src/windows/ctemplate/template_dictionary.h

// Copyright (c) 2006, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// ---
// Author: csilvers@google.com (Craig Silverstein)
//
// Based on the 'old' TemplateDictionary by Frank Jernigan.
//
// A template dictionary maps names (as found in template files)
// to their values.  There are three types of names:
//   variables: value is a string.
//   sections: value is a list of sub-dicts to use when expanding the section;
//             the section is expanded once per sub-dict.
//   template-include: value is a list of pairs: name of the template file
//             to include, and the sub-dict to use when expanding it.
// TemplateDictionary has routines for setting these values.
//
// For (many) more details, see the doc/ directory.

#ifndef TEMPLATE_TEMPLATE_DICTIONARY_H_
#define TEMPLATE_TEMPLATE_DICTIONARY_H_

#include <stdarg.h>      // for StringAppendV()
#include <stddef.h>      // for size_t and ptrdiff_t
#include <stdlib.h>      // for NULL
#include <sys/types.h>
#include <functional>    // for less<>
#include <map>
#include <string>
#include <vector>

#include <ctemplate/str_ref.h>
#include <ctemplate/template_dictionary_interface.h>
#include <ctemplate/template_modifiers.h>
#include <ctemplate/template_string.h>

// NOTE: if you are statically linking the template library into your binary
// (rather than using the template .dll), set '/D CTEMPLATE_DLL_DECL='
// as a compiler flag in your project file to turn off the dllimports.
#ifndef CTEMPLATE_DLL_DECL
# define CTEMPLATE_DLL_DECL  __declspec(dllimport)
#endif

namespace ctemplate {
template <class T, class C> class ArenaAllocator;
class UnsafeArena;
template<typename A, int B, typename C, typename D> class small_map;
template<typename NormalMap> class small_map_default_init;  // in small_map.h
}

namespace ctemplate {


class CTEMPLATE_DLL_DECL TemplateDictionary : public TemplateDictionaryInterface {
 public:
  // name is used only for debugging.
  // arena is used to store all names and values.  It can be NULL (the
  //    default), in which case we create own own arena.
  explicit TemplateDictionary(const TemplateString& name,
                              UnsafeArena* arena=NULL);
  ~TemplateDictionary();

  // If you want to be explicit, you can use NO_ARENA as a synonym to NULL.
  static UnsafeArena* const NO_ARENA;

  std::string name() const {
    return std::string(name_.data(), name_.size());
  }

  // Returns a recursive copy of this dictionary.  This dictionary
  // *must* be a "top-level" dictionary (that is, not created via
  // AddSectionDictionary() or AddIncludeDictionary()).  Caller owns
  // the resulting dict, and must delete it.  If arena is NULL, we
  // create our own.  Returns NULL if the copy fails (probably because
  // the "top-level" rule was violated).
  TemplateDictionary* MakeCopy(const TemplateString& name_of_copy,
                               UnsafeArena* arena=NULL);

  // --- Routines for VARIABLES
  // These are the five main routines used to set the value of a variable.
  // As always, wherever you see TemplateString, you can also pass in
  // either a char* or a C++ string, or a TemplateString(s, slen).

  void SetValue(const TemplateString variable, const TemplateString value);
  void SetIntValue(const TemplateString variable, long value);
  void SetFormattedValue(const TemplateString variable, const char* format, ...)
#if 0
      __attribute__((__format__ (__printf__, 3, 4)))
#endif
     ;  // starts at 3 because of implicit 1st arg 'this'

  class SetProxy {
  public:
    SetProxy(TemplateDictionary& dict, const TemplateString& variable) :
      dict_(dict),
      variable_(variable) {
    }

    void operator=(str_ref value) {
      dict_.SetValue(variable_, TemplateString(value.data(), value.size()));
    }

    void operator=(long value) {
      dict_.SetIntValue(variable_, value);
    }

  private:
    TemplateDictionary& dict_;
    const TemplateString& variable_;
  };

  SetProxy operator[](const TemplateString& variable) {
    return SetProxy(*this, variable);
  }

  // We also let you set values in the 'global' dictionary which is
  // referenced when all other dictionaries fail.  Note this is a
  // static method: no TemplateDictionary instance needed.  Since
  // this routine is rarely used, we don't provide variants.
  static void SetGlobalValue(const TemplateString variable,
                             const TemplateString value);

