test_usageUnderflowTelemetry.js

Enable keyboard shortcuts

/**

 * Any copyright is dedicated to the Public Domain.

 * http://creativecommons.org/publicdomain/zero/1.0/

*/

// The quotamanager.usage_underflow event is recorded when the in-memory

// usage of a client goes negative. Seed the LocalStorage usage from a usage

// file that is lower than the real content, then clear the storage: the

// removal subtracts the real item sizes and the counter crosses zero in

// OriginInfo::LockedTruncateUsages (bug 1585978).

add_task(async function testSteps() {

  const key = "key1";

  const value = repeatChar(1000, ".");

  const realUsage = key.length + value.length;

  const seededUsage = 10;

  const principal = getDefaultPrincipal();

  const usageFile = getRelativeFile(

    "storage/default/http+++example.com/ls/usage"

);

  info("Setting prefs");

  Services.prefs.setBoolPref("dom.quotaManager.loadQuotaFromCache", false);

  Services.fog.initializeFOG();

  info("Stage 1 - Storing an item and flushing it to disk");

  let request = clear();

  await requestFinished(request);

  let storage = getLocalStorage(principal);

  storage.setItem(key, value);

  request = reset();

  await requestFinished(request);

is(

    await readUsageFromUsageFile(usageFile),

    realUsage,

    "Usage file holds the real usage"

);

is(

    Glean.quotamanager.hadTemporaryStorageUsageUnderflow.testGetValue(),

    false,

    "'Had underflow' boolean shall be false initially"

);

  info("Stage 2 - Replacing the usage file content with a lower counter");

  // Cookie 0x420a420a followed by big-endian int64 10, as UpdateUsageFile

  // would write it.

  await IOUtils.write(

    usageFile.path,

    new Uint8Array([

      0x42,

      0x0a,

      0x42,

      0x0a,

      0x00,

      0x00,

      0x00,

      0x00,

      0x00,

      0x00,

      0x00,

      seededUsage,

])

);

  info("Stage 3 - Initializing the origin from the usage file");

  request = initStorage();

  await requestFinished(request);

  request = initTemporaryStorage();

  await requestFinished(request);

  request = initTemporaryOrigin(persistenceFor(principal), principal, false);

  await requestFinished(request);

  request = getCachedOriginUsage(principal);

  await requestFinished(request);

  is(request.result, seededUsage, "In-memory usage seeded from the file");

  info("Stage 4 - Clearing the storage");

  storage = getLocalStorage(principal);

  storage.clear();

  request = resetClient(principal);

  await requestFinished(request);

  const events = Glean.quotamanager.usageUnderflow.testGetValue();

  is(events.length, 1, "One usage_underflow event recorded");

  const extra = events[0].extra;

is(

    extra.call_site,

    "LockedTruncateUsages",

    "Recorded from LockedTruncateUsages"

);

  is(extra.client, "ls", "Recorded for the LocalStorage client");

is(

    Number(extra.magnitude),

    Math.floor(Math.log2(realUsage - seededUsage)),

    "Magnitude is the order of the negative value"

);

  // The origin is the only one loaded, so the total temporary storage usage

  // went negative by the same amount.

  const globalEvents =

    Glean.quotamanager.temporaryStorageUsageUnderflow.testGetValue();

  is(globalEvents.length, 1, "One temporary_storage_usage_underflow event");

is(

    globalEvents[0].extra.call_site,

    "LockedTruncateUsages",

    "Total usage recorded from LockedTruncateUsages"

);

is(

    Number(globalEvents[0].extra.magnitude),

    Math.floor(Math.log2(realUsage - seededUsage)),

    "Total usage magnitude is the order of the negative value"

);

is(

    Glean.quotamanager.hadTemporaryStorageUsageUnderflow.testGetValue(),

    true,

    "'Had underflow' boolean shall be true"

);

});