stylus/background/usercss-helper.js

/* global API_METHODS usercss chromeLocal styleManager */
'use strict';

(() => {
  API_METHODS.installUsercss = installUsercss;
  API_METHODS.editSaveUsercss = editSaveUsercss;
  API_METHODS.configUsercssVars = configUsercssVars;

  API_METHODS.buildUsercss = build;
  API_METHODS.openUsercssInstallPage = install;

  API_METHODS.findUsercss = find;

  const TEMP_CODE_PREFIX = 'tempUsercssCode';
  const TEMP_CODE_CLEANUP_DELAY = 60e3;
  let tempCodeLastWriteDate = 0;
  if (FIREFOX) {
    // the temp code is created on direct installation of usercss URLs in FF
    // and can be left behind in case the install page didn't open in time before
    // the extension was updated/reloaded/disabled or the browser was closed
    setTimeout(function poll() {
      if (Date.now() - tempCodeLastWriteDate < TEMP_CODE_CLEANUP_DELAY) {
        setTimeout(poll, TEMP_CODE_CLEANUP_DELAY);
        return;
      }
      chrome.storage.local.get(null, storage => {
        const leftovers = [];
        for (const key in storage) {
          if (key.startsWith(TEMP_CODE_PREFIX)) {
            leftovers.push(key);
          }
        }
        if (leftovers.length) {
          chrome.storage.local.remove(leftovers);
        }
      });
    }, TEMP_CODE_CLEANUP_DELAY);
  }

  function buildMeta(style) {
    if (style.usercssData) {
      return Promise.resolve(style);
    }
    try {
      const {sourceCode} = style;
      // allow sourceCode to be normalized
      delete style.sourceCode;
      return Promise.resolve(Object.assign(usercss.buildMeta(sourceCode), style));
    } catch (e) {
      return Promise.reject(e);
    }
  }

  function assignVars(style) {
    if (style.reason === 'config' && style.id) {
      return style;
    }
    return find(style)
      .then(dup => {
        if (dup) {
          style.id = dup.id;
          if (style.reason !== 'config') {
            // preserve style.vars during update
            usercss.assignVars(style, dup);
          }
        }
        return style;
      });
  }

  /**
   * Parse the source and find the duplication
   * @param _
   * @param {String} _.sourceCode
   * @param {Boolean=} _.checkDup
   * @param {Boolean=} _.metaOnly
   * @returns {Promise<{style, dup:Boolean?}>}
   */
  function build({
    sourceCode,
    checkDup,
    metaOnly,
    vars,
  }) {
    return Promise.resolve(usercss.buildMeta(sourceCode))
      .then(style =>
        Promise.all([
          metaOnly ? style : doBuild(style),
          checkDup ? find(style) : undefined
        ])
      )
      .then(([style, dup]) => ({style, dup}));

    function doBuild(style) {
      if (vars) {
        const oldStyle = {usercssData: {vars}};
        usercss.assignVars(style, oldStyle);
      }
      return usercss.buildCode(style);
    }
  }

  // Parse the source, apply customizations, report fatal/syntax errors
  function parse(style) {
    return fetchStyle()
      .then(buildMeta)
      .then(assignVars)
      .then(usercss.buildCode);

    function fetchStyle() {
      // restore if stripped by getStyleWithNoCode
      if (typeof style.sourceCode !== 'string') {
        return styleManager.get(style.id)
          .then(oldStyle => {
            style.sourceCode = oldStyle.sourceCode;
            return style;
          });
      }
      return Promise.resolve(style);
    }
  }

  function installUsercss(style) {
    return parse(style)
      .then(styleManager.installStyle);
  }

  function editSaveUsercss(style) {
    return parse(style)
      .then(styleManager.editSave);
  }

  function configUsercssVars(id, vars) {
    return styleManager.get(id)
      .then(style => {
        const newStyle = deepCopy(style);
        newStyle.usercssData.vars = vars;
        return usercss.buildCode(newStyle);
      })
      .then(style => styleManager.installStyle(style, 'config'))
      .then(style => style.usercssData.vars);
  }

  /**
   * @param {Style|{name:string, namespace:string}} styleOrData
   * @returns {Style}
   */
  function find(styleOrData) {
    if (styleOrData.id) {
      return styleManager.get(styleOrData.id);
    }
    const {name, namespace} = styleOrData.usercssData || styleOrData;
    return styleManager.getAllStyles().then(styleList => {
      for (const dup of styleList) {
        const data = dup.usercssData;
        if (!data) continue;
        if (data.name === name &&
            data.namespace === namespace) {
          return dup;
        }
      }
    });
  }

  function install({url, direct, downloaded, tab}, sender) {
    tab = tab !== undefined ? tab : sender.tab;
    url = url || tab.url;
    if (direct && !downloaded) {
      prefetchCodeForInstallation(tab.id, url);
    }
    return openURL({
      url: '/install-usercss.html' +
        '?updateUrl=' + encodeURIComponent(url) +
        '&tabId=' + tab.id +
        (direct ? '&direct=yes' : ''),
      index: tab.index + 1,
      openerTabId: tab.id,
      currentWindow: null,
    });
  }

  function prefetchCodeForInstallation(tabId, url) {
    const key = TEMP_CODE_PREFIX + tabId;
    tempCodeLastWriteDate = Date.now();
    Promise.all([
      download(url),
      chromeLocal.setValue(key, {loading: true}),
    ]).then(([code]) => {
      chromeLocal.setValue(key, code);
      setTimeout(() => chromeLocal.remove(key), TEMP_CODE_CLEANUP_DELAY);
    });
  }
})();