// Copyright 2006 The Closure Library Authors. All Rights Reserved.
//
// 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.

/**
 * @fileoverview Class for parsing and formatting URIs.
 *
 * Use goog.Uri(string) to parse a URI string.  Use goog.Uri.create(...) to
 * create a new instance of the goog.Uri object from Uri parts.
 *
 * e.g: <code>var myUri = new goog.Uri(window.location);</code>
 *
 * Implements RFC 3986 for parsing/formatting URIs.
 * http://www.ietf.org/rfc/rfc3986.txt
 *
 * Some changes have been made to the interface (more like .NETs), though the
 * internal representation is now of un-encoded parts, this will change the
 * behavior slightly.
 *
 */

goog.provide('goog.Uri');
goog.provide('goog.Uri.QueryData');

goog.require('goog.array');
goog.require('goog.string');
goog.require('goog.structs');
goog.require('goog.structs.Map');
goog.require('goog.uri.utils');
goog.require('goog.uri.utils.ComponentIndex');
goog.require('goog.uri.utils.StandardQueryParam');



/**
 * This class contains setters and getters for the parts of the URI.
 * The <code>getXyz</code>/<code>setXyz</code> methods return the decoded part
 * -- so<code>goog.Uri.parse('/foo%20bar').getPath()</code> will return the
 * decoded path, <code>/foo bar</code>.
 *
 * Reserved characters (see RFC 3986 section 2.2) can be present in
 * their percent-encoded form in scheme, domain, and path URI components and
 * will not be auto-decoded. For example:
 * <code>goog.Uri.parse('rel%61tive/path%2fto/resource').getPath()</code> will
 * return <code>relative/path%2fto/resource</code>.
 *
 * The constructor accepts an optional unparsed, raw URI string.  The parser
 * is relaxed, so special characters that aren't escaped but don't cause
 * ambiguities will not cause parse failures.
 *
 * All setters return <code>this</code> and so may be chained, a la
 * <code>goog.Uri.parse('/foo').setFragment('part').toString()</code>.
 *
 * @param {*=} opt_uri Optional string URI to parse
 *        (use goog.Uri.create() to create a URI from parts), or if
 *        a goog.Uri is passed, a clone is created.
 * @param {boolean=} opt_ignoreCase If true, #getParameterValue will ignore
 * the case of the parameter name.
 *
 * @constructor
 * @struct
 */
goog.Uri = function(opt_uri, opt_ignoreCase) {
  /**
   * Scheme such as "http".
   * @private {string}
   */
  this.scheme_ = '';

  /**
   * User credentials in the form "username:password".
   * @private {string}
   */
  this.userInfo_ = '';

  /**
   * Domain part, e.g. "www.google.com".
   * @private {string}
   */
  this.domain_ = '';

  /**
   * Port, e.g. 8080.
   * @private {?number}
   */
  this.port_ = null;

  /**
   * Path, e.g. "/tests/img.png".
   * @private {string}
   */
  this.path_ = '';

  /**
   * The fragment without the #.
   * @private {string}
   */
  this.fragment_ = '';

  /**
   * Whether or not this Uri should be treated as Read Only.
   * @private {boolean}
   */
  this.isReadOnly_ = false;

  /**
   * Whether or not to ignore case when comparing query params.
   * @private {boolean}
   */
  this.ignoreCase_ = false;

  /**
   * Object representing query data.
   * @private {!goog.Uri.QueryData}
   */
  this.queryData_;

  // Parse in the uri string
  var m;
  if (opt_uri instanceof goog.Uri) {
    this.ignoreCase_ = goog.isDef(opt_ignoreCase) ?
        opt_ignoreCase : opt_uri.getIgnoreCase();
    this.setScheme(opt_uri.getScheme());
    this.setUserInfo(opt_uri.getUserInfo());
    this.setDomain(opt_uri.getDomain());
    this.setPort(opt_uri.getPort());
    this.setPath(opt_uri.getPath());
    this.setQueryData(opt_uri.getQueryData().clone());
    this.setFragment(opt_uri.getFragment());
  } else if (opt_uri && (m = goog.uri.utils.split(String(opt_uri)))) {
    this.ignoreCase_ = !!opt_ignoreCase;

    // Set the parts -- decoding as we do so.
    // COMPATABILITY NOTE - In IE, unmatched fields may be empty strings,
    // whereas in other browsers they will be undefined.
    this.setScheme(m[goog.uri.utils.ComponentIndex.SCHEME] || '', true);
    this.setUserInfo(m[goog.uri.utils.ComponentIndex.USER_INFO] || '', true);
    this.setDomain(m[goog.uri.utils.ComponentIndex.DOMAIN] || '', true);
    this.setPort(m[goog.uri.utils.ComponentIndex.PORT]);
    this.setPath(m[goog.uri.utils.ComponentIndex.PATH] || '', true);
    this.setQueryData(m[goog.uri.utils.ComponentIndex.QUERY_DATA] || '', true);
    this.setFragment(m[goog.uri.utils.ComponentIndex.FRAGMENT] || '', true);

  } else {
    this.ignoreCase_ = !!opt_ignoreCase;
    this.queryData_ = new goog.Uri.QueryData(null, null, this.ignoreCase_);
  }
};


