DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Header

Mercurial (5f5af71fa66b)

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Mozilla Corporation. 
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Shawn Wilsher <me@shawnwilsher.com> (Original Author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "nsAutoPtr.h"
#include "prtime.h"

#include "sqlite3.h"

#include "mozIStorageStatementCallback.h"
#include "mozStorageBindingParams.h"
#include "mozStorageHelper.h"
#include "mozStorageResultSet.h"
#include "mozStorageRow.h"
#include "mozStorageConnection.h"
#include "mozStorageError.h"
#include "mozStoragePrivateHelpers.h"
#include "mozStorageStatementData.h"
#include "mozStorageAsyncStatementExecution.h"

namespace mozilla {
namespace storage {

/**
 * The following constants help batch rows into result sets.
 * MAX_MILLISECONDS_BETWEEN_RESULTS was chosen because any user-based task that
 * takes less than 200 milliseconds is considered to feel instantaneous to end
 * users.  MAX_ROWS_PER_RESULT was arbitrarily chosen to reduce the number of
 * dispatches to calling thread, while also providing reasonably-sized sets of
 * data for consumers.  Both of these constants are used because we assume that
 * consumers are trying to avoid blocking their execution thread for long
 * periods of time, and dispatching many small events to the calling thread will
 * end up blocking it.
 */
#define MAX_MILLISECONDS_BETWEEN_RESULTS 75
#define MAX_ROWS_PER_RESULT 15

////////////////////////////////////////////////////////////////////////////////
//// Local Classes

namespace {

typedef AsyncExecuteStatements::ExecutionState ExecutionState;

/**
 * Notifies a callback with a result set.
 */
class CallbackResultNotifier : public nsRunnable
{
public:
  CallbackResultNotifier(mozIStorageStatementCallback *aCallback,
                         mozIStorageResultSet *aResults,
                         AsyncExecuteStatements *aEventStatus) :
      mCallback(aCallback)
    , mResults(aResults)
    , mEventStatus(aEventStatus)
  {
  }

  NS_IMETHOD Run()
  {
    NS_ASSERTION(mCallback, "Trying to notify about results without a callback!");

    if (mEventStatus->shouldNotify())
      (void)mCallback->HandleResult(mResults);

    return NS_OK;
  }

private:
  mozIStorageStatementCallback *mCallback;
  nsCOMPtr<mozIStorageResultSet> mResults;
  nsRefPtr<AsyncExecuteStatements> mEventStatus;
};

/**
 * Notifies the calling thread that an error has occurred.
 */
class ErrorNotifier : public nsRunnable
{
public:
  ErrorNotifier(mozIStorageStatementCallback *aCallback,
                mozIStorageError *aErrorObj,
                AsyncExecuteStatements *aEventStatus) :
      mCallback(aCallback)
    , mErrorObj(aErrorObj)
    , mEventStatus(aEventStatus)
  {
  }

  NS_IMETHOD Run()
  {
    if (mEventStatus->shouldNotify() && mCallback)
      (void)mCallback->HandleError(mErrorObj);

    return NS_OK;
  }

private:
  mozIStorageStatementCallback *mCallback;
  nsCOMPtr<mozIStorageError> mErrorObj;
  nsRefPtr<AsyncExecuteStatements> mEventStatus;
};

/**
 * Notifies the calling thread that the statement has finished executing.  Keeps
 * the AsyncExecuteStatements instance alive long enough so that it does not
 * get destroyed on the async thread if there are no other references alive.
 */
class CompletionNotifier : public nsRunnable
{
public:
  /**
   * This takes ownership of the callback.  It is released on the thread this is
   * dispatched to (which should always be the calling thread).
   */
  CompletionNotifier(mozIStorageStatementCallback *aCallback,
                     ExecutionState aReason,
                     AsyncExecuteStatements *aKeepAsyncAlive)
    : mKeepAsyncAlive(aKeepAsyncAlive)
    , mCallback(aCallback)
    , mReason(aReason)
  {
  }

  NS_IMETHOD Run()
  {
    if (mCallback) {
      (void)mCallback->HandleCompletion(mReason);
      NS_RELEASE(mCallback);
    }

    return NS_OK;
  }

private:
  nsRefPtr<AsyncExecuteStatements> mKeepAsyncAlive;
  mozIStorageStatementCallback *mCallback;
  ExecutionState mReason;
};

} // anonymous namespace

////////////////////////////////////////////////////////////////////////////////
//// AsyncExecuteStatements

/* static */
nsresult
AsyncExecuteStatements::execute(StatementDataArray &aStatements,
                                Connection *aConnection,
                                mozIStorageStatementCallback *aCallback,
                                mozIStoragePendingStatement **_stmt)
{
  // Create our event to run in the background
  nsRefPtr<AsyncExecuteStatements> event =
    new AsyncExecuteStatements(aStatements, aConnection, aCallback);
  NS_ENSURE_TRUE(event, NS_ERROR_OUT_OF_MEMORY);

