debugger.mjs

/* Copyright 2012 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

const { OPS } = globalThis.pdfjsLib || (await import("pdfjs-lib"));

const opMap = Object.create(null);
for (const key in OPS) {
  opMap[OPS[key]] = key;
}

const FontInspector = (function FontInspectorClosure() {
  let fonts;
  let active = false;
  const fontAttribute = "data-font-name";
  function removeSelection() {
    const divs = document.querySelectorAll(`span[${fontAttribute}]`);
    for (const div of divs) {
      div.className = "";
    }
  }
  function resetSelection() {
    const divs = document.querySelectorAll(`span[${fontAttribute}]`);
    for (const div of divs) {
      div.className = "debuggerHideText";
    }
  }
  function selectFont(fontName, show) {
    const divs = document.querySelectorAll(
      `span[${fontAttribute}=${fontName}]`
    );
    for (const div of divs) {
      div.className = show ? "debuggerShowText" : "debuggerHideText";
    }
  }
  function textLayerClick(e) {
    if (
      !e.target.dataset.fontName ||
      e.target.tagName.toUpperCase() !== "SPAN"
    ) {
      return;
    }
    const fontName = e.target.dataset.fontName;
    const selects = document.getElementsByTagName("input");
    for (const select of selects) {
      if (select.dataset.fontName !== fontName) {
        continue;
      }
      select.checked = !select.checked;
      selectFont(fontName, select.checked);
      select.scrollIntoView();
    }
  }
  return {
    // Properties/functions needed by PDFBug.
    id: "FontInspector",
    name: "Font Inspector",
    panel: null,
    manager: null,
    init() {
      const panel = this.panel;
      const tmp = document.createElement("button");
      tmp.addEventListener("click", resetSelection);
      tmp.textContent = "Refresh";
      panel.append(tmp);

      fonts = document.createElement("div");
      panel.append(fonts);
    },
    cleanup() {
      fonts.textContent = "";
    },
    enabled: false,
    get active() {
      return active;
    },
    set active(value) {
      active = value;
      if (active) {
        document.body.addEventListener("click", textLayerClick, true);
        resetSelection();
      } else {
        document.body.removeEventListener("click", textLayerClick, true);
        removeSelection();
      }
    },
    // FontInspector specific functions.
    fontAdded(fontObj, url) {
      function properties(obj, list) {
        const moreInfo = document.createElement("table");
        for (const entry of list) {
          const tr = document.createElement("tr");
          const td1 = document.createElement("td");
          td1.textContent = entry;
          tr.append(td1);
          const td2 = document.createElement("td");
          td2.textContent = obj[entry].toString();
          tr.append(td2);
          moreInfo.append(tr);
        }
        return moreInfo;
      }

      const moreInfo = fontObj.css
        ? properties(fontObj, ["baseFontName"])
        : properties(fontObj, ["name", "type"]);

      const fontName = fontObj.loadedName;
      const font = document.createElement("div");
      const name = document.createElement("span");
      name.textContent = fontName;
      let download;
      if (!fontObj.css) {
        download = document.createElement("a");
        if (url) {
          url = /url\(['"]?([^)"']+)/.exec(url);
          download.href = url[1];
        } else if (fontObj.data) {
          download.href = URL.createObjectURL(
            new Blob([fontObj.data], { type: fontObj.mimetype })
          );
        }
        download.textContent = "Download";
      }

      const logIt = document.createElement("a");
      logIt.href = "";
      logIt.textContent = "Log";
      logIt.addEventListener("click", function (event) {
        event.preventDefault();
        console.log(fontObj);
      });
      const select = document.createElement("input");
      select.setAttribute("type", "checkbox");
      select.dataset.fontName = fontName;
      select.addEventListener("click", function () {
        selectFont(fontName, select.checked);
      });
      if (download) {
        font.append(select, name, " ", download, " ", logIt, moreInfo);
      } else {
        font.append(select, name, " ", logIt, moreInfo);
      }
      fonts.append(font);
      // Somewhat of a hack, should probably add a hook for when the text layer
      // is done rendering.
      setTimeout(() => {
        if (this.active) {
          resetSelection();
        }
      }, 2000);
    },
  };
})();