/**
 * If true, we preserve the type of query parameters set programmatically.
 *
 * This means that if you set a parameter to a boolean, and then call
 * getParameterValue, you will get a boolean back.
 *
 * If false, we will coerce parameters to strings, just as they would
 * appear in real URIs.
 *
 * TODO(nicksantos): Remove this once people have time to fix all tests.
 *
 * @type {boolean}
 */
goog.Uri.preserveParameterTypesCompatibilityFlag = false;


/**
 * Parameter name added to stop caching.
 * @type {string}
 */
goog.Uri.RANDOM_PARAM = goog.uri.utils.StandardQueryParam.RANDOM;


/**
 * @return {string} The string form of the url.
 * @override
 */
goog.Uri.prototype.toString = function() {
  var out = [];

  var scheme = this.getScheme();
  if (scheme) {
    out.push(goog.Uri.encodeSpecialChars_(
        scheme, goog.Uri.reDisallowedInSchemeOrUserInfo_, true), ':');
  }

  var domain = this.getDomain();
  if (domain) {
    out.push('//');

    var userInfo = this.getUserInfo();
    if (userInfo) {
      out.push(goog.Uri.encodeSpecialChars_(
          userInfo, goog.Uri.reDisallowedInSchemeOrUserInfo_, true), '@');
    }

    out.push(goog.Uri.removeDoubleEncoding_(goog.string.urlEncode(domain)));

    var port = this.getPort();
    if (port != null) {
      out.push(':', String(port));
    }
  }

  var path = this.getPath();
  if (path) {
    if (this.hasDomain() && path.charAt(0) != '/') {
      out.push('/');
    }
    out.push(goog.Uri.encodeSpecialChars_(
        path,
        path.charAt(0) == '/' ?
            goog.Uri.reDisallowedInAbsolutePath_ :
            goog.Uri.reDisallowedInRelativePath_,
        true));
  }

  var query = this.getEncodedQuery();
  if (query) {
    out.push('?', query);
  }

  var fragment = this.getFragment();
  if (fragment) {
    out.push('#', goog.Uri.encodeSpecialChars_(
        fragment, goog.Uri.reDisallowedInFragment_));
  }
  return out.join('');
};


/**
 * Resolves the given relative URI (a goog.Uri object), using the URI
 * represented by this instance as the base URI.
 *
 * There are several kinds of relative URIs:<br>
 * 1. foo - replaces the last part of the path, the whole query and fragment<br>
 * 2. /foo - replaces the the path, the query and fragment<br>
 * 3. //foo - replaces everything from the domain on.  foo is a domain name<br>
 * 4. ?foo - replace the query and fragment<br>
 * 5. #foo - replace the fragment only
 *
 * Additionally, if relative URI has a non-empty path, all ".." and "."
 * segments will be resolved, as described in RFC 3986.
 *
 * @param {!goog.Uri} relativeUri The relative URI to resolve.
 * @return {!goog.Uri} The resolved URI.
 */
goog.Uri.prototype.resolve = function(relativeUri) {

  var absoluteUri = this.clone();

  // we satisfy these conditions by looking for the first part of relativeUri
  // that is not blank and applying defaults to the rest

  var overridden = relativeUri.hasScheme();

  if (overridden) {
    absoluteUri.setScheme(relativeUri.getScheme());
  } else {
    overridden = relativeUri.hasUserInfo();
  }

  if (overridden) {
    absoluteUri.setUserInfo(relativeUri.getUserInfo());
  } else {
    overridden = relativeUri.hasDomain();
  }

  if (overridden) {
    absoluteUri.setDomain(relativeUri.getDomain());
  } else {
    overridden = relativeUri.hasPort();
  }

  var path = relativeUri.getPath();
  if (overridden) {
    absoluteUri.setPort(relativeUri.getPort());
  } else {
    overridden = relativeUri.hasPath();
    if (overridden) {
      // resolve path properly
      if (path.charAt(0) != '/') {
        // path is relative
        if (this.hasDomain() && !this.hasPath()) {
          // RFC 3986, section 5.2.3, case 1
          path = '/' + path;
        } else {
          // RFC 3986, section 5.2.3, case 2
          var lastSlashIndex = absoluteUri.getPath().lastIndexOf('/');
          if (lastSlashIndex != -1) {
            path = absoluteUri.getPath().substr(0, lastSlashIndex + 1) + path;
          }
        }
      }
      path = goog.Uri.removeDotSegments(path);
    }
  }

  if (overridden) {
    absoluteUri.setPath(path);
  } else {
    overridden = relativeUri.hasQuery();
  }

  if (overridden) {
    absoluteUri.setQueryData(relativeUri.getDecodedQuery());
  } else {
    overridden = relativeUri.hasFragment();
  }

  if (overridden) {
    absoluteUri.setFragment(relativeUri.getFragment());
  }

  return absoluteUri;
};


/**
 * Clones the URI instance.
 * @return {!goog.Uri} New instance of the URI object.
 */
goog.Uri.prototype.clone = function() {
  return new goog.Uri(this);
};


/**
 * @return {string} The encoded scheme/protocol for the URI.
 */
goog.Uri.prototype.getScheme = function() {
  return this.scheme_;
};


/**
 * Sets the scheme/protocol.
 * @param {string} newScheme New scheme value.
 * @param {boolean=} opt_decode Optional param for whether to decode new value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setScheme = function(newScheme, opt_decode) {
  this.enforceReadOnly();
  this.scheme_ = opt_decode ? goog.Uri.decodeOrEmpty_(newScheme, true) :
      newScheme;

  // remove an : at the end of the scheme so somebody can pass in
  // window.location.protocol
  if (this.scheme_) {
    this.scheme_ = this.scheme_.replace(/:$/, '');
  }
  return this;
};