  // This is used for a value that you want to be 'global', but only
  // in the scope of a given template, including all its sections and
  // all its sub-included dictionaries.  The main difference between
  // SetTemplateGlobalValue() and SetValue(), is that
  // SetTemplateGlobalValue() values persist across template-includes.
  // This is intended for session-global data; since that should be
  // fairly rare, we don't provide variants.
  void SetTemplateGlobalValue(const TemplateString variable,
                              const TemplateString value);

  // Similar SetTemplateGlobalValue above, this method shows a section in this
  // template, all its sections, and all its template-includes. This is intended
  // for session-global data, for example allowing you to show variant portions
  // of your template for certain browsers/languages without having to call
  // ShowSection on each template you use.
  void ShowTemplateGlobalSection(const TemplateString variable);

  // These routines are like SetValue and SetTemplateGlobalValue, but
  // they do not make a copy of the input data. THE CALLER IS
  // RESPONSIBLE FOR ENSURING THE PASSED-IN STRINGS LIVE FOR AT LEAST
  // AS LONG AS THIS DICTIONARY! In general, they yield a quite minor
  // performance increase for significant increased code fragility,
  // so do not use them unless you really need the speed improvements.
  void SetValueWithoutCopy(const TemplateString variable,
                           const TemplateString value);
  void SetTemplateGlobalValueWithoutCopy(const TemplateString variable,
                                         const TemplateString value);


  // --- Routines for SECTIONS
  // We show a section once per dictionary that is added with its name.
  // Recall that lookups are hierarchical: if a section tried to look
  // up a variable in its sub-dictionary and fails, it will look next
  // in its parent dictionary (us).  So it's perfectly appropriate to
  // keep the sub-dictionary empty: that will show the section once,
  // and take all var definitions from us.  ShowSection() is a
  // convenience routine that does exactly that.

  // Creates an empty dictionary whose parent is us, and returns it.
  // As always, wherever you see TemplateString, you can also pass in
  // either a char* or a C++ string, or a TemplateString(s, slen).
  TemplateDictionary* AddSectionDictionary(const TemplateString section_name);
  void ShowSection(const TemplateString section_name);

  // A convenience method.  Often a single variable is surrounded by
  // some HTML that should not be printed if the variable has no
  // value.  The way to do this is to put that html in a section.
  // This method makes it so the section is shown exactly once, with a
  // dictionary that maps the variable to the proper value.  If the
  // value is "", on the other hand, this method does nothing, so the
  // section remains hidden.
  void SetValueAndShowSection(const TemplateString variable,
                              const TemplateString value,
                              const TemplateString section_name);


  // --- Routines for TEMPLATE-INCLUDES
  // Included templates are treated like sections, but they require
  // the name of the include-file to go along with each dictionary.

  TemplateDictionary* AddIncludeDictionary(const TemplateString variable);

  // This is required for include-templates; it specifies what template
  // to include.  But feel free to call this on any dictionary, to
  // document what template-file the dictionary is intended to go with.
  void SetFilename(const TemplateString filename);

  // --- DEBUGGING TOOLS

  // Logs the contents of a dictionary and its sub-dictionaries.
  // Dump goes to stdout/stderr, while DumpToString goes to the given string.
  // 'indent' is how much to indent each line of the output.
  void Dump(int indent=0) const;
  virtual void DumpToString(std::string* out, int indent=0) const;


  // --- DEPRECATED ESCAPING FUNCTIONALITY

  // Escaping in the binary has been deprecated in favor of using modifiers
  // to do the escaping in the template:
  //            "...{{MYVAR:html_escape}}..."
  void SetEscapedValue(const TemplateString variable, const TemplateString value,
                       const TemplateModifier& escfn);
  void SetEscapedFormattedValue(const TemplateString variable,
                                const TemplateModifier& escfn,
                                const char* format, ...)
#if 0
      __attribute__((__format__ (__printf__, 4, 5)))
#endif
     ;  // starts at 4 because of implicit 1st arg 'this'
  void SetEscapedValueAndShowSection(const TemplateString variable,
                                     const TemplateString value,
                                     const TemplateModifier& escfn,
                                     const TemplateString section_name);


 private:
  friend class SectionTemplateNode;   // for access to GetSectionValue(), etc.
  friend class TemplateTemplateNode;  // for access to GetSectionValue(), etc.
  friend class VariableTemplateNode;  // for access to GetSectionValue(), etc.
  // For unittesting code using a TemplateDictionary.
  friend class TemplateDictionaryPeer;

  class DictionaryPrinter;  // nested class
  friend class DictionaryPrinter;

