Line data    Source code

       1             : /* This Source Code Form is subject to the terms of the Mozilla Public
       2             :  * License, v. 2.0. If a copy of the MPL was not distributed with this
       3             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       4             : 
       5             : #ifndef nsHtml5String_h
       6             : #define nsHtml5String_h
       7             : 
       8             : #include "nsString.h"
       9             : 
      10             : class nsHtml5TreeBuilder;
      11             : 
      12             : /**
      13             :  * A pass-by-value type that combines an unsafe `nsStringBuffer*` with its
      14             :  * logical length (`uint32_t`). (`nsStringBuffer` knows its capacity but not
      15             :  * its logical length, i.e. how much of the capacity is in use.)
      16             :  *
      17             :  * Holding or passing this type is as unsafe as holding or passing
      18             :  * `nsStringBuffer*`.
      19             :  *
      20             :  * Empty strings and null strings are distinct. Since an empty nsString does
      21             :  * not have a an `nsStringBuffer`, both empty and null `nsHtml5String` have
      22             :  * `nullptr` as `mBuffer`. If `mBuffer` is `nullptr`, the empty case is marked
      23             :  * with `mLength` being zero and the null case with `mLength` being non-zero.
      24             :  */
      25             : class nsHtml5String final
      26             : {
      27             : public:
      28             :   /**
      29             :    * Default constructor.
      30             :    */
      31           8 :   inline nsHtml5String()
      32           8 :     : nsHtml5String(nullptr)
      33             :   {
      34           8 :   }
      35             : 
      36             :   /**
      37             :    * Constructor from nullptr.
      38             :    */
      39          47 :   inline MOZ_IMPLICIT nsHtml5String(decltype(nullptr))
      40          47 :     : mBuffer(nullptr)
      41          47 :     , mLength(UINT32_MAX)
      42             :   {
      43          47 :   }
      44             : 
      45          59 :   inline uint32_t Length() const { return mBuffer ? mLength : 0; }
      46             : 
      47             :   /**
      48             :    * False iff the string is logically null
      49             :    */
      50          37 :   inline MOZ_IMPLICIT operator bool() const { return !(!mBuffer && mLength); }
      51             : 
      52             :   void ToString(nsAString& aString);
      53             : 
      54             :   void CopyToBuffer(char16_t* aBuffer);
      55             : 
      56             :   bool LowerCaseEqualsASCII(const char* aLowerCaseLiteral);
      57             : 
      58             :   bool EqualsASCII(const char* aLiteral);
      59             : 
      60             :   bool LowerCaseStartsWithASCII(const char* aLowerCaseLiteral);
      61             : 
      62             :   bool Equals(nsHtml5String aOther);
      63             : 
      64             :   nsHtml5String Clone();
      65             : 
      66             :   void Release();
      67             : 
      68             :   static nsHtml5String FromBuffer(char16_t* aBuffer,
      69             :                                   int32_t aLength,
      70             :                                   nsHtml5TreeBuilder* aTreeBuilder);
      71             : 
      72             :   static nsHtml5String FromLiteral(const char* aLiteral);
      73             : 
      74             :   static nsHtml5String FromString(const nsAString& aString);
      75             : 
      76             :   static nsHtml5String EmptyString();
      77             : 
      78             : private:
      79             :   /**
      80             :    * Constructor from raw parts.
      81             :    */
      82             :   nsHtml5String(already_AddRefed<nsStringBuffer> aBuffer, uint32_t aLength);
      83             : 
      84             :   /**
      85             :    * nullptr if the string is logically null or logically empty
      86             :    */
      87             :   nsStringBuffer* mBuffer;
      88             : 
      89             :   /**
      90             :    * The length of the string. non-zero if the string is logically null.
      91             :    */
      92             :   uint32_t mLength;
      93             : };
      94             : 
      95             : #endif // nsHtml5String_h