/**
 * @return {boolean} Whether the scheme has been set.
 */
goog.Uri.prototype.hasScheme = function() {
  return !!this.scheme_;
};


/**
 * @return {string} The decoded user info.
 */
goog.Uri.prototype.getUserInfo = function() {
  return this.userInfo_;
};


/**
 * Sets the userInfo.
 * @param {string} newUserInfo New userInfo value.
 * @param {boolean=} opt_decode Optional param for whether to decode new value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setUserInfo = function(newUserInfo, opt_decode) {
  this.enforceReadOnly();
  this.userInfo_ = opt_decode ? goog.Uri.decodeOrEmpty_(newUserInfo) :
                   newUserInfo;
  return this;
};


/**
 * @return {boolean} Whether the user info has been set.
 */
goog.Uri.prototype.hasUserInfo = function() {
  return !!this.userInfo_;
};


/**
 * @return {string} The decoded domain.
 */
goog.Uri.prototype.getDomain = function() {
  return this.domain_;
};


/**
 * Sets the domain.
 * @param {string} newDomain New domain value.
 * @param {boolean=} opt_decode Optional param for whether to decode new value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setDomain = function(newDomain, opt_decode) {
  this.enforceReadOnly();
  this.domain_ = opt_decode ? goog.Uri.decodeOrEmpty_(newDomain, true) :
      newDomain;
  return this;
};


/**
 * @return {boolean} Whether the domain has been set.
 */
goog.Uri.prototype.hasDomain = function() {
  return !!this.domain_;
};


/**
 * @return {?number} The port number.
 */
goog.Uri.prototype.getPort = function() {
  return this.port_;
};


/**
 * Sets the port number.
 * @param {*} newPort Port number. Will be explicitly casted to a number.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setPort = function(newPort) {
  this.enforceReadOnly();

  if (newPort) {
    newPort = Number(newPort);
    if (isNaN(newPort) || newPort < 0) {
      throw Error('Bad port number ' + newPort);
    }
    this.port_ = newPort;
  } else {
    this.port_ = null;
  }

  return this;
};


/**
 * @return {boolean} Whether the port has been set.
 */
goog.Uri.prototype.hasPort = function() {
  return this.port_ != null;
};


/**
  * @return {string} The decoded path.
 */
goog.Uri.prototype.getPath = function() {
  return this.path_;
};


/**
 * Sets the path.
 * @param {string} newPath New path value.
 * @param {boolean=} opt_decode Optional param for whether to decode new value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setPath = function(newPath, opt_decode) {
  this.enforceReadOnly();
  this.path_ = opt_decode ? goog.Uri.decodeOrEmpty_(newPath, true) : newPath;
  return this;
};


/**
 * @return {boolean} Whether the path has been set.
 */
goog.Uri.prototype.hasPath = function() {
  return !!this.path_;
};


/**
 * @return {boolean} Whether the query string has been set.
 */
goog.Uri.prototype.hasQuery = function() {
  return this.queryData_.toString() !== '';
};


/**
 * Sets the query data.
 * @param {goog.Uri.QueryData|string|undefined} queryData QueryData object.
 * @param {boolean=} opt_decode Optional param for whether to decode new value.
 *     Applies only if queryData is a string.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setQueryData = function(queryData, opt_decode) {
  this.enforceReadOnly();

  if (queryData instanceof goog.Uri.QueryData) {
    this.queryData_ = queryData;
    this.queryData_.setIgnoreCase(this.ignoreCase_);
  } else {
    if (!opt_decode) {
      // QueryData accepts encoded query string, so encode it if
      // opt_decode flag is not true.
      queryData = goog.Uri.encodeSpecialChars_(queryData,
                                               goog.Uri.reDisallowedInQuery_);
    }
    this.queryData_ = new goog.Uri.QueryData(queryData, null, this.ignoreCase_);
  }

  return this;
};


/**
 * Sets the URI query.
 * @param {string} newQuery New query value.
 * @param {boolean=} opt_decode Optional param for whether to decode new value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setQuery = function(newQuery, opt_decode) {
  return this.setQueryData(newQuery, opt_decode);
};


/**
 * @return {string} The encoded URI query, not including the ?.
 */
goog.Uri.prototype.getEncodedQuery = function() {
  return this.queryData_.toString();
};


/**
 * @return {string} The decoded URI query, not including the ?.
 */
goog.Uri.prototype.getDecodedQuery = function() {
  return this.queryData_.toDecodedString();
};


/**
 * Returns the query data.
 * @return {!goog.Uri.QueryData} QueryData object.
 */
goog.Uri.prototype.getQueryData = function() {
  return this.queryData_;
};


/**
 * @return {string} The encoded URI query, not including the ?.
 *
 * Warning: This method, unlike other getter methods, returns encoded
 * value, instead of decoded one.
 */
goog.Uri.prototype.getQuery = function() {
  return this.getEncodedQuery();
};


/**
 * Sets the value of the named query parameters, clearing previous values for
 * that key.
 *
 * @param {string} key The parameter to set.
 * @param {*} value The new value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setParameterValue = function(key, value) {
  this.enforceReadOnly();
  this.queryData_.set(key, value);
  return this;
};