  // Dispatch it to the background
  nsIEventTarget *target = aConnection->getAsyncExecutionTarget();
  NS_ENSURE_TRUE(target, NS_ERROR_NOT_AVAILABLE);
  nsresult rv = target->Dispatch(event, NS_DISPATCH_NORMAL);
  NS_ENSURE_SUCCESS(rv, rv);

  // Return it as the pending statement object and track it.
  NS_ADDREF(*_stmt = event);
  return NS_OK;
}

AsyncExecuteStatements::AsyncExecuteStatements(StatementDataArray &aStatements,
                                               Connection *aConnection,
                                               mozIStorageStatementCallback *aCallback)
: mConnection(aConnection)
, mTransactionManager(nsnull)
, mCallback(aCallback)
, mCallingThread(::do_GetCurrentThread())
, mMaxWait(TimeDuration::FromMilliseconds(MAX_MILLISECONDS_BETWEEN_RESULTS))
, mIntervalStart(TimeStamp::Now())
, mState(PENDING)
, mCancelRequested(false)
, mMutex(aConnection->sharedAsyncExecutionMutex)
, mDBMutex(aConnection->sharedDBMutex)
{
  (void)mStatements.SwapElements(aStatements);
  NS_ASSERTION(mStatements.Length(), "We weren't given any statements!");
  NS_IF_ADDREF(mCallback);
}

bool
AsyncExecuteStatements::shouldNotify()
{
#ifdef DEBUG
  mMutex.AssertNotCurrentThreadOwns();

  PRBool onCallingThread = PR_FALSE;
  (void)mCallingThread->IsOnCurrentThread(&onCallingThread);
  NS_ASSERTION(onCallingThread, "runEvent not running on the calling thread!");
#endif

  // We do not need to acquire mMutex here because it can only ever be written
  // to on the calling thread, and the only thread that can call us is the
  // calling thread, so we know that our access is serialized.
  return !mCancelRequested;
}

bool
AsyncExecuteStatements::bindExecuteAndProcessStatement(StatementData &aData,
                                                       bool aLastStatement)
{
  mMutex.AssertNotCurrentThreadOwns();

  sqlite3_stmt *aStatement = nsnull;
  // This cannot fail; we are only called if it's available.
  (void)aData.getSqliteStatement(&aStatement);
  NS_ASSERTION(aStatement, "You broke the code; do not call here like that!");
  BindingParamsArray *paramsArray(aData);

  // Iterate through all of our parameters, bind them, and execute.
  bool continueProcessing = true;
  BindingParamsArray::iterator itr = paramsArray->begin();
  BindingParamsArray::iterator end = paramsArray->end();
  while (itr != end && continueProcessing) {
    // Bind the data to our statement.
    nsCOMPtr<IStorageBindingParamsInternal> bindingInternal = 
      do_QueryInterface(*itr);
    nsCOMPtr<mozIStorageError> error = bindingInternal->bind(aStatement);
    if (error) {
      // Set our error state.
      mState = ERROR;

      // And notify.
      (void)notifyError(error);
      return false;
    }

    // Advance our iterator, execute, and then process the statement.
    itr++;
    bool lastStatement = aLastStatement && itr == end;
    continueProcessing = executeAndProcessStatement(aStatement, lastStatement);

    // Always reset our statement.
    (void)::sqlite3_reset(aStatement);
  }

  return continueProcessing;
}

bool
AsyncExecuteStatements::executeAndProcessStatement(sqlite3_stmt *aStatement,
                                                   bool aLastStatement)
{
  mMutex.AssertNotCurrentThreadOwns();

  // Execute our statement
  bool hasResults;
  do {
    hasResults = executeStatement(aStatement);

    // If we had an error, bail.
    if (mState == ERROR)
      return false;

    // If we have been canceled, there is no point in going on...
    {
      MutexAutoLock lockedScope(mMutex);
      if (mCancelRequested) {
        mState = CANCELED;
        return false;
      }
    }

    // Build our result set and notify if we got anything back and have a
    // callback to notify.
    if (mCallback && hasResults &&
        NS_FAILED(buildAndNotifyResults(aStatement))) {
      // We had an error notifying, so we notify on error and stop processing.
      mState = ERROR;

      // Notify, and stop processing statements.
      (void)notifyError(mozIStorageError::ERROR,
                        "An error occurred while notifying about results");

      return false;
    }
  } while (hasResults);

#ifdef DEBUG
  // Check to make sure that this statement was smart about what it did.
  checkAndLogStatementPerformance(aStatement);
#endif

