storage/StorageBaseStatementInternal.cpp
author Gregory Szorc <gps@mozilla.com>
Fri, 27 Oct 2017 14:55:31 -0700
changeset 442301 5e5ee518a4b9d43e72c879e9d124aa432fb06e1a
parent 417235 312f7a5a2c08d394a2403c837e5ee546dd4103d7
child 468925 d7d2f08e051c3c355d41dc5c1ce1bd3ca55a43b9
permissions -rw-r--r--
Bug 1412431 - Remove support for MOZ_PREFLIGHT and MOZ_POSTFLIGHT; r=nalexander These variables are unused in the repo. The %_ALL variation is used for sccache, however. The last use of these variables was removed when support for MacOS universal builds was removed. Someone somewhere may be relying on this functionality. But I don't think it is worth continuing to support in client.mk. If someone really needs it, we can reintroduce support for the feature elsewhere, like in mach or via mozconfig support somehow. MozReview-Commit-ID: 4KznCmK3JTN

/* -*- 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)
  {
    NS_PRECONDITION(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()
: 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