/**
 * Sets the values of the named query parameters, clearing previous values for
 * that key.  Not new values will currently be moved to the end of the query
 * string.
 *
 * So, <code>goog.Uri.parse('foo?a=b&c=d&e=f').setParameterValues('c', ['new'])
 * </code> yields <tt>foo?a=b&e=f&c=new</tt>.</p>
 *
 * @param {string} key The parameter to set.
 * @param {*} values The new values. If values is a single
 *     string then it will be treated as the sole value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setParameterValues = function(key, values) {
  this.enforceReadOnly();

  if (!goog.isArray(values)) {
    values = [String(values)];
  }

  this.queryData_.setValues(key, values);

  return this;
};


/**
 * Returns the value<b>s</b> for a given cgi parameter as a list of decoded
 * query parameter values.
 * @param {string} name The parameter to get values for.
 * @return {!Array<?>} The values for a given cgi parameter as a list of
 *     decoded query parameter values.
 */
goog.Uri.prototype.getParameterValues = function(name) {
  return this.queryData_.getValues(name);
};


/**
 * Returns the first value for a given cgi parameter or undefined if the given
 * parameter name does not appear in the query string.
 * @param {string} paramName Unescaped parameter name.
 * @return {string|undefined} The first value for a given cgi parameter or
 *     undefined if the given parameter name does not appear in the query
 *     string.
 */
goog.Uri.prototype.getParameterValue = function(paramName) {
  // NOTE(nicksantos): This type-cast is a lie when
  // preserveParameterTypesCompatibilityFlag is set to true.
  // But this should only be set to true in tests.
  return /** @type {string|undefined} */ (this.queryData_.get(paramName));
};


/**
 * @return {string} The URI fragment, not including the #.
 */
goog.Uri.prototype.getFragment = function() {
  return this.fragment_;
};


/**
 * Sets the URI fragment.
 * @param {string} newFragment New fragment value.
 * @param {boolean=} opt_decode Optional param for whether to decode new value.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.setFragment = function(newFragment, opt_decode) {
  this.enforceReadOnly();
  this.fragment_ = opt_decode ? goog.Uri.decodeOrEmpty_(newFragment) :
                   newFragment;
  return this;
};


/**
 * @return {boolean} Whether the URI has a fragment set.
 */
goog.Uri.prototype.hasFragment = function() {
  return !!this.fragment_;
};


/**
 * Returns true if this has the same domain as that of uri2.
 * @param {!goog.Uri} uri2 The URI object to compare to.
 * @return {boolean} true if same domain; false otherwise.
 */
goog.Uri.prototype.hasSameDomainAs = function(uri2) {
  return ((!this.hasDomain() && !uri2.hasDomain()) ||
          this.getDomain() == uri2.getDomain()) &&
      ((!this.hasPort() && !uri2.hasPort()) ||
          this.getPort() == uri2.getPort());
};


/**
 * Adds a random parameter to the Uri.
 * @return {!goog.Uri} Reference to this Uri object.
 */
goog.Uri.prototype.makeUnique = function() {
  this.enforceReadOnly();
  this.setParameterValue(goog.Uri.RANDOM_PARAM, goog.string.getRandomString());

  return this;
};


/**
 * Removes the named query parameter.
 *
 * @param {string} key The parameter to remove.
 * @return {!goog.Uri} Reference to this URI object.
 */
goog.Uri.prototype.removeParameter = function(key) {
  this.enforceReadOnly();
  this.queryData_.remove(key);
  return this;
};


/**
 * Sets whether Uri is read only. If this goog.Uri is read-only,
 * enforceReadOnly_ will be called at the start of any function that may modify
 * this Uri.
 * @param {boolean} isReadOnly whether this goog.Uri should be read only.
 * @return {!goog.Uri} Reference to this Uri object.
 */
goog.Uri.prototype.setReadOnly = function(isReadOnly) {
  this.isReadOnly_ = isReadOnly;
  return this;
};


/**
 * @return {boolean} Whether the URI is read only.
 */
goog.Uri.prototype.isReadOnly = function() {
  return this.isReadOnly_;
};


/**
 * Checks if this Uri has been marked as read only, and if so, throws an error.
 * This should be called whenever any modifying function is called.
 */
goog.Uri.prototype.enforceReadOnly = function() {
  if (this.isReadOnly_) {
    throw Error('Tried to modify a read-only Uri');
  }
};


/**
 * Sets whether to ignore case.
 * NOTE: If there are already key/value pairs in the QueryData, and
 * ignoreCase_ is set to false, the keys will all be lower-cased.
 * @param {boolean} ignoreCase whether this goog.Uri should ignore case.
 * @return {!goog.Uri} Reference to this Uri object.
 */
goog.Uri.prototype.setIgnoreCase = function(ignoreCase) {
  this.ignoreCase_ = ignoreCase;
  if (this.queryData_) {
    this.queryData_.setIgnoreCase(ignoreCase);
  }
  return this;
};


/**
 * @return {boolean} Whether to ignore case.
 */
goog.Uri.prototype.getIgnoreCase = function() {
  return this.ignoreCase_;
};


//==============================================================================
// Static members
//==============================================================================


/**
 * Creates a uri from the string form.  Basically an alias of new goog.Uri().
 * If a Uri object is passed to parse then it will return a clone of the object.
 *
 * @param {*} uri Raw URI string or instance of Uri
 *     object.
 * @param {boolean=} opt_ignoreCase Whether to ignore the case of parameter
 * names in #getParameterValue.
 * @return {!goog.Uri} The new URI object.
 */
goog.Uri.parse = function(uri, opt_ignoreCase) {
  return uri instanceof goog.Uri ?
         uri.clone() : new goog.Uri(uri, opt_ignoreCase);
};


