tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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test_writer_starvation.js (3347B)

      1 /**
      2 * Any copyright is dedicated to the Public Domain.
      3 * http://creativecommons.org/publicdomain/zero/1.0/
      4 */
      5 /* eslint-disable mozilla/no-arbitrary-setTimeout */
      6 
      7 if (!this.window) {
      8  this.runTest = function () {
      9    todo(false, "Test disabled in xpcshell test suite for now");
     10    finishTest();
     11  };
     12 }
     13 
     14 var testGenerator = testSteps();
     15 
     16 function* testSteps() {
     17  const name = this.window ? window.location.pathname : "Splendid Test";
     18 
     19  // Needs to be enough to saturate the thread pool.
     20  const SYNC_REQUEST_COUNT = 25;
     21 
     22  let request = indexedDB.open(name, 1);
     23  request.onerror = errorHandler;
     24  request.onupgradeneeded = grabEventAndContinueHandler;
     25  request.onsuccess = grabEventAndContinueHandler;
     26  let event = yield undefined;
     27 
     28  let db = event.target.result;
     29  db.onerror = errorHandler;
     30 
     31  is(event.target.transaction.mode, "versionchange", "Correct mode");
     32 
     33  let objectStore = db.createObjectStore("foo", { autoIncrement: true });
     34 
     35  request = objectStore.add({});
     36  request.onerror = errorHandler;
     37  request.onsuccess = grabEventAndContinueHandler;
     38  event = yield undefined;
     39 
     40  let key = event.target.result;
     41  ok(key, "Got a key");
     42 
     43  yield undefined;
     44 
     45  let continueReading = true;
     46  let readerCount = 0;
     47  let writerCount = 0;
     48  let callbackCount = 0;
     49 
     50  // Generate a bunch of reads right away without returning to the event
     51  // loop.
     52  info("Generating " + SYNC_REQUEST_COUNT + " readonly requests");
     53 
     54  for (let i = 0; i < SYNC_REQUEST_COUNT; i++) {
     55    readerCount++;
     56    let request = db.transaction("foo").objectStore("foo").get(key);
     57    request.onsuccess = function (event) {
     58      is(event.target.transaction.mode, "readonly", "Correct mode");
     59      callbackCount++;
     60    };
     61  }
     62 
     63  while (continueReading) {
     64    readerCount++;
     65    info("Generating additional readonly request (" + readerCount + ")");
     66    let request = db.transaction("foo").objectStore("foo").get(key);
     67    request.onsuccess = function (event) {
     68      callbackCount++;
     69      info("Received readonly request callback (" + callbackCount + ")");
     70      is(event.target.transaction.mode, "readonly", "Correct mode");
     71      if (callbackCount == SYNC_REQUEST_COUNT) {
     72        writerCount++;
     73        info(
     74          "Generating 1 readwrite request with " +
     75            readerCount +
     76            " previous readonly requests"
     77        );
     78        let request = db
     79          .transaction("foo", "readwrite")
     80          .objectStore("foo")
     81          .add({}, readerCount);
     82        request.onsuccess = function (event) {
     83          callbackCount++;
     84          info("Received readwrite request callback (" + callbackCount + ")");
     85          is(event.target.transaction.mode, "readwrite", "Correct mode");
     86          is(
     87            event.target.result,
     88            callbackCount,
     89            "write callback came before later reads"
     90          );
     91        };
     92      } else if (callbackCount == SYNC_REQUEST_COUNT + 5) {
     93        continueReading = false;
     94      }
     95    };
     96 
     97    setTimeout(
     98      function () {
     99        testGenerator.next();
    100      },
    101      writerCount ? 1000 : 100
    102    );
    103    yield undefined;
    104  }
    105 
    106  while (callbackCount < readerCount + writerCount) {
    107    executeSoon(function () {
    108      testGenerator.next();
    109    });
    110    yield undefined;
    111  }
    112 
    113  is(callbackCount, readerCount + writerCount, "All requests accounted for");
    114 
    115  finishTest();
    116  yield undefined;
    117 }