Quelle HeapSnapshotFileUtils.js
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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/. */
// Heap snapshots are always saved in the temp directory, and have a regular // naming convention. This module provides helpers for working with heap // snapshot files in a safe manner. Because we attempt to avoid unnecessary // copies of the heap snapshot files by checking the local filesystem for a heap // snapshot file with the given snapshot id, we want to ensure that we are only // attempting to open heap snapshot files and not `~/.ssh/id_rsa`, for // example. Therefore, the RDP only talks about snapshot ids, or transfering the // bulk file data. A file path can be recovered from a snapshot id, which allows // one to check for the presence of the heap snapshot file on the local file // system, but we don't have to worry about opening arbitrary files. // // The heap snapshot file path conventions permits the following forms: // // $TEMP_DIRECTORY/XXXXXXXXXX.fxsnapshot // $TEMP_DIRECTORY/XXXXXXXXXX-XXXXX.fxsnapshot // // Where the strings of "X" are zero or more digits.
function getHeapSnapshotFileTemplate() { return PathUtils.join(PathUtils.tempDir, `${Date.now()}.fxsnapshot`);
}
/** * Get a unique temp file path for a new heap snapshot. The file is guaranteed * not to exist before this call. * * @returns String
*/
exports.getNewUniqueHeapSnapshotTempFilePath = function () { const file = new lazy.FileUtils.File(getHeapSnapshotFileTemplate()); // The call to createUnique will append "-N" after the leaf name (but before // the extension) until a new file is found and create it. This guarantees we // won't accidentally choose the same file twice.
file.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0o666); return file.path;
};
function isValidSnapshotFileId(snapshotId) { return /^\d+(\-\d+)?$/.test(snapshotId);
}
/** * Get the file path for the given snapshot id. * * @param {String} snapshotId * * @returns String | null
*/
exports.getHeapSnapshotTempFilePath = function (snapshotId) { // Don't want anyone sneaking "../../../.." strings into the snapshot id and // trying to make us open arbitrary files. if (!isValidSnapshotFileId(snapshotId)) { returnnull;
} return PathUtils.join(PathUtils.tempDir, snapshotId + ".fxsnapshot");
};
/** * Return true if we have the heap snapshot file for the given snapshot id on * the local file system. False is returned otherwise. * * @returns Promise<Boolean>
*/
exports.haveHeapSnapshotTempFile = function (snapshotId) { const path = exports.getHeapSnapshotTempFilePath(snapshotId); if (!path) { return Promise.resolve(false);
}