/**
 * Creates a new goog.Uri object from unencoded parts.
 *
 * @param {?string=} opt_scheme Scheme/protocol or full URI to parse.
 * @param {?string=} opt_userInfo username:password.
 * @param {?string=} opt_domain www.google.com.
 * @param {?number=} opt_port 9830.
 * @param {?string=} opt_path /some/path/to/a/file.html.
 * @param {string|goog.Uri.QueryData=} opt_query a=1&b=2.
 * @param {?string=} opt_fragment The fragment without the #.
 * @param {boolean=} opt_ignoreCase Whether to ignore parameter name case in
 *     #getParameterValue.
 *
 * @return {!goog.Uri} The new URI object.
 */
goog.Uri.create = function(opt_scheme, opt_userInfo, opt_domain, opt_port,
                           opt_path, opt_query, opt_fragment, opt_ignoreCase) {

  var uri = new goog.Uri(null, opt_ignoreCase);

  // Only set the parts if they are defined and not empty strings.
  opt_scheme && uri.setScheme(opt_scheme);
  opt_userInfo && uri.setUserInfo(opt_userInfo);
  opt_domain && uri.setDomain(opt_domain);
  opt_port && uri.setPort(opt_port);
  opt_path && uri.setPath(opt_path);
  opt_query && uri.setQueryData(opt_query);
  opt_fragment && uri.setFragment(opt_fragment);

  return uri;
};


/**
 * Resolves a relative Uri against a base Uri, accepting both strings and
 * Uri objects.
 *
 * @param {*} base Base Uri.
 * @param {*} rel Relative Uri.
 * @return {!goog.Uri} Resolved uri.
 */
goog.Uri.resolve = function(base, rel) {
  if (!(base instanceof goog.Uri)) {
    base = goog.Uri.parse(base);
  }

  if (!(rel instanceof goog.Uri)) {
    rel = goog.Uri.parse(rel);
  }

  return base.resolve(rel);
};


/**
 * Removes dot segments in given path component, as described in
 * RFC 3986, section 5.2.4.
 *
 * @param {string} path A non-empty path component.
 * @return {string} Path component with removed dot segments.
 */
goog.Uri.removeDotSegments = function(path) {
  if (path == '..' || path == '.') {
    return '';

  } else if (!goog.string.contains(path, './') &&
             !goog.string.contains(path, '/.')) {
    // This optimization detects uris which do not contain dot-segments,
    // and as a consequence do not require any processing.
    return path;

  } else {
    var leadingSlash = goog.string.startsWith(path, '/');
    var segments = path.split('/');
    var out = [];

    for (var pos = 0; pos < segments.length; ) {
      var segment = segments[pos++];

      if (segment == '.') {
        if (leadingSlash && pos == segments.length) {
          out.push('');
        }
      } else if (segment == '..') {
        if (out.length > 1 || out.length == 1 && out[0] != '') {
          out.pop();
        }
        if (leadingSlash && pos == segments.length) {
          out.push('');
        }
      } else {
        out.push(segment);
        leadingSlash = true;
      }
    }

    return out.join('/');
  }
};


/**
 * Decodes a value or returns the empty string if it isn't defined or empty.
 * @param {string|undefined} val Value to decode.
 * @param {boolean=} opt_preserveReserved If true, restricted characters will
 *     not be decoded.
 * @return {string} Decoded value.
 * @private
 */
goog.Uri.decodeOrEmpty_ = function(val, opt_preserveReserved) {
  // Don't use UrlDecode() here because val is not a query parameter.
  if (!val) {
    return '';
  }

  // decodeURI has the same output for '%2f' and '%252f'. We double encode %25
  // so that we can distinguish between the 2 inputs. This is later undone by
  // removeDoubleEncoding_.
  return opt_preserveReserved ?
      decodeURI(val.replace(/%25/g, '%2525')) : decodeURIComponent(val);
};


/**
 * If unescapedPart is non null, then escapes any characters in it that aren't
 * valid characters in a url and also escapes any special characters that
 * appear in extra.
 *
 * @param {*} unescapedPart The string to encode.
 * @param {RegExp} extra A character set of characters in [\01-\177].
 * @param {boolean=} opt_removeDoubleEncoding If true, remove double percent
 *     encoding.
 * @return {?string} null iff unescapedPart == null.
 * @private
 */
goog.Uri.encodeSpecialChars_ = function(unescapedPart, extra,
    opt_removeDoubleEncoding) {
  if (goog.isString(unescapedPart)) {
    var encoded = encodeURI(unescapedPart).
        replace(extra, goog.Uri.encodeChar_);
    if (opt_removeDoubleEncoding) {
      // encodeURI double-escapes %XX sequences used to represent restricted
      // characters in some URI components, remove the double escaping here.
      encoded = goog.Uri.removeDoubleEncoding_(encoded);
    }
    return encoded;
  }
  return null;
};


/**
 * Converts a character in [\01-\177] to its unicode character equivalent.
 * @param {string} ch One character string.
 * @return {string} Encoded string.
 * @private
 */
goog.Uri.encodeChar_ = function(ch) {
  var n = ch.charCodeAt(0);
  return '%' + ((n >> 4) & 0xf).toString(16) + (n & 0xf).toString(16);
};


