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/* 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/. */
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
setTimeout: "resource://gre/modules/Timer.sys.mjs",
});
import { EXIT_CODE } from "resource://gre/modules/BackgroundTasksManager.sys.mjs";
// Recursively removes a directory.
// Returns true if it succeeds, false otherwise.
function tryRemoveDir(aFile) {
try {
aFile.remove(true);
} catch (e) {
return false;
}
return true;
}
const FILE_CHECK_ITERATION_TIMEOUT_MS = 1000;
async function deleteChildDirectory(
parentDirPath,
childDirName,
secondsToWait
) {
if (!childDirName || !childDirName.length) {
return;
}
let targetFile = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
targetFile.initWithPath(parentDirPath);
targetFile.append(childDirName);
// We create the lock before the file is actually there so this task
// is the first one to acquire the lock. Otherwise a different task
// could be cleaning suffixes and start deleting the folder while this
// task is waiting for it to show up.
let dirLock = Cc["@mozilla.org/net/CachePurgeLock;1"].createInstance(
Ci.nsICachePurgeLock
);
let wasFirst = false;
let locked = false;
try {
dirLock.lock(childDirName);
locked = true;
wasFirst = !dirLock.isOtherInstanceRunning();
} catch (e) {
console.error("Failed to check dirLock");
}
if (!wasFirst) {
if (locked) {
dirLock.unlock();
locked = false;
}
console.error("Another instance is already purging this directory");
return;
}
// This backgroundtask process is spawned by the call to
// PR_CreateProcessDetached in CacheFileIOManager::SyncRemoveAllCacheFiles
// Only if spawning the process is successful is the cache folder renamed,
// so we need to wait until that is done.
let retryCount = 0;
while (!targetFile.exists()) {
if (retryCount * FILE_CHECK_ITERATION_TIMEOUT_MS > secondsToWait * 1000) {
// We don't know for sure if the folder was renamed or if a different
// task removed it already. The second variant is more likely but to
// be sure we'd have to consult a log file, which introduces
// more complexity.
console.error(`couldn't find cache folder ${targetFile.path}`);
if (locked) {
dirLock.unlock();
locked = false;
}
return;
}
await new Promise(resolve =>
lazy.setTimeout(resolve, FILE_CHECK_ITERATION_TIMEOUT_MS)
);
retryCount++;
console.error(`Cache folder attempt no ${retryCount}`);
}
if (!targetFile.isDirectory()) {
if (locked) {
dirLock.unlock();
locked = false;
}
throw new Error("Path was not a directory");
}
console.error(`started removing ${targetFile.path}`);
targetFile.remove(true);
console.error(`done removing ${targetFile.path}`);
if (locked) {
dirLock.unlock();
locked = false;
}
}
async function cleanupOtherDirectories(parentDirPath, otherFoldersSuffix) {
if (!otherFoldersSuffix || !otherFoldersSuffix.length) {
return;
}
let targetFile = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
targetFile.initWithPath(parentDirPath);
let entries = targetFile.directoryEntries;
while (entries.hasMoreElements()) {
let entry = entries.nextFile;
if (!entry.leafName.endsWith(otherFoldersSuffix)) {
continue;
}
let shouldProcessEntry = false;
// The folder could already be gone, so isDirectory could throw
try {
shouldProcessEntry = entry.isDirectory();
} catch (e) {}
if (!shouldProcessEntry) {
continue;
}
let dirLock = Cc["@mozilla.org/net/CachePurgeLock;1"].createInstance(
Ci.nsICachePurgeLock
);
let wasFirst = false;
try {
dirLock.lock(entry.leafName);
wasFirst = !dirLock.isOtherInstanceRunning();
} catch (e) {
console.error("Failed to check dirlock. Skipping folder");
dirLock.unlock();
continue;
}
if (!wasFirst) {
dirLock.unlock();
continue;
}
// Remove directory recursively.
let removedDir = tryRemoveDir(entry);
if (!removedDir && entry.exists()) {
// If first deletion of the directory failed, then we try again once more
// just in case.
removedDir = tryRemoveDir(entry);
}
console.error(
`Deletion of folder ${entry.leafName} - success=${removedDir}`
);
dirLock.unlock();
}
}
// Usage:
// removeDirectory parentDirPath childDirName secondsToWait [otherFoldersSuffix] [--test-sleep testSleep]
// arg0 arg1 arg2 arg3
// parentDirPath - The path to the parent directory that includes the target directory
// childDirName - The "leaf name" of the moved cache directory
// If empty, the background task will only purge folders that have the "otherFoldersSuffix".
// secondsToWait - String representing the number of seconds to wait for the cacheDir to be moved
// otherFoldersSuffix - [optional] The suffix of directories that should be removed
// When not empty, this task will also attempt to remove all directories in
// the parent dir that end with this suffix
// testSleep - [optional] A test-only argument to sleep for a given milliseconds before removal.
// This exists to test whether a long-running task can survive.
export async function runBackgroundTask(commandLine) {
const testSleep = Number.parseInt(
commandLine.handleFlagWithParam("test-sleep", false)
);
if (commandLine.length < 3) {
throw new Error("Insufficient arguments");
}
const parentDirPath = commandLine.getArgument(0);
const childDirName = commandLine.getArgument(1);
let secondsToWait = parseInt(commandLine.getArgument(2));
if (isNaN(secondsToWait)) {
secondsToWait = 10;
}
commandLine.removeArguments(0, 2);
let otherFoldersSuffix = "";
if (commandLine.length) {
otherFoldersSuffix = commandLine.getArgument(0);
commandLine.removeArguments(0, 0);
}
if (commandLine.length) {
throw new Error(
`${commandLine.length} unknown command args exist, closing.`
);
}
console.error(parentDirPath, childDirName, secondsToWait, otherFoldersSuffix);
if (!Number.isNaN(testSleep)) {
await new Promise(resolve => lazy.setTimeout(resolve, testSleep));
}
await deleteChildDirectory(parentDirPath, childDirName, secondsToWait);
await cleanupOtherDirectories(parentDirPath, otherFoldersSuffix);
// TODO: event telemetry with timings, and how often we have left over cache folders from previous runs.
return EXIT_CODE.SUCCESS;
}
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