rc == SQLITE_OK && *_stmt == nullptr) {
return SQLITE_MISUSE;
}
return rc;
}
int Connection::executeSql(sqlite3* aNativeConnection, const char* aSqlString) {
if (!isConnectionReadyOnThisThread()) return SQLITE_MISUSE;
AUTO_PROFILER_LABEL_DYNAMIC_CSTR("Connection::executeSql", OTHER, aSqlString);
TimeStamp startTime = TimeStamp::Now();
int srv =
::sqlite3_exec(aNativeConnection, aSqlString, nullptr, nullptr, nullptr);
RecordQueryStatus(srv);
// Report very slow SQL statements to Telemetry
TimeDuration duration = TimeStamp::Now() - startTime;
const uint32_t threshold = NS_IsMainThread()
? Telemetry::kSlowSQLThresholdForMainThread
: Telemetry::kSlowSQLThresholdForHelperThreads;
if (duration.ToMilliseconds() >= threshold) {
nsDependentCString statementString(aSqlString);
Telemetry::RecordSlowSQLStatement(statementString, mTelemetryFilename,
duration.ToMilliseconds());
}
return srv;
}
////////////////////////////////////////////////////////////////////////////////
//// nsIInterfaceRequestor
NS_IMETHODIMP
Connection::GetInterface(const nsIID& aIID, void** _result) {
if (aIID.Equals(NS_GET_IID(nsIEventTarget))) {
nsIEventTarget* background = getAsyncExecutionTarget();
NS_IF_ADDREF(background);
*_result = background;
return NS_OK;
}
return NS_ERROR_NO_INTERFACE;
}
////////////////////////////////////////////////////////////////////////////////
//// mozIStorageConnection
NS_IMETHODIMP
Connection::Close() {
nsresult rv = ensureOperationSupported(SYNCHRONOUS);
if (NS_FAILED(rv)) {
return rv;
}
return synchronousClose();
}
nsresult Connection::synchronousClose() {
if (!connectionReady()) {
return NS_ERROR_NOT_INITIALIZED;
}
#ifdef DEBUG
// Since we're accessing mAsyncExecutionThread, we need to be on the opener
// thread. We make this check outside of debug code below in setClosedState,
// but this is here to be explicit.
bool onOpenerThread = false;
(void)threadOpenedOn->IsOnCurrentThread(&onOpenerThread);
MOZ_ASSERT(onOpenerThread);
#endif // DEBUG
// Make sure we have not executed any asynchronous statements.
// If this fails, the mDBConn may be left open, resulting in a leak.
// We'll try to finalize the pending statements and close the connection.
if (isAsyncExecutionThreadAvailable()) {
#ifdef DEBUG
if (NS_IsMainThread()) {
nsCOMPtr<nsIXPConnect> xpc = nsIXPConnect::XPConnect();
Unused << xpc->DebugDumpJSStack(false, false, false);
}
#endif
MOZ_ASSERT(false,
"Close() was invoked on a connection that executed asynchronous "
"statements. "
"Should have used asyncClose().");
// Try to close the database regardless, to free up resources.
Unused << SpinningSynchronousClose();
return NS_ERROR_UNEXPECTED;
}
// setClosedState nullifies our connection pointer, so we take a raw pointer
// off it, to pass it through the close procedure.
sqlite3* nativeConn = mDBConn;
nsresult rv = setClosedState();
NS_ENSURE_SUCCESS(rv, rv);
return internalClose(nativeConn);
}
NS_IMETHODIMP
Connection::SpinningSynchronousClose() {
nsresult rv = ensureOperationSupported(SYNCHRONOUS);
if (NS_FAILED(rv)) {
return rv;
}
if (threadOpenedOn != NS_GetCurrentThread()) {
return NS_ERROR_NOT_SAME_THREAD;
}
// As currently implemented, we can't spin to wait for an existing AsyncClose.
// Our only existing caller will never have called close; assert if misused
// so that no new callers assume this works after an AsyncClose.
MOZ_DIAGNOSTIC_ASSERT(connectionReady());
if (!connectionReady()) {
return NS_ERROR_UNEXPECTED;
}
RefPtr<CloseListener> listener = new CloseListener();
rv = AsyncClose(listener);
NS_ENSURE_SUCCESS(rv, rv);
MOZ_ALWAYS_TRUE(SpinEventLoopUntil([&]() { return listener->mClosed; }));
MOZ_ASSERT(isClosed(), "The connection should be closed at this point");
return rv;
}
NS_IMETHODIMP
Connection::AsyncClose(mozIStorageCompletionCallback* aCallback) {
NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
// Check if AsyncClose or Close were already invoked.
if (!connectionReady()) {
return NS_ERROR_NOT_INITIALIZED;
}
nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
if (NS_FAILED(rv)) {
return rv;
}
// The two relevant factors at this point are whether we have a database
// connection and whether we have an async execution thread. Here's what the
// states mean and how we handle them:
//
// - (mDBConn && asyncThread): The expected case where we are either an
// async connection or a sync connection that has been used asynchronously.
