LCOV - code coverage report
Current view: directory - objdir/dist/include - nsStringBuffer.h (source / functions) Found Hit Coverage
Test: app.info Lines: 8 8 100.0 %
Date: 2012-06-02 Functions: 4 4 100.0 %

       1                 : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2                 : /* vim:set ts=2 sw=2 sts=2 et cindent: */
       3                 : /* ***** BEGIN LICENSE BLOCK *****
       4                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       5                 :  *
       6                 :  * The contents of this file are subject to the Mozilla Public License Version
       7                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       8                 :  * the License. You may obtain a copy of the License at
       9                 :  * http://www.mozilla.org/MPL/
      10                 :  *
      11                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      12                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      13                 :  * for the specific language governing rights and limitations under the
      14                 :  * License.
      15                 :  *
      16                 :  * The Original Code is Mozilla.
      17                 :  *
      18                 :  * The Initial Developer of the Original Code is IBM Corporation.
      19                 :  * Portions created by IBM Corporation are Copyright (C) 2003
      20                 :  * IBM Corporation. All Rights Reserved.
      21                 :  *
      22                 :  * Contributor(s):
      23                 :  *   Darin Fisher <darin@meer.net>
      24                 :  *
      25                 :  * Alternatively, the contents of this file may be used under the terms of
      26                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      27                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      28                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      29                 :  * of those above. If you wish to allow use of your version of this file only
      30                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      31                 :  * use your version of this file under the terms of the MPL, indicate your
      32                 :  * decision by deleting the provisions above and replace them with the notice
      33                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      34                 :  * the provisions above, a recipient may use your version of this file under
      35                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      36                 :  *
      37                 :  * ***** END LICENSE BLOCK ***** */
      38                 : 
      39                 : #ifndef nsStringBuffer_h__
      40                 : #define nsStringBuffer_h__
      41                 : 
      42                 : 
      43                 : /**
      44                 :  * This structure precedes the string buffers "we" allocate.  It may be the
      45                 :  * case that nsTAString::mData does not point to one of these special
      46                 :  * buffers.  The mFlags member variable distinguishes the buffer type.
      47                 :  *
      48                 :  * When this header is in use, it enables reference counting, and capacity
      49                 :  * tracking.  NOTE: A string buffer can be modified only if its reference
      50                 :  * count is 1.
      51                 :  */
      52                 : class nsStringBuffer
      53                 :   {
      54                 :     private:
      55                 :       friend class CheckStaticAtomSizes;
      56                 : 
      57                 :       PRInt32  mRefCount;
      58                 :       PRUint32 mStorageSize;
      59                 : 
      60                 :     public:
      61                 :       
      62                 :       /**
      63                 :        * Allocates a new string buffer, with given size in bytes and a
      64                 :        * reference count of one.  When the string buffer is no longer needed,
      65                 :        * it should be released via Release.
      66                 :        *
      67                 :        * It is up to the caller to set the bytes corresponding to the string
      68                 :        * buffer by calling the Data method to fetch the raw data pointer.  Care
      69                 :        * must be taken to properly null terminate the character array.  The
      70                 :        * storage size can be greater than the length of the actual string
      71                 :        * (i.e., it is not required that the null terminator appear in the last
      72                 :        * storage unit of the string buffer's data).
      73                 :        *
      74                 :        * @return new string buffer or null if out of memory.
      75                 :        */
      76                 :       static nsStringBuffer* Alloc(size_t storageSize);
      77                 : 
      78                 :       /**
      79                 :        * Resizes the given string buffer to the specified storage size.  This
      80                 :        * method must not be called on a readonly string buffer.  Use this API
      81                 :        * carefully!!
      82                 :        *
      83                 :        * This method behaves like the ANSI-C realloc function.  (i.e., If the
      84                 :        * allocation fails, null will be returned and the given string buffer
      85                 :        * will remain unmodified.)
      86                 :        *
      87                 :        * @see IsReadonly
      88                 :        */
      89                 :       static nsStringBuffer* Realloc(nsStringBuffer* buf, size_t storageSize);
      90                 : 
      91                 :       /**
      92                 :        * Increment the reference count on this string buffer.