/**
 * Removes double percent-encoding from a string.
 * @param  {string} doubleEncodedString String
 * @return {string} String with double encoding removed.
 * @private
 */
goog.Uri.removeDoubleEncoding_ = function(doubleEncodedString) {
  return doubleEncodedString.replace(/%25([0-9a-fA-F]{2})/g, '%$1');
};


/**
 * Regular expression for characters that are disallowed in the scheme or
 * userInfo part of the URI.
 * @type {RegExp}
 * @private
 */
goog.Uri.reDisallowedInSchemeOrUserInfo_ = /[#\/\?@]/g;


/**
 * Regular expression for characters that are disallowed in a relative path.
 * Colon is included due to RFC 3986 3.3.
 * @type {RegExp}
 * @private
 */
goog.Uri.reDisallowedInRelativePath_ = /[\#\?:]/g;


/**
 * Regular expression for characters that are disallowed in an absolute path.
 * @type {RegExp}
 * @private
 */
goog.Uri.reDisallowedInAbsolutePath_ = /[\#\?]/g;


/**
 * Regular expression for characters that are disallowed in the query.
 * @type {RegExp}
 * @private
 */
goog.Uri.reDisallowedInQuery_ = /[\#\?@]/g;


/**
 * Regular expression for characters that are disallowed in the fragment.
 * @type {RegExp}
 * @private
 */
goog.Uri.reDisallowedInFragment_ = /#/g;


/**
 * Checks whether two URIs have the same domain.
 * @param {string} uri1String First URI string.
 * @param {string} uri2String Second URI string.
 * @return {boolean} true if the two URIs have the same domain; false otherwise.
 */
goog.Uri.haveSameDomain = function(uri1String, uri2String) {
  // Differs from goog.uri.utils.haveSameDomain, since this ignores scheme.
  // TODO(gboyer): Have this just call goog.uri.util.haveSameDomain.
  var pieces1 = goog.uri.utils.split(uri1String);
  var pieces2 = goog.uri.utils.split(uri2String);
  return pieces1[goog.uri.utils.ComponentIndex.DOMAIN] ==
             pieces2[goog.uri.utils.ComponentIndex.DOMAIN] &&
         pieces1[goog.uri.utils.ComponentIndex.PORT] ==
             pieces2[goog.uri.utils.ComponentIndex.PORT];
};



/**
 * Class used to represent URI query parameters.  It is essentially a hash of
 * name-value pairs, though a name can be present more than once.
 *
 * Has the same interface as the collections in goog.structs.
 *
 * @param {?string=} opt_query Optional encoded query string to parse into
 *     the object.
 * @param {goog.Uri=} opt_uri Optional uri object that should have its
 *     cache invalidated when this object updates. Deprecated -- this
 *     is no longer required.
 * @param {boolean=} opt_ignoreCase If true, ignore the case of the parameter
 *     name in #get.
 * @constructor
 * @struct
 * @final
 */
goog.Uri.QueryData = function(opt_query, opt_uri, opt_ignoreCase) {
  /**
   * The map containing name/value or name/array-of-values pairs.
   * May be null if it requires parsing from the query string.
   *
   * We need to use a Map because we cannot guarantee that the key names will
   * not be problematic for IE.
   *
   * @private {goog.structs.Map<string, !Array<*>>}
   */
  this.keyMap_ = null;

  /**
   * The number of params, or null if it requires computing.
   * @private {?number}
   */
  this.count_ = null;

  /**
   * Encoded query string, or null if it requires computing from the key map.
   * @private {?string}
   */
  this.encodedQuery_ = opt_query || null;

  /**
   * If true, ignore the case of the parameter name in #get.
   * @private {boolean}
   */
  this.ignoreCase_ = !!opt_ignoreCase;
};


/**
 * If the underlying key map is not yet initialized, it parses the
 * query string and fills the map with parsed data.
 * @private
 */
goog.Uri.QueryData.prototype.ensureKeyMapInitialized_ = function() {
  if (!this.keyMap_) {
    this.keyMap_ = new goog.structs.Map();
    this.count_ = 0;
    if (this.encodedQuery_) {
      var self = this;
      goog.uri.utils.parseQueryData(this.encodedQuery_, function(name, value) {
        self.add(goog.string.urlDecode(name), value);
      });
    }
  }
};


/**
 * Creates a new query data instance from a map of names and values.
 *
 * @param {!goog.structs.Map<string, ?>|!Object} map Map of string parameter
 *     names to parameter value. If parameter value is an array, it is
 *     treated as if the key maps to each individual value in the
 *     array.
 * @param {goog.Uri=} opt_uri URI object that should have its cache
 *     invalidated when this object updates.
 * @param {boolean=} opt_ignoreCase If true, ignore the case of the parameter
 *     name in #get.
 * @return {!goog.Uri.QueryData} The populated query data instance.
 */
goog.Uri.QueryData.createFromMap = function(map, opt_uri, opt_ignoreCase) {
  var keys = goog.structs.getKeys(map);
  if (typeof keys == 'undefined') {
    throw Error('Keys are undefined');
  }

  var queryData = new goog.Uri.QueryData(null, null, opt_ignoreCase);
  var values = goog.structs.getValues(map);
  for (var i = 0; i < keys.length; i++) {
    var key = keys[i];
    var value = values[i];
    if (!goog.isArray(value)) {
      queryData.add(key, value);
    } else {
      queryData.setValues(key, value);
    }
  }
  return queryData;
};


