14ed71fa1b
* fix: use render client id to track deleted render process hosts Instead of relying on OS process id, which may not be unique when a process is reused, we rely on the renderer client id passed by the content layer when starting the renderer process which is guaranteed to be unique for the lifetime of the app. * fix: store context id as int64_t Ensuring that it doesn't wrap easily with a large number of context creation on some malformed web pages.
116 lines
3.2 KiB
JavaScript
116 lines
3.2 KiB
JavaScript
'use strict'
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const v8Util = process.atomBinding('v8_util')
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const getOwnerKey = (webContents, contextId) => {
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return `${webContents.id}-${contextId}`
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}
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class ObjectsRegistry {
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constructor () {
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this.nextId = 0
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// Stores all objects by ref-counting.
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// (id) => {object, count}
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this.storage = {}
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// Stores the IDs of objects referenced by WebContents.
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// (ownerKey) => [id]
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this.owners = {}
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}
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// Register a new object and return its assigned ID. If the object is already
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// registered then the already assigned ID would be returned.
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add (webContents, contextId, obj) {
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// Get or assign an ID to the object.
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const id = this.saveToStorage(obj)
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// Add object to the set of referenced objects.
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const ownerKey = getOwnerKey(webContents, contextId)
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let owner = this.owners[ownerKey]
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if (!owner) {
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owner = this.owners[ownerKey] = new Set()
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this.registerDeleteListener(webContents, contextId)
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}
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if (!owner.has(id)) {
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owner.add(id)
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// Increase reference count if not referenced before.
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this.storage[id].count++
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}
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return id
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}
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// Get an object according to its ID.
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get (id) {
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const pointer = this.storage[id]
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if (pointer != null) return pointer.object
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}
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// Dereference an object according to its ID.
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// Note that an object may be double-freed (cleared when page is reloaded, and
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// then garbage collected in old page).
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remove (webContents, contextId, id) {
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const ownerKey = getOwnerKey(webContents, contextId)
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let owner = this.owners[ownerKey]
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if (owner) {
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// Remove the reference in owner.
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owner.delete(id)
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// Dereference from the storage.
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this.dereference(id)
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}
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}
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// Clear all references to objects refrenced by the WebContents.
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clear (webContents, contextId) {
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const ownerKey = getOwnerKey(webContents, contextId)
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let owner = this.owners[ownerKey]
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if (!owner) return
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for (let id of owner) this.dereference(id)
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delete this.owners[ownerKey]
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}
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// Private: Saves the object into storage and assigns an ID for it.
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saveToStorage (object) {
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let id = v8Util.getHiddenValue(object, 'atomId')
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if (!id) {
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id = ++this.nextId
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this.storage[id] = {
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count: 0,
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object: object
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}
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v8Util.setHiddenValue(object, 'atomId', id)
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}
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return id
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}
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// Private: Dereference the object from store.
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dereference (id) {
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let pointer = this.storage[id]
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if (pointer == null) {
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return
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}
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pointer.count -= 1
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if (pointer.count === 0) {
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v8Util.deleteHiddenValue(pointer.object, 'atomId')
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delete this.storage[id]
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}
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}
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// Private: Clear the storage when renderer process is destroyed.
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registerDeleteListener (webContents, contextId) {
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// contextId => ${processHostId}-${contextCount}
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const processHostId = contextId.split('-')[0]
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const listener = (event, deletedProcessHostId) => {
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if (deletedProcessHostId &&
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deletedProcessHostId.toString() === processHostId) {
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webContents.removeListener('render-view-deleted', listener)
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this.clear(webContents, contextId)
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}
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}
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webContents.on('render-view-deleted', listener)
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}
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}
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module.exports = new ObjectsRegistry()
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