dioxus/packages/interpreter/src/ts/native.ts

// This file provides an extended variant of the interpreter used for desktop and liveview interaction
//
// This file lives on the renderer, not the host. It's basically a polyfill over functionality that the host can't
// provide since it doesn't have access to the dom.

import { BaseInterpreter, NodeId } from "./core";
import { SerializedEvent, serializeEvent } from "./serialize";

// okay so, we've got this JSChannel thing from sledgehammer, implicitly imported into our scope
// we want to extend it, and it technically extends base intepreter. To make typescript happy,
// we're going to bind the JSChannel_ object to the JSChannel object, and then extend it
var JSChannel_: typeof BaseInterpreter;

// @ts-ignore - this is coming from the host
if (RawInterpreter !== undefined && RawInterpreter !== null) {
  // @ts-ignore - this is coming from the host
  JSChannel_ = RawInterpreter;
};

export class NativeInterpreter extends JSChannel_ {
  intercept_link_redirects: boolean;
  ipc: any;
  editsPath: string;

  // eventually we want to remove liveview and build it into the server-side-events of fullstack
  // however, for now we need to support it since SSE in fullstack doesn't exist yet
  liveview: boolean;

  constructor(editsPath: string) {
    super();
    this.editsPath = editsPath;
  }

  initialize(root: HTMLElement): void {
    this.intercept_link_redirects = true;
    this.liveview = false;

    // attach an event listener on the body that prevents file drops from navigating
    // this is because the browser will try to navigate to the file if it's dropped on the window
    window.addEventListener("dragover", function (e) {
      // // check which element is our target
      if (e.target instanceof Element && e.target.tagName != "INPUT") {
        e.preventDefault();
      }
    }, false);

    window.addEventListener("drop", function (e) {
      let target = e.target;

      if (!(target instanceof Element)) {
        return;
      }

      // Dropping a file on the window will navigate to the file, which we don't want
      e.preventDefault();
    }, false);

    // attach a listener to the route that listens for clicks and prevents the default file dialog
    window.addEventListener("click", (event) => {
      const target = event.target;
      if (target instanceof HTMLInputElement && target.getAttribute("type") === "file") {
        // Send a message to the host to open the file dialog if the target is a file input and has a dioxus id attached to it
        let target_id = getTargetId(target);
        if (target_id !== null) {
          const message = this.serializeIpcMessage("file_dialog", {
            event: "change&input",
            accept: target.getAttribute("accept"),
            directory: target.getAttribute("webkitdirectory") === "true",
            multiple: target.hasAttribute("multiple"),
            target: target_id,
            bubbles: event.bubbles,
          });
          this.ipc.postMessage(message);
        }

        // Prevent default regardless - we don't want file dialogs and we don't want the browser to navigate
        event.preventDefault();
      }
    });


    // @ts-ignore - wry gives us this
    this.ipc = window.ipc;

    // make sure we pass the handler to the base interpreter
    const handler: EventListener = (event) => this.handleEvent(event, event.type, true);
    super.initialize(root, handler);
  }

  serializeIpcMessage(method: string, params = {}) {
    return JSON.stringify({ method, params });
  }

  scrollTo(id: NodeId, behavior: ScrollBehavior) {
    const node = this.nodes[id];
    if (node instanceof HTMLElement) {
      node.scrollIntoView({ behavior });
    }
  }

  getClientRect(id: NodeId): { type: string; origin: number[]; size: number[]; } | undefined {
    const node = this.nodes[id];
    if (node instanceof HTMLElement) {
      const rect = node.getBoundingClientRect();
      return {
        type: "GetClientRect",
        origin: [rect.x, rect.y],
        size: [rect.width, rect.height],
      };
    }
  }

  setFocus(id: NodeId, focus: boolean) {
    const node = this.nodes[id];

    if (node instanceof HTMLElement) {
      if (focus) {
        node.focus();
      } else {
        node.blur();
      }
    }
  }