  // If we are done, we need to set our state accordingly while we still hold
  // our mutex.  We would have already returned if we were canceled or had
  // an error at this point.
  if (aLastStatement)
    mState = COMPLETED;

  return true;
}

bool
AsyncExecuteStatements::executeStatement(sqlite3_stmt *aStatement)
{
  mMutex.AssertNotCurrentThreadOwns();

  while (true) {
    // lock the sqlite mutex so sqlite3_errmsg cannot change
    SQLiteMutexAutoLock lockedScope(mDBMutex);

    int rc = ::sqlite3_step(aStatement);
    // Stop if we have no more results.
    if (rc == SQLITE_DONE)
      return false;

    // If we got results, we can return now.
    if (rc == SQLITE_ROW)
      return true;

    // Some errors are not fatal, and we can handle them and continue.
    if (rc == SQLITE_BUSY) {
      // Don't hold the lock while we call outside our module.
      SQLiteMutexAutoUnlock unlockedScope(mDBMutex);

      // Yield, and try again
      (void)::PR_Sleep(PR_INTERVAL_NO_WAIT);
      continue;
    }

    // Set an error state.
    mState = ERROR;

    // Construct the error message before giving up the mutex (which we cannot
    // hold during the call to notifyError).
    sqlite3 *db = mConnection->GetNativeConnection();
    nsCOMPtr<mozIStorageError> errorObj(new Error(rc, ::sqlite3_errmsg(db)));
    // We cannot hold the DB mutex while calling notifyError.
    SQLiteMutexAutoUnlock unlockedScope(mDBMutex);
    (void)notifyError(errorObj);

    // Finally, indicate that we should stop processing.
    return false;
  }
}

nsresult
AsyncExecuteStatements::buildAndNotifyResults(sqlite3_stmt *aStatement)
{
  NS_ASSERTION(mCallback, "Trying to dispatch results without a callback!");
  mMutex.AssertNotCurrentThreadOwns();

  // Build result object if we need it.
  if (!mResultSet)
    mResultSet = new ResultSet();
  NS_ENSURE_TRUE(mResultSet, NS_ERROR_OUT_OF_MEMORY);

  nsRefPtr<Row> row(new Row());
  NS_ENSURE_TRUE(row, NS_ERROR_OUT_OF_MEMORY);

  nsresult rv = row->initialize(aStatement);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = mResultSet->add(row);
  NS_ENSURE_SUCCESS(rv, rv);

  // If we have hit our maximum number of allowed results, or if we have hit
  // the maximum amount of time we want to wait for results, notify the
  // calling thread about it.
  TimeStamp now = TimeStamp::Now();
  TimeDuration delta = now - mIntervalStart;
  if (mResultSet->rows() >= MAX_ROWS_PER_RESULT || delta > mMaxWait) {
    // Notify the caller
    rv = notifyResults();
    if (NS_FAILED(rv))
      return NS_OK; // we'll try again with the next result

    // Reset our start time
    mIntervalStart = now;
  }

  return NS_OK;
}

nsresult
AsyncExecuteStatements::notifyComplete()
{
  mMutex.AssertNotCurrentThreadOwns();
  NS_ASSERTION(mState != PENDING,
               "Still in a pending state when calling Complete!");

  // Finalize our statements before we try to commit or rollback.  If we are
  // canceling and have statements that think they have pending work, the
  // rollback will fail.
  for (PRUint32 i = 0; i < mStatements.Length(); i++)
    mStatements[i].finalize();

  // Handle our transaction, if we have one
  if (mTransactionManager) {
    if (mState == COMPLETED) {
      nsresult rv = mTransactionManager->Commit();
      if (NS_FAILED(rv)) {
        mState = ERROR;
        (void)notifyError(mozIStorageError::ERROR,
                          "Transaction failed to commit");
      }
    }
    else {
      (void)mTransactionManager->Rollback();
    }
    delete mTransactionManager;
    mTransactionManager = nsnull;
  }

  // Always generate a completion notification; it is what guarantees that our
  // destruction does not happen here on the async thread.
  nsRefPtr<CompletionNotifier> completionEvent =
    new CompletionNotifier(mCallback, mState, this);
  NS_ENSURE_TRUE(completionEvent, NS_ERROR_OUT_OF_MEMORY);

  // We no longer own mCallback (the CompletionNotifier takes ownership).
  mCallback = nsnull;