      93                 :        */
      94                 :       void NS_FASTCALL AddRef();
      95                 : 
      96                 :       /**
      97                 :        * Decrement the reference count on this string buffer.  The string
      98                 :        * buffer will be destroyed when its reference count reaches zero.
      99                 :        */
     100                 :       void NS_FASTCALL Release();
     101                 : 
     102                 :       /**
     103                 :        * This method returns the string buffer corresponding to the given data
     104                 :        * pointer.  The data pointer must have been returned previously by a
     105                 :        * call to the nsStringBuffer::Data method.
     106                 :        */
     107        34056118 :       static nsStringBuffer* FromData(void* data)
     108                 :         {
     109        34056118 :           return reinterpret_cast<nsStringBuffer*> (data) - 1;
     110                 :         }
     111                 : 
     112                 :       /**
     113                 :        * This method returns the data pointer for this string buffer.
     114                 :        */
     115        24013960 :       void* Data() const
     116                 :         {
     117        24013960 :           return const_cast<char*> (reinterpret_cast<const char*> (this + 1));
     118                 :         }
     119                 : 
     120                 :       /**
     121                 :        * This function returns the storage size of a string buffer in bytes.
     122                 :        * This value is the same value that was originally passed to Alloc (or
     123                 :        * Realloc).
     124                 :        */
     125        11040777 :       PRUint32 StorageSize() const
     126                 :         {
     127        11040777 :           return mStorageSize;
     128                 :         }
     129                 : 
     130                 :       /**
     131                 :        * If this method returns false, then the caller can be sure that their
     132                 :        * reference to the string buffer is the only reference to the string
     133                 :        * buffer, and therefore it has exclusive access to the string buffer and
     134                 :        * associated data.  However, if this function returns true, then other
     135                 :        * consumers may rely on the data in this buffer being immutable and
     136                 :        * other threads may access this buffer simultaneously.
     137                 :        */
     138         7182668 :       bool IsReadonly() const
     139                 :         {
     140         7182668 :           return mRefCount > 1;
     141                 :         }
     142                 : 
     143                 :       /**
     144                 :        * The FromString methods return a string buffer for the given string 
     145                 :        * object or null if the string object does not have a string buffer.
     146                 :        * The reference count of the string buffer is NOT incremented by these
     147                 :        * methods.  If the caller wishes to hold onto the returned value, then
     148                 :        * the returned string buffer must have its reference count incremented
     149                 :        * via a call to the AddRef method.
     150                 :        */
     151                 :       static nsStringBuffer* FromString(const nsAString &str);
     152                 :       static nsStringBuffer* FromString(const nsACString &str);
     153                 : 
     154                 :       /**
     155                 :        * The ToString methods assign this string buffer to a given string
     156                 :        * object.  If the string object does not support sharable string
     157                 :        * buffers, then its value will be set to a copy of the given string
     158                 :        * buffer.  Otherwise, these methods increment the reference count of the
     159                 :        * given string buffer.  It is important to specify the length (in
     160                 :        * storage units) of the string contained in the string buffer since the
     161                 :        * length of the string may be less than its storage size.  The string
     162                 :        * must have a null terminator at the offset specified by |len|.
     163                 :        *
     164                 :        * NOTE: storage size is measured in bytes even for wide strings;
     165                 :        *       however, string length is always measured in storage units
     166                 :        *       (2-byte units for wide strings).
     167                 :        */
     168                 :       void ToString(PRUint32 len, nsAString &str,
     169                 :                            bool aMoveOwnership = false);
     170                 :       void ToString(PRUint32 len, nsACString &str,
     171                 :                            bool aMoveOwnership = false);
     172                 : 
     173                 :       /**
     174                 :        * This measures the size.  It should only be used if the StringBuffer is
     175                 :        * unshared.  This is checked.
     176                 :        */
     177                 :       size_t SizeOfIncludingThisMustBeUnshared(nsMallocSizeOfFun aMallocSizeOf) const;
     178                 : 
     179                 :       /**
     180                 :        * This measures the size only if the StringBuffer is unshared.
     181                 :        */
     182                 :       size_t SizeOfIncludingThisIfUnshared(nsMallocSizeOfFun aMallocSizeOf) const;
     183                 :   };
     184                 : 
     185                 : #endif /* !defined(nsStringBuffer_h__ */

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