  // ignore the fact the base interpreter uses ptr + len but we use array...
  // @ts-ignore
  loadChild(array: number[]) {
    // iterate through each number and get that child
    let node = this.stack[this.stack.length - 1];

    for (let i = 0; i < array.length; i++) {
      let end = array[i];
      for (node = node.firstChild; end > 0; end--) {
        node = node.nextSibling;
      }
    }

    return node;
  }

  appendChildren(id: NodeId, many: number) {
    const root = this.nodes[id];
    const els = this.stack.splice(this.stack.length - many);

    for (let k = 0; k < many; k++) {
      root.appendChild(els[k]);
    }
  }

  handleEvent(event: Event, name: string, bubbles: boolean) {
    const target = event.target!;
    const realId = getTargetId(target)!;
    const contents = serializeEvent(event, target);

    // Handle the event on the virtualdom and then preventDefault if it also preventsDefault
    // Some listeners
    let body = {
      name: name,
      data: contents,
      element: realId,
      bubbles,
    };

    // Run any prevent defaults the user might've set
    // This is to support the prevent_default: "onclick" attribute that dioxus has had for a while, but is not necessary
    // now that we expose preventDefault to the virtualdom on desktop
    // Liveview will still need to use this
    this.preventDefaults(event, target);

    // liveview does not have syncronous event handling, so we need to send the event to the host
    if (this.liveview) {
      // Okay, so the user might've requested some files to be read
      if (target instanceof HTMLInputElement && (event.type === "change" || event.type === "input")) {
        if (target.getAttribute("type") === "file") {
          this.readFiles(target, contents, bubbles, realId, name);
        }
      }
    } else {

      const message = this.serializeIpcMessage("user_event", body);
      this.ipc.postMessage(message);

      // // Run the event handler on the virtualdom
      // // capture/prevent default of the event if the virtualdom wants to
      // const res = handleVirtualdomEventSync(JSON.stringify(body));

      // if (res.preventDefault) {
      //   event.preventDefault();
      // }

      // if (res.stopPropagation) {
      //   event.stopPropagation();
      // }
    }
  }



  // This should:
  // - prevent form submissions from navigating
  // - prevent anchor tags from navigating
  // - prevent buttons from submitting forms
  // - let the virtualdom attempt to prevent the event
  preventDefaults(event: Event, target: EventTarget) {
    let preventDefaultRequests: string | null = null;

    // Some events can be triggered on text nodes, which don't have attributes
    if (target instanceof Element) {
      preventDefaultRequests = target.getAttribute(`dioxus-prevent-default`);
    }

    if (preventDefaultRequests && preventDefaultRequests.includes(`on${event.type}`)) {
      event.preventDefault();
    }

    if (event.type === "submit") {
      event.preventDefault();
    }

    // Attempt to intercept if the event is a click
    if (target instanceof Element && event.type === "click") {
      this.handleClickNavigate(event, target, preventDefaultRequests);
    }
  }

  handleClickNavigate(event: Event, target: Element, preventDefaultRequests: string) {
    // todo call prevent default if it's the right type of event
    if (!this.intercept_link_redirects) {
      return;
    }

    // prevent buttons in forms from submitting the form
    if (target.tagName === "BUTTON" && event.type == "submit") {
      event.preventDefault();
    }

    // If the target is an anchor tag, we want to intercept the click too, to prevent the browser from navigating
    let a_element = target.closest("a");
    if (a_element == null) {
      return;
    }

    event.preventDefault();

    let elementShouldPreventDefault =
      preventDefaultRequests && preventDefaultRequests.includes(`onclick`);

    let aElementShouldPreventDefault = a_element.getAttribute(
      `dioxus-prevent-default`
    );

    let linkShouldPreventDefault =
      aElementShouldPreventDefault &&
      aElementShouldPreventDefault.includes(`onclick`);