  (void)mCallingThread->Dispatch(completionEvent, NS_DISPATCH_NORMAL);

  return NS_OK;
}

nsresult
AsyncExecuteStatements::notifyError(PRInt32 aErrorCode,
                                    const char *aMessage)
{
  mMutex.AssertNotCurrentThreadOwns();
  mDBMutex.assertNotCurrentThreadOwns();

  if (!mCallback)
    return NS_OK;

  nsCOMPtr<mozIStorageError> errorObj(new Error(aErrorCode, aMessage));
  NS_ENSURE_TRUE(errorObj, NS_ERROR_OUT_OF_MEMORY);

  return notifyError(errorObj);
}

nsresult
AsyncExecuteStatements::notifyError(mozIStorageError *aError)
{
  mMutex.AssertNotCurrentThreadOwns();
  mDBMutex.assertNotCurrentThreadOwns();

  if (!mCallback)
    return NS_OK;

  nsRefPtr<ErrorNotifier> notifier =
    new ErrorNotifier(mCallback, aError, this);
  NS_ENSURE_TRUE(notifier, NS_ERROR_OUT_OF_MEMORY);

  return mCallingThread->Dispatch(notifier, NS_DISPATCH_NORMAL);
}

nsresult
AsyncExecuteStatements::notifyResults()
{
  mMutex.AssertNotCurrentThreadOwns();
  NS_ASSERTION(mCallback, "notifyResults called without a callback!");

  nsRefPtr<CallbackResultNotifier> notifier =
    new CallbackResultNotifier(mCallback, mResultSet, this);
  NS_ENSURE_TRUE(notifier, NS_ERROR_OUT_OF_MEMORY);

  nsresult rv = mCallingThread->Dispatch(notifier, NS_DISPATCH_NORMAL);
  if (NS_SUCCEEDED(rv))
    mResultSet = nsnull; // we no longer own it on success
  return rv;
}

NS_IMPL_THREADSAFE_ISUPPORTS2(
  AsyncExecuteStatements,
  nsIRunnable,
  mozIStoragePendingStatement
)

////////////////////////////////////////////////////////////////////////////////
//// mozIStoragePendingStatement

NS_IMETHODIMP
AsyncExecuteStatements::Cancel()
{
#ifdef DEBUG
  PRBool onCallingThread = PR_FALSE;
  (void)mCallingThread->IsOnCurrentThread(&onCallingThread);
  NS_ASSERTION(onCallingThread, "Not canceling from the calling thread!");
#endif

  // If we have already canceled, we have an error, but always indicate that
  // we are trying to cancel.
  NS_ENSURE_FALSE(mCancelRequested, NS_ERROR_UNEXPECTED);

  {
    MutexAutoLock lockedScope(mMutex);

    // We need to indicate that we want to try and cancel now.
    mCancelRequested = true;
  }

  return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////
//// nsIRunnable

NS_IMETHODIMP
AsyncExecuteStatements::Run()
{
  // Do not run if we have been canceled.
  {
    MutexAutoLock lockedScope(mMutex);
    if (mCancelRequested)
      mState = CANCELED;
  }
  if (mState == CANCELED)
    return notifyComplete();

  // If there is more than one statement, run it in a transaction.  We assume
  // that we have been given write statements since getting a batch of read
  // statements doesn't make a whole lot of sense.
  // Additionally, if we have only one statement and it needs a transaction, we
  // will wrap it in one.
  if (mStatements.Length() > 1 || mStatements[0].needsTransaction()) {
    // We don't error if this failed because it's not terrible if it does.
    mTransactionManager = new mozStorageTransaction(mConnection, PR_FALSE,
                                                    mozIStorageConnection::TRANSACTION_IMMEDIATE);
  }

  // Execute each statement, giving the callback results if it returns any.
  for (PRUint32 i = 0; i < mStatements.Length(); i++) {
    bool finished = (i == (mStatements.Length() - 1));

    sqlite3_stmt *stmt;
    { // lock the sqlite mutex so sqlite3_errmsg cannot change
      SQLiteMutexAutoLock lockedScope(mDBMutex);

      int rc = mStatements[i].getSqliteStatement(&stmt);
      if (rc != SQLITE_OK) {
        // Set our error state.
        mState = ERROR;

        // Build the error object; can't call notifyError with the lock held
        sqlite3 *db = mConnection->GetNativeConnection();
        nsCOMPtr<mozIStorageError> errorObj(
          new Error(rc, ::sqlite3_errmsg(db))
        );
        {
          // We cannot hold the DB mutex and call notifyError.
          SQLiteMutexAutoUnlock unlockedScope(mDBMutex);
          (void)notifyError(errorObj);
        }
        break;
      }
    }

    // If we have parameters to bind, bind them, execute, and process.
    if (mStatements[i].hasParametersToBeBound()) {
      if (!bindExecuteAndProcessStatement(mStatements[i], finished))
        break;
    }
    // Otherwise, just execute and process the statement.
    else if (!executeAndProcessStatement(stmt, finished)) {
      break;
    }
  }

  // If we still have results that we haven't notified about, take care of
  // them now.
  if (mResultSet)
    (void)notifyResults();

  // Notify about completion
  return notifyComplete();
}

} // namespace storage
} // namespace mozilla