// Either way the caller must call us and not Close(). Nothing surprising
// about this. We'll dispatch AsyncCloseConnection to the already-existing
// async thread.
//
// - (mDBConn && !asyncThread): A somewhat unusual case where the caller
// opened the connection synchronously and was planning to use it
// asynchronously, but never got around to using it asynchronously before
// needing to shutdown. This has been observed to happen for the cookie
// service in a case where Firefox shuts itself down almost immediately
// after startup (for unknown reasons). In the Firefox shutdown case,
// we may also fail to create a new async execution thread if one does not
// already exist. (nsThreadManager will refuse to create new threads when
// it has already been told to shutdown.) As such, we need to handle a
// failure to create the async execution thread by falling back to
// synchronous Close() and also dispatching the completion callback because
// at least Places likes to spin a nested event loop that depends on the
// callback being invoked.
//
// Note that we have considered not trying to spin up the async execution
// thread in this case if it does not already exist, but the overhead of
// thread startup (if successful) is significantly less expensive than the
// worst-case potential I/O hit of synchronously closing a database when we
// could close it asynchronously.
//
// - (!mDBConn && asyncThread): This happens in some but not all cases where
// OpenAsyncDatabase encountered a problem opening the database. If it
// happened in all cases AsyncInitDatabase would just shut down the thread
// directly and we would avoid this case. But it doesn't, so for simplicity
// and consistency AsyncCloseConnection knows how to handle this and we
// act like this was the (mDBConn && asyncThread) case in this method.
//
// - (!mDBConn && !asyncThread): The database was never successfully opened or
// Close() or AsyncClose() has already been called (at least) once. This is
// undeniably a misuse case by the caller. We could optimize for this
// case by adding an additional check of mAsyncExecutionThread without using
// getAsyncExecutionTarget() to avoid wastefully creating a thread just to
// shut it down. But this complicates the method for broken caller code
// whereas we're still correct and safe without the special-case.
nsIEventTarget* asyncThread = getAsyncExecutionTarget();
// Create our callback event if we were given a callback. This will
// eventually be dispatched in all cases, even if we fall back to Close() and
// the database wasn't open and we return an error. The rationale is that
// no existing consumer checks our return value and several of them like to
// spin nested event loops until the callback fires. Given that, it seems
// preferable for us to dispatch the callback in all cases. (Except the
// wrong thread misuse case we bailed on up above. But that's okay because
// that is statically wrong whereas these edge cases are dynamic.)
nsCOMPtr<nsIRunnable> completeEvent;
if (aCallback) {
completeEvent = newCompletionEvent(aCallback);
}
if (!asyncThread) {
// We were unable to create an async thread, so we need to fall back to
// using normal Close(). Since there is no async thread, Close() will
// not complain about that. (Close() may, however, complain if the
// connection is closed, but that's okay.)
if (completeEvent) {
// Closing the database is more important than returning an error code
// about a failure to dispatch, especially because all existing native
// callers ignore our return value.
Unused << NS_DispatchToMainThread(completeEvent.forget());
}
MOZ_ALWAYS_SUCCEEDS(synchronousClose());
// Return a success inconditionally here, since Close() is unlikely to fail
// and we want to reassure the consumer that its callback will be invoked.
return NS_OK;
}
// setClosedState nullifies our connection pointer, so we take a raw pointer
// off it, to pass it through the close procedure.
sqlite3* nativeConn = mDBConn;
rv = setClosedState();
NS_ENSURE_SUCCESS(rv, rv);
// Create and dispatch our close event to the background thread.
nsCOMPtr<nsIRunnable> closeEvent =
new AsyncCloseConnection(this, nativeConn, completeEvent);
rv = asyncThread->Dispatch(closeEvent, NS_DISPATCH_NORMAL);
NS_ENSURE_SUCCESS(rv, rv);
return NS_OK;
}
NS_IMETHODIMP
Connection::AsyncClone(bool aReadOnly,
mozIStorageCompletionCallback* aCallback) {
AUTO_PROFILER_LABEL("Connection::AsyncClone", OTHER);
NS_ENSURE_TRUE(NS_IsMainThread(), NS_ERROR_NOT_SAME_THREAD);
if (!connectionReady()) {
return NS_ERROR_NOT_INITIALIZED;
}
nsresult rv = ensureOperationSupported(ASYNCHRONOUS);
if (NS_FAILED(rv)) {
return rv;
}