X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/b5dbe15d0bacde245539f54c4d97af6b4696f01f..a7689c49fe02c0c065facf736ab28b19f5997b7c:/include/wx/buffer.h

diff --git a/include/wx/buffer.h b/include/wx/buffer.h
index 3d7d6403f6..951777a13c 100644
--- a/include/wx/buffer.h
+++ b/include/wx/buffer.h
@@ -24,139 +24,337 @@ class WXDLLIMPEXP_FWD_BASE wxCStrData;
 // of new/delete
 // ----------------------------------------------------------------------------
 
+// helpers used by wxCharTypeBuffer
+namespace wxPrivate
+{
+
+struct UntypedBufferData
+{
+    enum Kind
+    {
+        Owned,
+        NonOwned
+    };
+
+    UntypedBufferData(void *str, size_t len, Kind kind = Owned)
+        : m_str(str), m_length(len), m_ref(1), m_owned(kind == Owned) {}
+
+    ~UntypedBufferData()
+    {
+        if ( m_owned )
+            free(m_str);
+    }
+
+    void *m_str;
+    size_t m_length;
+
+    // "short" to have sizeof(Data)=12 on 32bit archs
+    unsigned short m_ref;
+
+    bool m_owned;
+};
+
+// NB: this is defined in string.cpp and not the (non-existent) buffer.cpp
+WXDLLIMPEXP_BASE UntypedBufferData * GetUntypedNullData();
+
+} // namespace wxPrivate
+
+
+// Reference-counted character buffer for storing string data. The buffer
+// is only valid for as long as the "parent" object that provided the data
+// is valid; see wxCharTypeBuffer<T> for persistent variant.
 template <typename T>
-class wxCharTypeBuffer
+class wxScopedCharTypeBuffer
 {
 public:
     typedef T CharType;
 
-    wxCharTypeBuffer(const CharType *str = NULL)
-        : m_str(str ? wxStrdup(str) : NULL),
-          m_owned(true)
+    wxScopedCharTypeBuffer()
     {
+        m_data = GetNullData();
     }
 
-    wxCharTypeBuffer(size_t len)
-        : m_str((CharType *)malloc((len + 1)*sizeof(CharType))),
-          m_owned(true)
+    // Creates "non-owned" buffer, i.e. 'str' is not owned by the buffer
+    // and doesn't get freed by dtor. Used e.g. to point to wxString's internal
+    // storage.
+    static
+    const wxScopedCharTypeBuffer CreateNonOwned(const CharType *str,
+                                                size_t len = wxNO_LEN)
     {
-        m_str[len] = (CharType)0;
+        if ( len == wxNO_LEN )
+            len = wxStrlen(str);
+
+        wxScopedCharTypeBuffer buf;
+        if ( str )
+            buf.m_data = new Data(const_cast<CharType*>(str), len, Data::NonOwned);
+        return buf;
     }
 
-    static const wxCharTypeBuffer CreateNonOwned(const CharType *str)
+    // Creates "owned" buffer, i.e. takes over ownership of 'str' and frees it
+    // in dtor (if ref.count reaches 0).
+    static
+    const wxScopedCharTypeBuffer CreateOwned(CharType *str,
+                                             size_t len = wxNO_LEN )
     {
-        wxCharTypeBuffer buf;
-        buf.m_str = wx_const_cast(CharType*, str);
-        buf.m_owned = false;
+        if ( len == wxNO_LEN )
+            len = wxStrlen(str);
+
+        wxScopedCharTypeBuffer buf;
+        if ( str )
+            buf.m_data = new Data(str, len);
         return buf;
     }
 
-    /* no need to check for NULL, free() does it */
-    ~wxCharTypeBuffer()
+    wxScopedCharTypeBuffer(const wxScopedCharTypeBuffer& src)
     {
-        if ( m_owned)
-            free(m_str);
+        m_data = src.m_data;
+        IncRef();
     }
 
-    /*
-        WARNING:
+    wxScopedCharTypeBuffer& operator=(const wxScopedCharTypeBuffer& src)
+    {
+        if ( &src == this )
+            return *this;
 
-        the copy ctor and assignment operators change the passed in object
-        even although it is declared as "const", so:
+        DecRef();
+        m_data = src.m_data;
+        IncRef();
 
-        a) it shouldn't be really const
-        b) you shouldn't use it afterwards (or know that it was reset)
+        return *this;
+    }
 
-        This is very ugly but is unfortunately needed to make the normal use
-        of wxCharTypeBuffer buffer objects possible and is very similar to what
-        std::auto_ptr<> does (as if it were an excuse...)
-    */
+    ~wxScopedCharTypeBuffer()
+    {
+        DecRef();
+    }
 
