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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
const lazy = {};
ChromeUtils.defineLazyGetter(lazy, "logConsole", () =>
console.createInstance({
prefix: "MiniWindowChild",
maxLogLevel: Services.prefs.getBoolPref("browser.mini-window.log", false)
? "Debug"
: "Error",
})
);
ChromeUtils.defineESModuleGetters(lazy, {
DeferredTask: "resource://gre/modules/DeferredTask.sys.mjs",
});
// Scrolling fires continuously, so sample it on a timer instead of reading the
// position on every event.
const SCROLL_SAMPLE_MS = 100;
/**
* Content-side actor for Mini Window.
*/
export class MiniWindowChild extends JSWindowActorChild {
#lastScrollY = 0;
#scrollTask = null;
/**
* Start reporting upward scrolls to reveal the toolbar.
*/
#enableScrollReveal() {
this.#lastScrollY = this.#scrollY();
this.contentWindow?.addEventListener("scroll", this, {
capture: true,
passive: true,
});
}
handleEvent(event) {
if (event.type === "scroll") {
this.#scrollTask ??= new lazy.DeferredTask(
() => this.#onScroll(),
SCROLL_SAMPLE_MS
);
this.#scrollTask.arm();
}
}
/**
* @returns {number} The window's vertical scroll offset, read without
* flushing layout - this runs off a timer, so layout may well be dirty.
*/
#scrollY() {
let utils = this.contentWindow?.windowUtils;
if (!utils) {
return 0;
}
let scrollX = {},
scrollY = {};
utils.getScrollXY(false, scrollX, scrollY);
return scrollY.value;
}
/**
* Called when the content window is scrolled.
* The parent can't observe scrolling in remote content itself.
*/
#onScroll() {
let y = this.#scrollY();
if (y === this.#lastScrollY) {
return;
}
let up = y < this.#lastScrollY;
this.#lastScrollY = y;
this.sendAsyncMessage("Scrolled", { up });
}
didDestroy() {
this.#scrollTask?.disarm();
}
receiveMessage(message) {
switch (message.name) {
case "EnableScrollReveal":
this.#enableScrollReveal();
break;
case "GetSize":
return this.#getSize();
case "ScrollTo":
this.#scrollTo(message.data);
break;
}
return undefined;
}
/**
* Measures the whole page size.
*
* @returns {?{width: number, height: number}} The page size in content CSS
* px, or null if the content window is already gone.
*/
#getSize() {
let win = this.contentWindow;
let el = win?.document?.documentElement;
if (!win || !el) {
return null;
}
let size = {
width: Math.max(el.scrollWidth, win.innerWidth),
height: Math.max(el.scrollHeight, win.innerHeight),
};
lazy.logConsole.debug("size of original page is ", size);
return size;
}
/**
* Scroll the content to an absolute position. The parent normalizes scroll
* to 0,0 before framing, since the framing transform is applied relative to
* the page origin.
*
* @param {object} position - Absolute scroll offset, in content CSS px.
* @param {number} position.x
* @param {number} position.y
*/
#scrollTo({ x, y }) {
lazy.logConsole.debug("scroll position of original tab is ", { x, y });
try {
this.contentWindow?.scrollTo(x, y);
} catch (e) {
lazy.logConsole.error("Failed to scroll content", e);
}
}
}