    if (!elementShouldPreventDefault && !linkShouldPreventDefault) {
      const href = a_element.getAttribute("href");
      if (href !== "" && href !== null && href !== undefined) {
        this.ipc.postMessage(
          this.serializeIpcMessage("browser_open", { href })
        );
      }
    }
  }

  waitForRequest(headless: boolean) {
    fetch(new Request(this.editsPath))
      .then(response => response.arrayBuffer())
      .then(bytes => {
        // In headless mode, the requestAnimationFrame callback is never called, so we need to run the bytes directly
        if (headless) {
          // @ts-ignore
          this.run_from_bytes(bytes);
        } else {
          // @ts-ignore
          requestAnimationFrame(() => this.run_from_bytes(bytes));
        }
        this.waitForRequest(headless);
      });
  }


  //  A liveview only function
  // Desktop will intercept the event before it hits this
  async readFiles(target: HTMLInputElement, contents: SerializedEvent, bubbles: boolean, realId: NodeId, name: string) {
    let files = target.files!;
    let file_contents: { [name: string]: number[] } = {};

    for (let i = 0; i < files.length; i++) {
      const file = files[i];
      file_contents[file.name] = Array.from(
        new Uint8Array(await file.arrayBuffer())
      );
    }

    contents.files = { files: file_contents };

    const message = this.serializeIpcMessage("user_event", {
      name: name,
      element: realId,
      data: contents,
      bubbles,
    });

    this.ipc.postMessage(message);
  }
}

type EventSyncResult = {
  preventDefault: boolean;
  stopPropagation: boolean;
  stopImmediatePropagation: boolean;
  filesRequested: boolean;
};

// This function sends the event to the virtualdom and then waits for the virtualdom to process it
//
// However, it's not really suitable for liveview, because it's synchronous and will block the main thread
// We should definitely consider using a websocket if we want to block... or just not block on liveview
// Liveview is a little bit of a tricky beast
function handleVirtualdomEventSync(contents: string): EventSyncResult {
  // Handle the event on the virtualdom and then process whatever its output was
  const xhr = new XMLHttpRequest();

  // Serialize the event and send it to the custom protocol in the Rust side of things
  xhr.timeout = 1000;
  xhr.open("GET", "/handle/event.please", false);
  xhr.setRequestHeader("Content-Type", "application/json");
  xhr.send(contents);

  // Deserialize the response, and then prevent the default/capture the event if the virtualdom wants to
  return JSON.parse(xhr.responseText);
}

function getTargetId(target: EventTarget): NodeId | null {
  // Ensure that the target is a node, sometimes it's nota
  if (!(target instanceof Node)) {
    return null;
  }

  let ourTarget = target;
  let realId = null;

  while (realId == null) {
    if (ourTarget === null) {
      return null;
    }

    if (ourTarget instanceof Element) {
      realId = ourTarget.getAttribute(`data-dioxus-id`);
    }

    ourTarget = ourTarget.parentNode;
  }

  return parseInt(realId);
}


// function applyFileUpload() {
//   let inputs = document.querySelectorAll("input");
//   for (let input of inputs) {
//     if (!input.getAttribute("data-dioxus-file-listener")) {
//       // prevent file inputs from opening the file dialog on click
//       const type = input.getAttribute("type");
//       if (type === "file") {
//         input.setAttribute("data-dioxus-file-listener", true);
//         input.addEventListener("click", (event) => {
//           let target = event.target;
//           let target_id = find_real_id(target);
//           if (target_id !== null) {
//             const send = (event_name) => {
//               const message = window.interpreter.serializeIpcMessage("file_diolog", { accept: target.getAttribute("accept"), directory: target.getAttribute("webkitdirectory") === "true", multiple: target.hasAttribute("multiple"), target: parseInt(target_id), bubbles: event_bubbles(event_name), event: event_name });
//               window.ipc.postMessage(message);
//             };
//             send("change&input");
//           }
//           event.preventDefault();
//         });
//       }
//     }
// }