// Manages all the page steppers.
const StepperManager = (function StepperManagerClosure() {
  let steppers = [];
  let stepperDiv = null;
  let stepperControls = null;
  let stepperChooser = null;
  let breakPoints = Object.create(null);
  return {
    // Properties/functions needed by PDFBug.
    id: "Stepper",
    name: "Stepper",
    panel: null,
    manager: null,
    init() {
      const self = this;
      stepperControls = document.createElement("div");
      stepperChooser = document.createElement("select");
      stepperChooser.addEventListener("change", function (event) {
        self.selectStepper(this.value);
      });
      stepperControls.append(stepperChooser);
      stepperDiv = document.createElement("div");
      this.panel.append(stepperControls, stepperDiv);
      if (sessionStorage.getItem("pdfjsBreakPoints")) {
        breakPoints = JSON.parse(sessionStorage.getItem("pdfjsBreakPoints"));
      }
    },
    cleanup() {
      stepperChooser.textContent = "";
      stepperDiv.textContent = "";
      steppers = [];
    },
    enabled: false,
    active: false,
    // Stepper specific functions.
    create(pageIndex) {
      const debug = document.createElement("div");
      debug.id = "stepper" + pageIndex;
      debug.hidden = true;
      debug.className = "stepper";
      stepperDiv.append(debug);
      const b = document.createElement("option");
      b.textContent = "Page " + (pageIndex + 1);
      b.value = pageIndex;
      stepperChooser.append(b);
      const initBreakPoints = breakPoints[pageIndex] || [];
      const stepper = new Stepper(debug, pageIndex, initBreakPoints);
      steppers.push(stepper);
      if (steppers.length === 1) {
        this.selectStepper(pageIndex, false);
      }
      return stepper;
    },
    selectStepper(pageIndex, selectPanel) {
      pageIndex |= 0;
      if (selectPanel) {
        this.manager.selectPanel(this);
      }
      for (const stepper of steppers) {
        stepper.panel.hidden = stepper.pageIndex !== pageIndex;
      }
      for (const option of stepperChooser.options) {
        option.selected = (option.value | 0) === pageIndex;
      }
    },
    saveBreakPoints(pageIndex, bps) {
      breakPoints[pageIndex] = bps;
      sessionStorage.setItem("pdfjsBreakPoints", JSON.stringify(breakPoints));
    },
  };
})();

// The stepper for each page's operatorList.
class Stepper {
  // Shorter way to create element and optionally set textContent.
  #c(tag, textContent) {
    const d = document.createElement(tag);
    if (textContent) {
      d.textContent = textContent;
    }
    return d;
  }

  #simplifyArgs(args) {
    if (typeof args === "string") {
      const MAX_STRING_LENGTH = 75;
      return args.length <= MAX_STRING_LENGTH
        ? args
        : args.substring(0, MAX_STRING_LENGTH) + "...";
    }
    if (typeof args !== "object" || args === null) {
      return args;
    }
    if ("length" in args) {
      // array
      const MAX_ITEMS = 10,
        simpleArgs = [];
      let i, ii;
      for (i = 0, ii = Math.min(MAX_ITEMS, args.length); i < ii; i++) {
        simpleArgs.push(this.#simplifyArgs(args[i]));
      }
      if (i < args.length) {
        simpleArgs.push("...");
      }
      return simpleArgs;
    }
    const simpleObj = {};
    for (const key in args) {
      simpleObj[key] = this.#simplifyArgs(args[key]);
    }
    return simpleObj;
  }

  constructor(panel, pageIndex, initialBreakPoints) {
    this.panel = panel;
    this.breakPoint = 0;
    this.nextBreakPoint = null;
    this.pageIndex = pageIndex;
    this.breakPoints = initialBreakPoints;
    this.currentIdx = -1;
    this.operatorListIdx = 0;
    this.indentLevel = 0;
  }

  init(operatorList) {
    const panel = this.panel;
    const content = this.#c("div", "c=continue, s=step");
    const table = this.#c("table");
    content.append(table);
    table.cellSpacing = 0;
    const headerRow = this.#c("tr");
    table.append(headerRow);
    headerRow.append(
      this.#c("th", "Break"),
      this.#c("th", "Idx"),
      this.#c("th", "fn"),
      this.#c("th", "args")
    );
    panel.append(content);
    this.table = table;
    this.updateOperatorList(operatorList);
  }

  updateOperatorList(operatorList) {
    const self = this;

