/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-

 * vim: sw=2 ts=2 sts=2 expandtab

 * 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 "StorageBaseStatementInternal.h"

#include "nsProxyRelease.h"

#include "mozStorageBindingParamsArray.h"

#include "mozStorageStatementData.h"

#include "mozStorageAsyncStatementExecution.h"

namespace mozilla {

namespace storage {

////////////////////////////////////////////////////////////////////////////////

//// Local Classes

/**

 * Used to finalize an asynchronous statement on the background thread.

 */

class AsyncStatementFinalizer : public Runnable

{

public:

  /**

   * Constructor for the event.

   *

   * @param aStatement

   *        We need the AsyncStatement to be able to get at the sqlite3_stmt;

   *        we only access/create it on the async thread.

   * @param aConnection

   *        We need the connection to know what thread to release the statement

   *        on.  We release the statement on that thread since releasing the

   *        statement might end up releasing the connection too.

   */

  AsyncStatementFinalizer(StorageBaseStatementInternal* aStatement,

                          Connection* aConnection)

    : Runnable("storage::AsyncStatementFinalizer")

    , mStatement(aStatement)

    , mConnection(aConnection)

  {

  }

  NS_IMETHOD Run() override

  {

    if (mStatement->mAsyncStatement) {

      sqlite3_finalize(mStatement->mAsyncStatement);

      mStatement->mAsyncStatement = nullptr;

    }

    nsCOMPtr<nsIThread> targetThread(mConnection->threadOpenedOn);

    NS_ProxyRelease(

      "AsyncStatementFinalizer::mStatement", targetThread, mStatement.forget());

    return NS_OK;

  }

private:

  RefPtr<StorageBaseStatementInternal> mStatement;

  RefPtr<Connection> mConnection;

};

/**

 * Finalize a sqlite3_stmt on the background thread for a statement whose

 * destructor was invoked and the statement was non-null.

 */

class LastDitchSqliteStatementFinalizer : public Runnable

{

public:

  /**

   * Event constructor.

   *

   * @param aConnection

   *        Used to keep the connection alive.  If we failed to do this, it

   *        is possible that the statement going out of scope invoking us

   *        might have the last reference to the connection and so trigger

   *        an attempt to close the connection which is doomed to fail

   *        (because the asynchronous execution thread must exist which will

   *        trigger the failure case).

   * @param aStatement

   *        The sqlite3_stmt to finalize.  This object takes ownership /

   *        responsibility for the instance and all other references to it

   *        should be forgotten.

   */

  LastDitchSqliteStatementFinalizer(RefPtr<Connection>& aConnection,

                                    sqlite3_stmt* aStatement)

    : Runnable("storage::LastDitchSqliteStatementFinalizer")

    , mConnection(aConnection)

    , mAsyncStatement(aStatement)

  {

    MOZ_ASSERT(aConnection, "You must provide a Connection");

  }

  NS_IMETHOD Run() override

  {

    (void)::sqlite3_finalize(mAsyncStatement);

    mAsyncStatement = nullptr;

    nsCOMPtr<nsIThread> target(mConnection->threadOpenedOn);

    (void)::NS_ProxyRelease(

      "LastDitchSqliteStatementFinalizer::mConnection",

      target, mConnection.forget());

    return NS_OK;

  }

private:

  RefPtr<Connection> mConnection;

  sqlite3_stmt *mAsyncStatement;

};

////////////////////////////////////////////////////////////////////////////////

//// StorageBaseStatementInternal

StorageBaseStatementInternal::StorageBaseStatementInternal()

: mNativeConnection(nullptr)

, mAsyncStatement(nullptr)

{

}

void

StorageBaseStatementInternal::asyncFinalize()

{

  nsIEventTarget *target = mDBConnection->getAsyncExecutionTarget();

  if (target) {

    // Attempt to finalize asynchronously

    nsCOMPtr<nsIRunnable> event =

      new AsyncStatementFinalizer(this, mDBConnection);

    // Dispatch. Note that dispatching can fail, typically if

    // we have a race condition with asyncClose(). It's ok,

    // let asyncClose() win.

    (void)target->Dispatch(event, NS_DISPATCH_NORMAL);

  }

  // If we cannot get the background thread,

  // mozStorageConnection::AsyncClose() has already been called and

  // the statement either has been or will be cleaned up by

  // internalClose().

}

void

StorageBaseStatementInternal::destructorAsyncFinalize()

{

  if (!mAsyncStatement)

    return;

  bool isOwningThread = false;

  (void)mDBConnection->threadOpenedOn->IsOnCurrentThread(&isOwningThread);

  if (isOwningThread) {

    // If we are the owning thread (currently that means we're also the

    // main thread), then we can get the async target and just dispatch

    // to it.

    nsIEventTarget *target = mDBConnection->getAsyncExecutionTarget();

    if (target) {

      nsCOMPtr<nsIRunnable> event =

        new LastDitchSqliteStatementFinalizer(mDBConnection, mAsyncStatement);

      (void)target->Dispatch(event, NS_DISPATCH_NORMAL);

    }

  } else {

    // If we're not the owning thread, assume we're the async thread, and

    // just run the statement.

    nsCOMPtr<nsIRunnable> event =

      new LastDitchSqliteStatementFinalizer(mDBConnection, mAsyncStatement);

    (void)event->Run();

  }

  // We might not be able to dispatch to the background thread,

  // presumably because it is being shutdown. Since said shutdown will

  // finalize the statement, we just need to clean-up around here.

  mAsyncStatement = nullptr;

}

NS_IMETHODIMP

StorageBaseStatementInternal::NewBindingParamsArray(

  mozIStorageBindingParamsArray **_array

)

{

  nsCOMPtr<mozIStorageBindingParamsArray> array = new BindingParamsArray(this);

  NS_ENSURE_TRUE(array, NS_ERROR_OUT_OF_MEMORY);

  array.forget(_array);

  return NS_OK;

}

NS_IMETHODIMP

StorageBaseStatementInternal::ExecuteAsync(

  mozIStorageStatementCallback *aCallback,

  mozIStoragePendingStatement **_stmt

)

{

  // We used to call Connection::ExecuteAsync but it takes a

  // mozIStorageBaseStatement signature because it is also a public API.  Since

  // our 'this' has no static concept of mozIStorageBaseStatement and Connection

  // would just QI it back across to a StorageBaseStatementInternal and the

  // actual logic is very simple, we now roll our own.

  nsTArray<StatementData> stmts(1);

  StatementData data;

  nsresult rv = getAsynchronousStatementData(data);

  NS_ENSURE_SUCCESS(rv, rv);

  NS_ENSURE_TRUE(stmts.AppendElement(data), NS_ERROR_OUT_OF_MEMORY);

  // Dispatch to the background

  return AsyncExecuteStatements::execute(stmts, mDBConnection,

                                         mNativeConnection, aCallback, _stmt);

}

NS_IMETHODIMP

StorageBaseStatementInternal::EscapeStringForLIKE(

  const nsAString &aValue,

  const char16_t aEscapeChar,

  nsAString &_escapedString

)

{

  const char16_t MATCH_ALL('%');

  const char16_t MATCH_ONE('_');

  _escapedString.Truncate(0);

  for (uint32_t i = 0; i < aValue.Length(); i++) {

    if (aValue[i] == aEscapeChar || aValue[i] == MATCH_ALL ||

        aValue[i] == MATCH_ONE) {

      _escapedString += aEscapeChar;

    }

    _escapedString += aValue[i];

  }

  return NS_OK;

}

} // namespace storage

} // namespace mozilla