gecko-dev/remote/marionette/print.js

/* 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/. */

"use strict";

const EXPORTED_SYMBOLS = ["print"];

const { XPCOMUtils } = ChromeUtils.import(
  "resource://gre/modules/XPCOMUtils.jsm"
);

XPCOMUtils.defineLazyModuleGetters(this, {
  assert: "chrome://remote/content/shared/webdriver/Assert.jsm",
  clearInterval: "resource://gre/modules/Timer.jsm",
  setInterval: "resource://gre/modules/Timer.jsm",

  Log: "chrome://remote/content/shared/Log.jsm",
});

XPCOMUtils.defineLazyGetter(this, "logger", () =>
  Log.get(Log.TYPES.MARIONETTE)
);

this.print = {
  maxScaleValue: 2.0,
  minScaleValue: 0.1,
  letterPaperSizeCm: {
    width: 21.59,
    height: 27.94,
  },
};

print.addDefaultSettings = function(settings) {
  const {
    landscape = false,
    margin = {
      top: 1,
      bottom: 1,
      left: 1,
      right: 1,
    },
    page = print.letterPaperSizeCm,
    shrinkToFit = true,
    printBackground = false,
    scale = 1.0,
    pageRanges = [],
  } = settings;

  return {
    landscape,
    margin,
    page,
    shrinkToFit,
    printBackground,
    scale,
    pageRanges,
  };
};

function getPrintSettings(settings, filePath) {
  const psService = Cc["@mozilla.org/gfx/printsettings-service;1"].getService(
    Ci.nsIPrintSettingsService
  );

  let cmToInches = cm => cm / 2.54;
  const printSettings = psService.newPrintSettings;
  printSettings.isInitializedFromPrinter = true;
  printSettings.isInitializedFromPrefs = true;
  printSettings.outputFormat = Ci.nsIPrintSettings.kOutputFormatPDF;
  printSettings.printerName = "marionette";
  printSettings.printSilent = true;
  printSettings.printToFile = true;
  printSettings.toFileName = filePath;

  // Setting the paperSizeUnit to kPaperSizeMillimeters doesn't work on mac
  printSettings.paperSizeUnit = Ci.nsIPrintSettings.kPaperSizeInches;
  printSettings.paperWidth = cmToInches(settings.page.width);
  printSettings.paperHeight = cmToInches(settings.page.height);

  printSettings.marginBottom = cmToInches(settings.margin.bottom);
  printSettings.marginLeft = cmToInches(settings.margin.left);
  printSettings.marginRight = cmToInches(settings.margin.right);
  printSettings.marginTop = cmToInches(settings.margin.top);

  printSettings.printBGColors = settings.printBackground;
  printSettings.printBGImages = settings.printBackground;
  printSettings.scaling = settings.scale;
  printSettings.shrinkToFit = settings.shrinkToFit;

  printSettings.headerStrCenter = "";
  printSettings.headerStrLeft = "";
  printSettings.headerStrRight = "";
  printSettings.footerStrCenter = "";
  printSettings.footerStrLeft = "";
  printSettings.footerStrRight = "";

  // Override any os-specific unwriteable margins
  printSettings.unwriteableMarginTop = 0;
  printSettings.unwriteableMarginLeft = 0;
  printSettings.unwriteableMarginBottom = 0;
  printSettings.unwriteableMarginRight = 0;

  if (settings.landscape) {
    printSettings.orientation = Ci.nsIPrintSettings.kLandscapeOrientation;
  }

  if (settings.pageRanges?.length) {
    printSettings.pageRanges = parseRanges(settings.pageRanges);
  }

  return printSettings;
}

/**
 * Convert array of strings of the form ["1-3", "2-4", "7", "9-"] to an flat array of
 * limits, like [1, 4, 7, 7, 9, 2**31 - 1] (meaning 1-4, 7, 9-end)
 *
 * @param {Array.<string|number>} ranges
 *     Page ranges to print, e.g., ['1-5', '8', '11-13'].
 *     Defaults to the empty string, which means print all pages.
 *
 * @return {Array.<number>}
 *     Even-length array containing page range limits
 */
function parseRanges(ranges) {
  const MAX_PAGES = 0x7fffffff;

  if (ranges.length === 0) {
    return [];
  }

  let allLimits = [];

  for (let range of ranges) {
    let limits;
    if (typeof range !== "string") {
      // We got a single integer so the limits are just that page
      assert.positiveInteger(range);
      limits = [range, range];
    } else {
      // We got a string presumably of the form <int> | <int>? "-" <int>?
      const msg = `Expected a range of the form <int> or <int>-<int>, got ${range}`;

      limits = range.split("-").map(x => x.trim());
      assert.that(o => [1, 2].includes(o.length), msg)(limits);

      // Single numbers map to a range with that page at the start and the end
      if (limits.length == 1) {
        limits.push(limits[0]);
      }

      // Need to check that both limits are strings conisting only of
      // decimal digits (or empty strings)
      const assertNumeric = assert.that(o => /^\d*$/.test(o), msg);
      limits.every(x => assertNumeric(x));

      // Convert from strings representing numbers to actual numbers
      // If we don't have an upper bound, choose something very large;
      // the print code will later truncate this to the number of pages
      limits = limits.map((limitStr, i) => {
        if (limitStr == "") {
          return i == 0 ? 1 : MAX_PAGES;
        }
        return parseInt(limitStr);
      });
    }
    assert.that(
      x => x[0] <= x[1],
      "Lower limit ${parts[0]} is higher than upper limit ${parts[1]}"
    )(limits);

    allLimits.push(limits);
  }
  // Order by lower limit
  allLimits.sort((a, b) => a[0] - b[0]);
  let parsedRanges = [allLimits.shift()];
  for (let limits of allLimits) {
    let prev = parsedRanges[parsedRanges.length - 1];
    let prevMax = prev[1];
    let [min, max] = limits;
    if (min <= prevMax) {
      // min is inside previous range, so extend the max if needed
      if (max > prevMax) {
        prev[1] = max;
      }
    } else {
      // Otherwise we have a new range
      parsedRanges.push(limits);
    }
  }

  let rv = parsedRanges.flat();
  logger.debug(`Got page ranges [${rv.join(", ")}]`);
  return rv;
}

print.printToFile = async function(browser, settings) {
  // Create a unique filename for the temporary PDF file
  const tempDir = await PathUtils.getTempDir();
  const basePath = PathUtils.join(tempDir, "marionette.pdf");
  const filePath = await PathUtils.createUniquePath(basePath);

  let printSettings = getPrintSettings(settings, filePath);

  await browser.browsingContext.print(printSettings);

  // Bug 1603739 - With e10s enabled the promise returned by print() resolves
  // too early, which means the file hasn't been completely written.
  await new Promise(resolve => {
    const DELAY_CHECK_FILE_COMPLETELY_WRITTEN = 100;

    let lastSize = 0;
    const timerId = setInterval(async () => {
      const fileInfo = await IOUtils.stat(filePath);
      if (lastSize > 0 && fileInfo.size == lastSize) {
        clearInterval(timerId);
        resolve();
      }
      lastSize = fileInfo.size;
    }, DELAY_CHECK_FILE_COMPLETELY_WRITTEN);
  });

  logger.debug(`PDF output written to ${filePath}`);
  return filePath;
};