test_final_write_cleanup.js

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"use strict";

/**

 * This test ensures that we correctly clean up the session state when

 * writing with isFinalWrite, which is used on shutdown. It tests that each

 * tab's shistory is capped to a maximum number of preceding and succeeding

 * entries.

*/

const { SessionWriter } = ChromeUtils.importESModule(

  "resource:///modules/sessionstore/SessionWriter.sys.mjs"

);

// Make sure that we have a profile before initializing SessionFile.

do_get_profile();

const {

  SessionFile: { Paths },

} = ChromeUtils.importESModule(

  "resource:///modules/sessionstore/SessionFile.sys.mjs"

);

const MAX_ENTRIES = 9;

const URL = "http://example.com/#";

async function prepareWithLimit(back, fwd) {

  SessionWriter.init("empty", false, Paths, {

    maxSerializeBack: back,

    maxSerializeForward: fwd,

    maxUpgradeBackups: 3,

});

  await SessionWriter.wipe();

add_setup(async function () {

  registerCleanupFunction(() => SessionWriter.wipe());

});

function createSessionState(index) {

  // Generate the tab state entries and set the one-based

  // tab-state index to the middle session history entry.

  let tabState = { entries: [], index };

  for (let i = 0; i < MAX_ENTRIES; i++) {

    tabState.entries.push({ url: URL + i });

  return { windows: [{ tabs: [tabState] }] };

async function writeAndParse(state, path, options = {}) {

  // We clone here because `write` can change the data passed.

  let data = structuredClone(state);

  await SessionWriter.write(data, options);

  return IOUtils.readJSON(path, { decompress: true });

add_task(async function test_shistory_cap_none() {

  let state = createSessionState(5);

  // Don't limit the number of shistory entries.

  await prepareWithLimit(-1, -1);

  // Check that no caps are applied.

  let diskState = await writeAndParse(state, Paths.clean, {

    isFinalWrite: true,

});

  Assert.deepEqual(state, diskState, "no cap applied");

});

add_task(async function test_shistory_cap_middle() {

  let state = createSessionState(5);

  await prepareWithLimit(2, 3);

  // Cap is only applied on clean shutdown.

  let diskState = await writeAndParse(state, Paths.recovery);

  Assert.deepEqual(state, diskState, "no cap applied");

  // Check that the right number of shistory entries was discarded

  // and the shistory index updated accordingly.

  diskState = await writeAndParse(state, Paths.clean, { isFinalWrite: true });

  let tabState = state.windows[0].tabs[0];

  tabState.entries = tabState.entries.slice(2, 8);

  tabState.index = 3;

  Assert.deepEqual(state, diskState, "cap applied");

});

add_task(async function test_shistory_cap_lower_bound() {

  let state = createSessionState(1);

  await prepareWithLimit(5, 5);

  // Cap is only applied on clean shutdown.

  let diskState = await writeAndParse(state, Paths.recovery);

  Assert.deepEqual(state, diskState, "no cap applied");

  // Check that the right number of shistory entries was discarded.

  diskState = await writeAndParse(state, Paths.clean, { isFinalWrite: true });

  let tabState = state.windows[0].tabs[0];

  tabState.entries = tabState.entries.slice(0, 6);

  Assert.deepEqual(state, diskState, "cap applied");

});

add_task(async function test_shistory_cap_upper_bound() {

  let state = createSessionState(MAX_ENTRIES);

  await prepareWithLimit(5, 5);

  // Cap is only applied on clean shutdown.

  let diskState = await writeAndParse(state, Paths.recovery);

  Assert.deepEqual(state, diskState, "no cap applied");

  // Check that the right number of shistory entries was discarded

  // and the shistory index updated accordingly.

  diskState = await writeAndParse(state, Paths.clean, { isFinalWrite: true });

  let tabState = state.windows[0].tabs[0];

  tabState.entries = tabState.entries.slice(3);

  tabState.index = 6;

  Assert.deepEqual(state, diskState, "cap applied");

});