  // We need this functor to tell small_map how to create a map<> when
  // it decides to do so: we want it to create that map on the arena.
  class map_arena_init;

  typedef std::vector<TemplateDictionary*,
                      ArenaAllocator<TemplateDictionary*, UnsafeArena> >
      DictVector;
  // The '4' here is the size where small_map switches from vector<> to map<>.
  typedef small_map<std::map<TemplateId, TemplateString, std::less<TemplateId>,
                     ArenaAllocator<std::pair<const TemplateId, TemplateString>,
                                    UnsafeArena> >,
                    4, std::equal_to<TemplateId>, map_arena_init>
      VariableDict;
  typedef small_map<std::map<TemplateId, DictVector*, std::less<TemplateId>,
                     ArenaAllocator<std::pair<const TemplateId, DictVector*>,
                                    UnsafeArena> >,
                    4, std::equal_to<TemplateId>, map_arena_init>
      SectionDict;
  typedef small_map<std::map<TemplateId, DictVector*, std::less<TemplateId>,
                    ArenaAllocator<std::pair<const TemplateId, DictVector*>,
                                   UnsafeArena> >,
                    4, std::equal_to<TemplateId>, map_arena_init>
      IncludeDict;
  // This is used only for global_dict_, which is just like a VariableDict
  // but does not bother with an arena (since this memory lives forever).
  typedef small_map<std::map<TemplateId, TemplateString, std::less<TemplateId> >,
                    4, std::equal_to<TemplateId>,
                    small_map_default_init<
                       std::map<TemplateId, TemplateString,
                                std::less<TemplateId> > > >
      GlobalDict;


  // These are helper functions to allocate the parts of the dictionary
  // on the arena.
  template<typename T> inline void LazilyCreateDict(T** dict);
  inline void LazyCreateTemplateGlobalDict();
  inline DictVector* CreateDictVector();
  inline TemplateDictionary* CreateTemplateSubdict(
      const TemplateString& name,
      UnsafeArena* arena,
      TemplateDictionary* parent_dict,
      TemplateDictionary* template_global_dict_owner);

  // This is a helper function to insert <key,value> into m.
  // Normally, we'd just use m[key] = value, but map rules
  // require default constructor to be public for that to compile, and
  // for some types we'd rather not allow that.  HashInsert also inserts
  // the key into an id(key)->key map, to allow for id-lookups later.
  template<typename MapType, typename ValueType>
  static void HashInsert(MapType* m, TemplateString key, ValueType value);

  // Constructor created for all children dictionaries. This includes
  // both a pointer to the parent dictionary and also the the
  // template-global dictionary from which all children (both
  // IncludeDictionary and SectionDictionary) inherit.  Values are
  // filled into global_template_dict via SetTemplateGlobalValue.
  explicit TemplateDictionary(const TemplateString& name,
                              class UnsafeArena* arena,
                              TemplateDictionary* parent_dict,
                              TemplateDictionary* template_global_dict_owner);

  // Helps set up the static stuff. Must be called exactly once before
  // accessing global_dict_.  GoogleOnceInit() is used to manage that
  // initialization in a thread-safe way.
  static void SetupGlobalDict();

  // Utility functions for copying a string into the arena.
  // Memdup also copies in a trailing NUL, which is why we have the
  // trailing-NUL check in the TemplateString version of Memdup.
  TemplateString Memdup(const char* s, size_t slen);
  TemplateString Memdup(const TemplateString& s) {
    if (s.is_immutable() && s.data()[s.size()] == '\0') {
      return s;
    }
    return Memdup(s.data(), s.size());
  }

  // Used for recursive MakeCopy calls.
  TemplateDictionary* InternalMakeCopy(
      const TemplateString& name_of_copy,
      UnsafeArena* arena,
      TemplateDictionary* parent_dict,
      TemplateDictionary* template_global_dict_owner);

  // A helper for creating section and include dicts.
  static std::string CreateSubdictName(
      const TemplateString& dict_name, const TemplateString& sub_name,
      size_t index, const char* suffix);

  // Must be called whenever we add a value to one of the dictionaries above,
  // to ensure that we can reconstruct the id -> string mapping.
  static void AddToIdToNameMap(TemplateId id, const TemplateString& str);

  // Used to do the formatting for the SetFormatted*() functions
  static int StringAppendV(char* space, char** out,
                           const char* format, va_list ap);