    function cboxOnClick() {
      const x = +this.dataset.idx;
      if (this.checked) {
        self.breakPoints.push(x);
      } else {
        self.breakPoints.splice(self.breakPoints.indexOf(x), 1);
      }
      StepperManager.saveBreakPoints(self.pageIndex, self.breakPoints);
    }

    const MAX_OPERATORS_COUNT = 15000;
    if (this.operatorListIdx > MAX_OPERATORS_COUNT) {
      return;
    }

    const chunk = document.createDocumentFragment();
    const operatorsToDisplay = Math.min(
      MAX_OPERATORS_COUNT,
      operatorList.fnArray.length
    );
    for (let i = this.operatorListIdx; i < operatorsToDisplay; i++) {
      const line = this.#c("tr");
      line.className = "line";
      line.dataset.idx = i;
      chunk.append(line);
      const checked = this.breakPoints.includes(i);
      const args = operatorList.argsArray[i] || [];

      const breakCell = this.#c("td");
      const cbox = this.#c("input");
      cbox.type = "checkbox";
      cbox.className = "points";
      cbox.checked = checked;
      cbox.dataset.idx = i;
      cbox.onclick = cboxOnClick;

      breakCell.append(cbox);
      line.append(breakCell, this.#c("td", i.toString()));
      const fn = opMap[operatorList.fnArray[i]];
      let decArgs = args;
      if (fn === "showText") {
        const glyphs = args[0];
        const charCodeRow = this.#c("tr");
        const fontCharRow = this.#c("tr");
        const unicodeRow = this.#c("tr");
        for (const glyph of glyphs) {
          if (typeof glyph === "object" && glyph !== null) {
            charCodeRow.append(this.#c("td", glyph.originalCharCode));
            fontCharRow.append(this.#c("td", glyph.fontChar));
            unicodeRow.append(this.#c("td", glyph.unicode));
          } else {
            // null or number
            const advanceEl = this.#c("td", glyph);
            advanceEl.classList.add("advance");
            charCodeRow.append(advanceEl);
            fontCharRow.append(this.#c("td"));
            unicodeRow.append(this.#c("td"));
          }
        }
        decArgs = this.#c("td");
        const table = this.#c("table");
        table.classList.add("showText");
        decArgs.append(table);
        table.append(charCodeRow, fontCharRow, unicodeRow);
      } else if (fn === "restore" && this.indentLevel > 0) {
        this.indentLevel--;
      }
      line.append(this.#c("td", " ".repeat(this.indentLevel * 2) + fn));
      if (fn === "save") {
        this.indentLevel++;
      }

      if (decArgs instanceof HTMLElement) {
        line.append(decArgs);
      } else {
        line.append(this.#c("td", JSON.stringify(this.#simplifyArgs(decArgs))));
      }
    }
    if (operatorsToDisplay < operatorList.fnArray.length) {
      const lastCell = this.#c("td", "...");
      lastCell.colspan = 4;
      chunk.append(lastCell);
    }
    this.operatorListIdx = operatorList.fnArray.length;
    this.table.append(chunk);
  }

  getNextBreakPoint() {
    this.breakPoints.sort((a, b) => a - b);
    for (const breakPoint of this.breakPoints) {
      if (breakPoint > this.currentIdx) {
        return breakPoint;
      }
    }
    return null;
  }

  breakIt(idx, callback) {
    StepperManager.selectStepper(this.pageIndex, true);
    this.currentIdx = idx;

    const listener = evt => {
      switch (evt.keyCode) {
        case 83: // step
          document.removeEventListener("keydown", listener);
          this.nextBreakPoint = this.currentIdx + 1;
          this.goTo(-1);
          callback();
          break;
        case 67: // continue
          document.removeEventListener("keydown", listener);
          this.nextBreakPoint = this.getNextBreakPoint();
          this.goTo(-1);
          callback();
          break;
      }
    };
    document.addEventListener("keydown", listener);
    this.goTo(idx);
  }

  goTo(idx) {
    const allRows = this.panel.getElementsByClassName("line");
    for (const row of allRows) {
      if ((row.dataset.idx | 0) === idx) {
        row.style.backgroundColor = "rgb(251,250,207)";
        row.scrollIntoView();
      } else {
        row.style.backgroundColor = null;
      }
    }
  }
}

