polygerrit-ui/app/behaviors/docs-url-behavior/docs-url-behavior.html

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@license
Copyright (C) 2017 The Android Open Source Project

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

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<link rel="import" href="../base-url-behavior/base-url-behavior.html">
<script>
(function(window) {
  'use strict';

  const PROBE_PATH = '/Documentation/index.html';
  const DOCS_BASE_PATH = '/Documentation';

  let cachedPromise;

  window.Gerrit = window.Gerrit || {};

  /** @polymerBehavior Gerrit.DocsUrlBehavior */
  Gerrit.DocsUrlBehavior = [{

    /**
     * Get the docs base URL from either the server config or by probing.
     *
     * @param {Object} config The server config.
     * @param {!Object} restApi A REST API instance
     * @return {!Promise<string>} A promise that resolves with the docs base
     *     URL.
     */
    getDocsBaseUrl(config, restApi) {
      if (!cachedPromise) {
        cachedPromise = new Promise(resolve => {
          if (config && config.gerrit && config.gerrit.doc_url) {
            resolve(config.gerrit.doc_url);
          } else {
            restApi.probePath(this.getBaseUrl() + PROBE_PATH).then(ok => {
              resolve(ok ? (this.getBaseUrl() + DOCS_BASE_PATH) : null);
            });
          }
        });
      }
      return cachedPromise;
    },

    /** For testing only. */
    _clearDocsBaseUrlCache() {
      cachedPromise = undefined;
    },
  },
  Gerrit.BaseUrlBehavior,
  ];
})(window);
</script>