gecko-dev/storage/mozStorageStatementData.h

151 lines
4.6 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=2 sts=2 et
* 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 mozStorageStatementData_h
#define mozStorageStatementData_h
#include "sqlite3.h"
#include "nsAutoPtr.h"
#include "nsTArray.h"
#include "nsIEventTarget.h"
#include "MainThreadUtils.h"
#include "mozStorageBindingParamsArray.h"
#include "mozIStorageBaseStatement.h"
#include "mozStorageConnection.h"
#include "StorageBaseStatementInternal.h"
struct sqlite3_stmt;
namespace mozilla {
namespace storage {
class StatementData
{
public:
StatementData(sqlite3_stmt *aStatement,
already_AddRefed<BindingParamsArray> aParamsArray,
StorageBaseStatementInternal *aStatementOwner)
: mStatement(aStatement)
, mParamsArray(aParamsArray)
, mStatementOwner(aStatementOwner)
{
NS_PRECONDITION(mStatementOwner, "Must have a statement owner!");
}
StatementData(const StatementData &aSource)
: mStatement(aSource.mStatement)
, mParamsArray(aSource.mParamsArray)
, mStatementOwner(aSource.mStatementOwner)
{
NS_PRECONDITION(mStatementOwner, "Must have a statement owner!");
}
StatementData()
: mStatement(nullptr)
{
}
~StatementData()
{
// We need to ensure that mParamsArray is released on the main thread,
// as the binding arguments may be XPConnect values, which are safe
// to release only on the main thread.
NS_ReleaseOnMainThread(mParamsArray.forget());
}
/**
* Return the sqlite statement, fetching it from the storage statement. In
* the case of AsyncStatements this may actually create the statement
*/
inline int getSqliteStatement(sqlite3_stmt **_stmt)
{
if (!mStatement) {
int rc = mStatementOwner->getAsyncStatement(&mStatement);
NS_ENSURE_TRUE(rc == SQLITE_OK, rc);
}
*_stmt = mStatement;
return SQLITE_OK;
}
operator BindingParamsArray *() const { return mParamsArray; }
/**
* NULLs out our sqlite3_stmt (it is held by the owner) after reseting it and
* clear all bindings to it. This is expected to occur on the async thread.
*/
inline void reset()
{
NS_PRECONDITION(mStatementOwner, "Must have a statement owner!");
#ifdef DEBUG
{
nsCOMPtr<nsIEventTarget> asyncThread =
mStatementOwner->getOwner()->getAsyncExecutionTarget();
// It's possible that we are shutting down the async thread, and this
// method would return nullptr as a result.
if (asyncThread) {
bool onAsyncThread;
NS_ASSERTION(NS_SUCCEEDED(asyncThread->IsOnCurrentThread(&onAsyncThread)) && onAsyncThread,
"This should only be running on the async thread!");
}
}
#endif
// In the AsyncStatement case we may never have populated mStatement if the
// AsyncExecuteStatements got canceled or a failure occurred in constructing
// the statement.
if (mStatement) {
(void)::sqlite3_reset(mStatement);
(void)::sqlite3_clear_bindings(mStatement);
mStatement = nullptr;
}
}
/**
* Indicates if this statement has parameters to be bound before it is
* executed.
*
* @return true if the statement has parameters to bind against, false
* otherwise.
*/
inline bool hasParametersToBeBound() const { return !!mParamsArray; }
/**
* Indicates the number of implicit statements generated by this statement
* requiring a transaction for execution. For example a single statement
* with N BindingParams will execute N implicit staments.
*
* @return number of statements requiring a transaction for execution.
*
* @note In the case of AsyncStatements this may actually create the
* statement.
*/
inline uint32_t needsTransaction()
{
MOZ_ASSERT(!NS_IsMainThread());
// Be sure to use the getSqliteStatement helper, since sqlite3_stmt_readonly
// can only analyze prepared statements and AsyncStatements are prepared
// lazily.
sqlite3_stmt *stmt;
int rc = getSqliteStatement(&stmt);
if (SQLITE_OK != rc || ::sqlite3_stmt_readonly(stmt)) {
return 0;
}
return mParamsArray ? mParamsArray->length() : 1;
}
private:
sqlite3_stmt *mStatement;
RefPtr<BindingParamsArray> mParamsArray;
/**
* We hold onto a reference of the statement's owner so it doesn't get
* destroyed out from under us.
*/
nsCOMPtr<StorageBaseStatementInternal> mStatementOwner;
};
} // namespace storage
} // namespace mozilla
#endif // mozStorageStatementData_h