const Stats = (function Stats() {
  let stats = [];
  function clear(node) {
    node.textContent = ""; // Remove any `node` contents from the DOM.
  }
  function getStatIndex(pageNumber) {
    for (const [i, stat] of stats.entries()) {
      if (stat.pageNumber === pageNumber) {
        return i;
      }
    }
    return false;
  }
  return {
    // Properties/functions needed by PDFBug.
    id: "Stats",
    name: "Stats",
    panel: null,
    manager: null,
    init() {},
    enabled: false,
    active: false,
    // Stats specific functions.
    add(pageNumber, stat) {
      if (!stat) {
        return;
      }
      const statsIndex = getStatIndex(pageNumber);
      if (statsIndex !== false) {
        stats[statsIndex].div.remove();
        stats.splice(statsIndex, 1);
      }
      const wrapper = document.createElement("div");
      wrapper.className = "stats";
      const title = document.createElement("div");
      title.className = "title";
      title.textContent = "Page: " + pageNumber;
      const statsDiv = document.createElement("div");
      statsDiv.textContent = stat.toString();
      wrapper.append(title, statsDiv);
      stats.push({ pageNumber, div: wrapper });
      stats.sort((a, b) => a.pageNumber - b.pageNumber);
      clear(this.panel);
      for (const entry of stats) {
        this.panel.append(entry.div);
      }
    },
    cleanup() {
      stats = [];
      clear(this.panel);
    },
  };
})();

// Manages all the debugging tools.
class PDFBug {
  static #buttons = [];

  static #activePanel = null;

  static tools = [FontInspector, StepperManager, Stats];

  static enable(ids) {
    const all = ids.length === 1 && ids[0] === "all";
    const tools = this.tools;
    for (const tool of tools) {
      if (all || ids.includes(tool.id)) {
        tool.enabled = true;
      }
    }
    if (!all) {
      // Sort the tools by the order they are enabled.
      tools.sort(function (a, b) {
        let indexA = ids.indexOf(a.id);
        indexA = indexA < 0 ? tools.length : indexA;
        let indexB = ids.indexOf(b.id);
        indexB = indexB < 0 ? tools.length : indexB;
        return indexA - indexB;
      });
    }
  }

  static init(container, ids) {
    this.loadCSS();
    this.enable(ids);
    /*
     * Basic Layout:
     * PDFBug
     *  Controls
     *  Panels
     *    Panel
     *    Panel
     *    ...
     */
    const ui = document.createElement("div");
    ui.id = "PDFBug";

    const controls = document.createElement("div");
    controls.setAttribute("class", "controls");
    ui.append(controls);

    const panels = document.createElement("div");
    panels.setAttribute("class", "panels");
    ui.append(panels);

    container.append(ui);
    container.style.right = "var(--panel-width)";

    // Initialize all the debugging tools.
    for (const tool of this.tools) {
      const panel = document.createElement("div");
      const panelButton = document.createElement("button");
      panelButton.textContent = tool.name;
      panelButton.addEventListener("click", event => {
        event.preventDefault();
        this.selectPanel(tool);
      });
      controls.append(panelButton);
      panels.append(panel);
      tool.panel = panel;
      tool.manager = this;
      if (tool.enabled) {
        tool.init();
      } else {
        panel.textContent =
          `${tool.name} is disabled. To enable add "${tool.id}" to ` +
          "the pdfBug parameter and refresh (separate multiple by commas).";
      }
      this.#buttons.push(panelButton);
    }
    this.selectPanel(0);
  }

  static loadCSS() {
    const { url } = import.meta;

    const link = document.createElement("link");
    link.rel = "stylesheet";
    link.href = url.replace(/\.mjs$/, ".css");

    document.head.append(link);
  }

  static cleanup() {
    for (const tool of this.tools) {
      if (tool.enabled) {
        tool.cleanup();
      }
    }
  }

  static selectPanel(index) {
    if (typeof index !== "number") {
      index = this.tools.indexOf(index);
    }
    if (index === this.#activePanel) {
      return;
    }
    this.#activePanel = index;
    for (const [j, tool] of this.tools.entries()) {
      const isActive = j === index;
      this.#buttons[j].classList.toggle("active", isActive);
      tool.active = isActive;
      tool.panel.hidden = !isActive;
    }
  }
}

globalThis.FontInspector = FontInspector;
globalThis.StepperManager = StepperManager;
globalThis.Stats = Stats;

export { PDFBug };