/**
 * Creates a new query data instance from parallel arrays of parameter names
 * and values. Allows for duplicate parameter names. Throws an error if the
 * lengths of the arrays differ.
 *
 * @param {!Array<string>} keys Parameter names.
 * @param {!Array<?>} values Parameter values.
 * @param {goog.Uri=} opt_uri URI object that should have its cache
 *     invalidated when this object updates.
 * @param {boolean=} opt_ignoreCase If true, ignore the case of the parameter
 *     name in #get.
 * @return {!goog.Uri.QueryData} The populated query data instance.
 */
goog.Uri.QueryData.createFromKeysValues = function(
    keys, values, opt_uri, opt_ignoreCase) {
  if (keys.length != values.length) {
    throw Error('Mismatched lengths for keys/values');
  }
  var queryData = new goog.Uri.QueryData(null, null, opt_ignoreCase);
  for (var i = 0; i < keys.length; i++) {
    queryData.add(keys[i], values[i]);
  }
  return queryData;
};


/**
 * @return {?number} The number of parameters.
 */
goog.Uri.QueryData.prototype.getCount = function() {
  this.ensureKeyMapInitialized_();
  return this.count_;
};


/**
 * Adds a key value pair.
 * @param {string} key Name.
 * @param {*} value Value.
 * @return {!goog.Uri.QueryData} Instance of this object.
 */
goog.Uri.QueryData.prototype.add = function(key, value) {
  this.ensureKeyMapInitialized_();
  this.invalidateCache_();

  key = this.getKeyName_(key);
  var values = this.keyMap_.get(key);
  if (!values) {
    this.keyMap_.set(key, (values = []));
  }
  values.push(value);
  this.count_++;
  return this;
};


/**
 * Removes all the params with the given key.
 * @param {string} key Name.
 * @return {boolean} Whether any parameter was removed.
 */
goog.Uri.QueryData.prototype.remove = function(key) {
  this.ensureKeyMapInitialized_();

  key = this.getKeyName_(key);
  if (this.keyMap_.containsKey(key)) {
    this.invalidateCache_();

    // Decrement parameter count.
    this.count_ -= this.keyMap_.get(key).length;
    return this.keyMap_.remove(key);
  }
  return false;
};


/**
 * Clears the parameters.
 */
goog.Uri.QueryData.prototype.clear = function() {
  this.invalidateCache_();
  this.keyMap_ = null;
  this.count_ = 0;
};


/**
 * @return {boolean} Whether we have any parameters.
 */
goog.Uri.QueryData.prototype.isEmpty = function() {
  this.ensureKeyMapInitialized_();
  return this.count_ == 0;
};


/**
 * Whether there is a parameter with the given name
 * @param {string} key The parameter name to check for.
 * @return {boolean} Whether there is a parameter with the given name.
 */
goog.Uri.QueryData.prototype.containsKey = function(key) {
  this.ensureKeyMapInitialized_();
  key = this.getKeyName_(key);
  return this.keyMap_.containsKey(key);
};


/**
 * Whether there is a parameter with the given value.
 * @param {*} value The value to check for.
 * @return {boolean} Whether there is a parameter with the given value.
 */
goog.Uri.QueryData.prototype.containsValue = function(value) {
  // NOTE(arv): This solution goes through all the params even if it was the
  // first param. We can get around this by not reusing code or by switching to
  // iterators.
  var vals = this.getValues();
  return goog.array.contains(vals, value);
};


/**
 * Returns all the keys of the parameters. If a key is used multiple times
 * it will be included multiple times in the returned array
 * @return {!Array<string>} All the keys of the parameters.
 */
goog.Uri.QueryData.prototype.getKeys = function() {
  this.ensureKeyMapInitialized_();
  // We need to get the values to know how many keys to add.
  var vals = /** @type {!Array<*>} */ (this.keyMap_.getValues());
  var keys = this.keyMap_.getKeys();
  var rv = [];
  for (var i = 0; i < keys.length; i++) {
    var val = vals[i];
    for (var j = 0; j < val.length; j++) {
      rv.push(keys[i]);
    }
  }
  return rv;
};


/**
 * Returns all the values of the parameters with the given name. If the query
 * data has no such key this will return an empty array. If no key is given
 * all values wil be returned.
 * @param {string=} opt_key The name of the parameter to get the values for.
 * @return {!Array<?>} All the values of the parameters with the given name.
 */
goog.Uri.QueryData.prototype.getValues = function(opt_key) {
  this.ensureKeyMapInitialized_();
  var rv = [];
  if (goog.isString(opt_key)) {
    if (this.containsKey(opt_key)) {
      rv = goog.array.concat(rv, this.keyMap_.get(this.getKeyName_(opt_key)));
    }
  } else {
    // Return all values.
    var values = this.keyMap_.getValues();
    for (var i = 0; i < values.length; i++) {
      rv = goog.array.concat(rv, values[i]);
    }
  }
  return rv;
};


/**
 * Sets a key value pair and removes all other keys with the same value.
 *
 * @param {string} key Name.
 * @param {*} value Value.
 * @return {!goog.Uri.QueryData} Instance of this object.
 */
goog.Uri.QueryData.prototype.set = function(key, value) {
  this.ensureKeyMapInitialized_();
  this.invalidateCache_();

  // TODO(chrishenry): This could be better written as
  // this.remove(key), this.add(key, value), but that would reorder
  // the key (since the key is first removed and then added at the
  // end) and we would have to fix unit tests that depend on key
  // ordering.
  key = this.getKeyName_(key);
  if (this.containsKey(key)) {
    this.count_ -= this.keyMap_.get(key).length;
  }
  this.keyMap_.set(key, [value]);
  this.count_++;
  return this;
};


