diff options
Diffstat (limited to 'toolkit/components/downloads/DownloadStore.sys.mjs')
| -rw-r--r-- | toolkit/components/downloads/DownloadStore.sys.mjs | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/toolkit/components/downloads/DownloadStore.sys.mjs b/toolkit/components/downloads/DownloadStore.sys.mjs new file mode 100644 index 0000000000..63b8de9d23 --- /dev/null +++ b/toolkit/components/downloads/DownloadStore.sys.mjs @@ -0,0 +1,213 @@ +/* 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/. */ + +/** + * Handles serialization of Download objects and persistence into a file, so + * that the state of downloads can be restored across sessions. + * + * The file is stored in JSON format, without indentation. With indentation + * applied, the file would look like this: + * + * { + * "list": [ + * { + * "source": "http://www.example.com/download.txt", + * "target": "/home/user/Downloads/download.txt" + * }, + * { + * "source": { + * "url": "http://www.example.com/download.txt", + * "referrerInfo": serialized string represents referrerInfo object + * }, + * "target": "/home/user/Downloads/download-2.txt" + * } + * ] + * } + */ + +// Time after which insecure downloads that have not been dealt with on shutdown +// get removed (5 minutes). +const MAX_INSECURE_DOWNLOAD_AGE_MS = 5 * 60 * 1000; + +import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs"; + +const lazy = {}; + +ChromeUtils.defineESModuleGetters(lazy, { + Downloads: "resource://gre/modules/Downloads.sys.mjs", +}); + +XPCOMUtils.defineLazyGetter(lazy, "gTextDecoder", function () { + return new TextDecoder(); +}); + +XPCOMUtils.defineLazyGetter(lazy, "gTextEncoder", function () { + return new TextEncoder(); +}); + +/** + * Handles serialization of Download objects and persistence into a file, so + * that the state of downloads can be restored across sessions. + * + * @param aList + * DownloadList object to be populated or serialized. + * @param aPath + * String containing the file path where data should be saved. + */ +export var DownloadStore = function (aList, aPath) { + this.list = aList; + this.path = aPath; +}; + +DownloadStore.prototype = { + /** + * DownloadList object to be populated or serialized. + */ + list: null, + + /** + * String containing the file path where data should be saved. + */ + path: "", + + /** + * This function is called with a Download object as its first argument, and + * should return true if the item should be saved. + */ + onsaveitem: () => true, + + /** + * Loads persistent downloads from the file to the list. + * + * @return {Promise} + * @resolves When the operation finished successfully. + * @rejects JavaScript exception. + */ + load: function DS_load() { + return (async () => { + let bytes; + try { + bytes = await IOUtils.read(this.path); + } catch (ex) { + if (!(ex.name == "NotFoundError")) { + throw ex; + } + // If the file does not exist, there are no downloads to load. + return; + } + + // Set this to true when we make changes to the download list that should + // be reflected in the file again. + let storeChanges = false; + let removePromises = []; + let storeData = JSON.parse(lazy.gTextDecoder.decode(bytes)); + + // Create live downloads based on the static snapshot. + for (let downloadData of storeData.list) { + try { + let download = await lazy.Downloads.createDownload(downloadData); + + // Insecure downloads that have not been dealt with on shutdown should + // get cleaned up and removed from the download list on restart unless + // they are very new + if ( + download.error?.becauseBlockedByReputationCheck && + download.error.reputationCheckVerdict == "Insecure" && + Date.now() - download.startTime > MAX_INSECURE_DOWNLOAD_AGE_MS + ) { + removePromises.push(download.removePartialData()); + storeChanges = true; + continue; + } + + try { + if (!download.succeeded && !download.canceled && !download.error) { + // Try to restart the download if it was in progress during the + // previous session. Ignore errors. + download.start().catch(() => {}); + } else { + // If the download was not in progress, try to update the current + // progress from disk. This is relevant in case we retained + // partially downloaded data. + await download.refresh(); + } + } finally { + // Add the download to the list if we succeeded in creating it, + // after we have updated its initial state. + await this.list.add(download); + } + } catch (ex) { + // If an item is unrecognized, don't prevent others from being loaded. + console.error(ex); + } + } + + if (storeChanges) { + try { + await Promise.all(removePromises); + await this.save(); + } catch (ex) { + console.error(ex); + } + } + })(); + }, + + /** + * Saves persistent downloads from the list to the file. + * + * If an error occurs, the previous file is not deleted. + * + * @return {Promise} + * @resolves When the operation finished successfully. + * @rejects JavaScript exception. + */ + save: function DS_save() { + return (async () => { + let downloads = await this.list.getAll(); + + // Take a static snapshot of the current state of all the downloads. + let storeData = { list: [] }; + let atLeastOneDownload = false; + for (let download of downloads) { + try { + if (!this.onsaveitem(download)) { + continue; + } + + let serializable = download.toSerializable(); + if (!serializable) { + // This item cannot be persisted across sessions. + continue; + } + storeData.list.push(serializable); + atLeastOneDownload = true; + } catch (ex) { + // If an item cannot be converted to a serializable form, don't + // prevent others from being saved. + console.error(ex); + } + } + + if (atLeastOneDownload) { + // Create or overwrite the file if there are downloads to save. + let bytes = lazy.gTextEncoder.encode(JSON.stringify(storeData)); + await IOUtils.write(this.path, bytes, { + tmpPath: this.path + ".tmp", + }); + } else { + // Remove the file if there are no downloads to save at all. + try { + await IOUtils.remove(this.path); + } catch (ex) { + if (!(ex.name == "NotFoundError" || ex.name == "NotAllowedError")) { + throw ex; + } + // On Windows, we may get an access denied error instead of a no such + // file error if the file existed before, and was recently deleted. + } + } + })(); + }, +}; |