  // How Template::Expand() and its children access the template-dictionary.
  // These fill the API required by TemplateDictionaryInterface.
  virtual TemplateString GetValue(const TemplateString& variable) const;
  virtual bool IsHiddenSection(const TemplateString& name) const;
  virtual bool IsUnhiddenSection(const TemplateString& name) const {
    return !IsHiddenSection(name);
  }
  virtual bool IsHiddenTemplate(const TemplateString& name) const;
  virtual const char* GetIncludeTemplateName(
      const TemplateString& variable, int dictnum) const;

  // Determine whether there's anything set in this dictionary
  bool Empty() const;

  // This is needed by DictionaryPrinter because it's not a friend
  // of TemplateString, but we are
  static std::string PrintableTemplateString(
      const TemplateString& ts) {
    return std::string(ts.data(), ts.size());
  }
  static bool InvalidTemplateString(const TemplateString& ts) {
    return ts.data() == NULL;
  }
  // Compilers differ about whether nested classes inherit our friendship.
  // The only thing DictionaryPrinter needs is IdToString, so just re-export.
  static TemplateString IdToString(TemplateId id) {   // for DictionaryPrinter
    return TemplateString::IdToString(id);
  }

  // CreateTemplateIterator
  //   This is SectionIterator exactly, just with a different name to
  //   self-document the fact the value applies to a template include.
  // Caller frees return value.
  virtual TemplateDictionaryInterface::Iterator* CreateTemplateIterator(
      const TemplateString& section_name) const;

  // CreateSectionIterator
  //   Factory method implementation that constructs a iterator representing the
  //   set of dictionaries associated with a section name, if any. This
  //   implementation checks the local dictionary itself, not the template-wide
  //   dictionary or the global dictionary.
  // Caller frees return value.
  virtual TemplateDictionaryInterface::Iterator* CreateSectionIterator(
      const TemplateString& section_name) const;

  // TemplateDictionary-specific implementation of dictionary iterators.
  template <typename T>   // T is *TemplateDictionary::const_iterator
  class Iterator : public TemplateDictionaryInterface::Iterator {
   protected:
    friend class TemplateDictionary;
    Iterator(T begin, T end) : begin_(begin), end_(end) { }
   public:
    virtual ~Iterator() { }
    virtual bool HasNext() const;
    virtual const TemplateDictionaryInterface& Next();
   private:
    T begin_;
    const T end_;
  };

  // A small helper factory function for Iterator
  template <typename T>
  static Iterator<typename T::const_iterator>* MakeIterator(const T& dv) {
    return new Iterator<typename T::const_iterator>(dv.begin(), dv.end());
  }


  // The "name" of the dictionary for debugging output (Dump, etc.)
  // The arena, also set at construction time.
  class UnsafeArena* const arena_;
  bool should_delete_arena_;   // only true if we 'new arena' in constructor
  TemplateString name_;        // points into the arena, or to static memory

  // The three dictionaries that I own -- for vars, sections, and template-incs
  VariableDict* variable_dict_;
  SectionDict* section_dict_;
  IncludeDict* include_dict_;


  // The template_global_dict is consulted if a lookup in the variable, section,
  // or include dicts named above fails. It forms a convenient place to store
  // session-specific data that's applicable to all templates in the dictionary
  // tree.
  // For the parent-template, template_global_dict_ is not NULL, and
  // template_global_dict_owner_ is this.  For all of its children,
  // template_global_dict_ is NULL, and template_global_dict_owner_ points to
  // the root parent-template (the one with the non-NULL template_global_dict_).
  TemplateDictionary* template_global_dict_;
  TemplateDictionary* template_global_dict_owner_;

  // My parent dictionary, used when variable lookups at this level fail.
  // Note this is only for *variables* and *sections*, not templates.
  TemplateDictionary* parent_dict_;
  // The static, global dictionary, at the top of the parent-dictionary chain
  static GlobalDict* global_dict_;
  static TemplateString* empty_string_;  // what is returned on lookup misses

  // The filename associated with this dictionary.  If set, this declares
  // what template the dictionary is supposed to be expanded with.  Required
  // for template-includes, optional (but useful) for 'normal' dicts.
  const char* filename_;

 private:
  // Can't invoke copy constructor or assignment operator
  TemplateDictionary(const TemplateDictionary&);
  void operator=(const TemplateDictionary&);
};

}


#endif  // TEMPLATE_TEMPLATE_DICTIONARY_H_