/**
 * Returns the first value associated with the key. If the query data has no
 * such key this will return undefined or the optional default.
 * @param {string} key The name of the parameter to get the value for.
 * @param {*=} opt_default The default value to return if the query data
 *     has no such key.
 * @return {*} The first string value associated with the key, or opt_default
 *     if there's no value.
 */
goog.Uri.QueryData.prototype.get = function(key, opt_default) {
  var values = key ? this.getValues(key) : [];
  if (goog.Uri.preserveParameterTypesCompatibilityFlag) {
    return values.length > 0 ? values[0] : opt_default;
  } else {
    return values.length > 0 ? String(values[0]) : opt_default;
  }
};


/**
 * Sets the values for a key. If the key already exists, this will
 * override all of the existing values that correspond to the key.
 * @param {string} key The key to set values for.
 * @param {!Array<?>} values The values to set.
 */
goog.Uri.QueryData.prototype.setValues = function(key, values) {
  this.remove(key);

  if (values.length > 0) {
    this.invalidateCache_();
    this.keyMap_.set(this.getKeyName_(key), goog.array.clone(values));
    this.count_ += values.length;
  }
};


/**
 * @return {string} Encoded query string.
 * @override
 */
goog.Uri.QueryData.prototype.toString = function() {
  if (this.encodedQuery_) {
    return this.encodedQuery_;
  }

  if (!this.keyMap_) {
    return '';
  }

  var sb = [];

  // In the past, we use this.getKeys() and this.getVals(), but that
  // generates a lot of allocations as compared to simply iterating
  // over the keys.
  var keys = this.keyMap_.getKeys();
  for (var i = 0; i < keys.length; i++) {
    var key = keys[i];
    var encodedKey = goog.string.urlEncode(key);
    var val = this.getValues(key);
    for (var j = 0; j < val.length; j++) {
      var param = encodedKey;
      // Ensure that null and undefined are encoded into the url as
      // literal strings.
      if (val[j] !== '') {
        param += '=' + goog.string.urlEncode(val[j]);
      }
      sb.push(param);
    }
  }

  return this.encodedQuery_ = sb.join('&');
};


/**
 * @return {string} Decoded query string.
 */
goog.Uri.QueryData.prototype.toDecodedString = function() {
  return goog.Uri.decodeOrEmpty_(this.toString());
};


/**
 * Invalidate the cache.
 * @private
 */
goog.Uri.QueryData.prototype.invalidateCache_ = function() {
  this.encodedQuery_ = null;
};


/**
 * Removes all keys that are not in the provided list. (Modifies this object.)
 * @param {Array<string>} keys The desired keys.
 * @return {!goog.Uri.QueryData} a reference to this object.
 */
goog.Uri.QueryData.prototype.filterKeys = function(keys) {
  this.ensureKeyMapInitialized_();
  this.keyMap_.forEach(
      function(value, key) {
        if (!goog.array.contains(keys, key)) {
          this.remove(key);
        }
      }, this);
  return this;
};


/**
 * Clone the query data instance.
 * @return {!goog.Uri.QueryData} New instance of the QueryData object.
 */
goog.Uri.QueryData.prototype.clone = function() {
  var rv = new goog.Uri.QueryData();
  rv.encodedQuery_ = this.encodedQuery_;
  if (this.keyMap_) {
    rv.keyMap_ = this.keyMap_.clone();
    rv.count_ = this.count_;
  }
  return rv;
};


/**
 * Helper function to get the key name from a JavaScript object. Converts
 * the object to a string, and to lower case if necessary.
 * @private
 * @param {*} arg The object to get a key name from.
 * @return {string} valid key name which can be looked up in #keyMap_.
 */
goog.Uri.QueryData.prototype.getKeyName_ = function(arg) {
  var keyName = String(arg);
  if (this.ignoreCase_) {
    keyName = keyName.toLowerCase();
  }
  return keyName;
};


/**
 * Ignore case in parameter names.
 * NOTE: If there are already key/value pairs in the QueryData, and
 * ignoreCase_ is set to false, the keys will all be lower-cased.
 * @param {boolean} ignoreCase whether this goog.Uri should ignore case.
 */
goog.Uri.QueryData.prototype.setIgnoreCase = function(ignoreCase) {
  var resetKeys = ignoreCase && !this.ignoreCase_;
  if (resetKeys) {
    this.ensureKeyMapInitialized_();
    this.invalidateCache_();
    this.keyMap_.forEach(
        function(value, key) {
          var lowerCase = key.toLowerCase();
          if (key != lowerCase) {
            this.remove(key);
            this.setValues(lowerCase, value);
          }
        }, this);
  }
  this.ignoreCase_ = ignoreCase;
};


/**
 * Extends a query data object with another query data or map like object. This
 * operates 'in-place', it does not create a new QueryData object.
 *
 * @param {...(goog.Uri.QueryData|goog.structs.Map<?, ?>|Object)} var_args
 *     The object from which key value pairs will be copied.
 */
goog.Uri.QueryData.prototype.extend = function(var_args) {
  for (var i = 0; i < arguments.length; i++) {
    var data = arguments[i];
    goog.structs.forEach(data,
        /** @this {goog.Uri.QueryData} */
        function(value, key) {
          this.add(key, value);
        }, this);
  }
};
