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      1 /*
      2  * libjingle
      3  * Copyright 2010, Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #ifndef TALK_P2P_BASE_PARSING_H_
     29 #define TALK_P2P_BASE_PARSING_H_
     30 
     31 #include <string>
     32 #include <vector>
     33 #include "talk/base/basictypes.h"
     34 #include "talk/base/stringencode.h"
     35 #include "talk/xmllite/xmlelement.h"  // Needed to delete ParseError.extra.
     36 
     37 namespace cricket {
     38 
     39 typedef std::vector<buzz::XmlElement*> XmlElements;
     40 
     41 // We decided "bool Parse(in, out*, error*)" is generally the best
     42 // parse signature.  "out Parse(in)" doesn't allow for errors.
     43 // "error* Parse(in, out*)" doesn't allow flexible memory management.
     44 
     45 // The error type for parsing.
     46 struct ParseError {
     47  public:
     48   // explains the error
     49   std::string text;
     50   // provide details about what wasn't parsable
     51   const buzz::XmlElement* extra;
     52 
     53   ParseError() : extra(NULL) {}
     54 
     55   ~ParseError() {
     56     delete extra;
     57   }
     58 
     59   void SetText(const std::string& text) {
     60     this->text = text;
     61   }
     62 };
     63 
     64 // The error type for writing.
     65 struct WriteError {
     66   std::string text;
     67 
     68   void SetText(const std::string& text) {
     69     this->text = text;
     70   }
     71 };
     72 
     73 // Convenience method for returning a message when parsing fails.
     74 bool BadParse(const std::string& text, ParseError* err);
     75 
     76 // Convenience method for returning a message when writing fails.
     77 bool BadWrite(const std::string& text, WriteError* error);
     78 
     79 // helper XML functions
     80 std::string GetXmlAttr(const buzz::XmlElement* elem,
     81                        const buzz::QName& name,
     82                        const std::string& def);
     83 std::string GetXmlAttr(const buzz::XmlElement* elem,
     84                        const buzz::QName& name,
     85                        const char* def);
     86 // Return true if the value is "true" or "1".
     87 bool GetXmlAttr(const buzz::XmlElement* elem,
     88                 const buzz::QName& name, bool def);
     89 int GetXmlAttr(const buzz::XmlElement* elem,
     90                const buzz::QName& name, int def);
     91 
     92 template <class T>
     93 bool GetXmlAttr(const buzz::XmlElement* elem,
     94                 const buzz::QName& name,
     95                 T* val_out) {
     96   if (!elem->HasAttr(name)) {
     97     return false;
     98   }
     99   std::string unparsed = elem->Attr(name);
    100   return talk_base::FromString(unparsed, val_out);
    101 }
    102 
    103 template <class T>
    104 bool GetXmlAttr(const buzz::XmlElement* elem,
    105                 const buzz::QName& name,
    106                 const T& def,
    107                 T* val_out) {
    108   if (!elem->HasAttr(name)) {
    109     *val_out = def;
    110     return true;
    111   }
    112   return GetXmlAttr(elem, name, val_out);
    113 }
    114 
    115 template <class T>
    116 bool AddXmlAttr(buzz::XmlElement* elem,
    117                 const buzz::QName& name, const T& val) {
    118   std::string buf;
    119   if (!talk_base::ToString(val, &buf)) {
    120     return false;
    121   }
    122   elem->AddAttr(name, buf);
    123   return true;
    124 }
    125 
    126 template <class T>
    127 bool SetXmlBody(buzz::XmlElement* elem, const T& val) {
    128   std::string buf;
    129   if (!talk_base::ToString(val, &buf)) {
    130     return false;
    131   }
    132   elem->SetBodyText(buf);
    133   return true;
    134 }
    135 
    136 const buzz::XmlElement* GetXmlChild(const buzz::XmlElement* parent,
    137                                     const std::string& name);
    138 
    139 bool RequireXmlChild(const buzz::XmlElement* parent,
    140                      const std::string& name,
    141                      const buzz::XmlElement** child,
    142                      ParseError* error);
    143 bool RequireXmlAttr(const buzz::XmlElement* elem,
    144                     const buzz::QName& name,
    145                     std::string* value,
    146                     ParseError* error);
    147 void AddXmlAttrIfNonEmpty(buzz::XmlElement* elem,
    148                           const buzz::QName name,
    149                           const std::string& value);
    150 void AddXmlChildren(buzz::XmlElement* parent,
    151                     const std::vector<buzz::XmlElement*>& children);
    152 void CopyXmlChildren(const buzz::XmlElement* source, buzz::XmlElement* dest);
    153 std::vector<buzz::XmlElement*> CopyOfXmlChildren(const buzz::XmlElement* elem);
    154 
    155 }  // namespace cricket
    156 
    157 #endif  // TALK_P2P_BASE_PARSING_H_
    158