-    /*
-       because of the remark above, release() is declared const even if it
-       isn't really const
-     */
+    // NB: this method is only const for backward compatibility. It used to
+    //     be needed for auto_ptr-like semantics of the copy ctor, but now
+    //     that ref-counting is used, it's not really needed.
     CharType *release() const
     {
-        wxASSERT_MSG( m_owned, _T("can't release non-owned buffer") );
-        return DoRelease();
+        if ( m_data == GetNullData() )
+            return NULL;
+
+        wxASSERT_MSG( m_data->m_owned, wxT("can't release non-owned buffer") );
+        wxASSERT_MSG( m_data->m_ref == 1, wxT("can't release shared buffer") );
+
+        CharType * const p = m_data->Get();
+
+        wxScopedCharTypeBuffer *self = const_cast<wxScopedCharTypeBuffer*>(this);
+        self->m_data->Set(NULL, 0);
+        self->DecRef();
+
+        return p;
     }
 
     void reset()
     {
-        if ( m_owned )
-            free(m_str);
-        m_str = NULL;
+        DecRef();
     }
 
-    wxCharTypeBuffer(const wxCharTypeBuffer& src)
+    CharType *data() { return m_data->Get(); }
+    const CharType *data() const { return  m_data->Get(); }
+    operator const CharType *() const { return data(); }
+    CharType operator[](size_t n) const { return data()[n]; }
+
+    size_t length() const { return m_data->m_length; }
+
+protected:
+    // reference-counted data
+    struct Data : public wxPrivate::UntypedBufferData
+    {
+        Data(CharType *str, size_t len, Kind kind = Owned)
+            : wxPrivate::UntypedBufferData(str, len, kind)
+        {
+        }
+
+        CharType *Get() const { return static_cast<CharType *>(m_str); }
+        void Set(CharType *str, size_t len)
+        {
+            m_str = str;
+            m_length = len;
+        }
+    };
+
+    // placeholder for NULL string, to simplify this code
+    static Data *GetNullData()
+    {
+        return static_cast<Data *>(wxPrivate::GetUntypedNullData());
+    }
+
+    void IncRef()
+    {
+        if ( m_data == GetNullData() ) // exception, not ref-counted
+            return;
+        m_data->m_ref++;
+    }
+
+    void DecRef()
     {
-        CopyFrom(src);
+        if ( m_data == GetNullData() ) // exception, not ref-counted
+            return;
+        if ( --m_data->m_ref == 0 )
+            delete m_data;
+        m_data = GetNullData();
     }
 
+    // sets this object to a be copy of 'other'; if 'src' is non-owned,
+    // a deep copy is made and 'this' will contain new instance of the data
+    void MakeOwnedCopyOf(const wxScopedCharTypeBuffer& src)
+    {
+        this->DecRef();
+
+        if ( src.m_data == this->GetNullData() )
+        {
+            this->m_data = this->GetNullData();
+        }
+        else if ( src.m_data->m_owned )
+        {
+            this->m_data = src.m_data;
+            this->IncRef();
+        }
+        else
+        {
+            // if the scoped buffer had non-owned data, we have to make
+            // a copy here, because src.m_data->m_str is valid only for as long
+            // as 'src' exists
+            this->m_data = new Data
+                               (
+                                   StrCopy(src.data(), src.length()),
+                                   src.length()
+                               );
+        }
+    }
+
+    static CharType *StrCopy(const CharType *src, size_t len)
+    {
+        CharType *dst = (CharType*)malloc(sizeof(CharType) * (len + 1));
+        if ( dst )
+            memcpy(dst, src, sizeof(CharType) * (len + 1));
+        return dst;
+    }
+
+protected:
+    Data *m_data;
+};
+
+typedef wxScopedCharTypeBuffer<char> wxScopedCharBuffer;
+typedef wxScopedCharTypeBuffer<wchar_t> wxScopedWCharBuffer;
+
+
+// this buffer class always stores data in "owned" (persistent) manner
+template <typename T>
+class wxCharTypeBuffer : public wxScopedCharTypeBuffer<T>
+{
+protected:
+    typedef typename wxScopedCharTypeBuffer<T>::Data Data;
+
+public:
+    typedef T CharType;
+
+    wxCharTypeBuffer(const CharType *str = NULL, size_t len = wxNO_LEN)
+    {
+        if ( str )
+        {
+            if ( len == wxNO_LEN )
+                len = wxStrlen(str);
+            this->m_data = new Data(this->StrCopy(str, len), len);
+        }
+        else
+        {
+            this->m_data = this->GetNullData();
+        }
+    }
+
+    wxCharTypeBuffer(size_t len)
+    {
+        this->m_data =
+            new Data((CharType *)malloc((len + 1)*sizeof(CharType)), len);
+        this->m_data->Get()[len] = (CharType)0;
+    }
+
+    wxCharTypeBuffer(const wxCharTypeBuffer& src)
+        : wxScopedCharTypeBuffer<T>(src) {}
+
     wxCharTypeBuffer& operator=(const CharType *str)
     {
-        if ( m_owned )
-            free(m_str);
-        m_str = str ? wxStrdup(str) : NULL;
-        m_owned = true;
+        this->DecRef();
+
+        if ( str )
+            this->m_data = new Data(wxStrdup(str), wxStrlen(str));
         return *this;
     }
 
     wxCharTypeBuffer& operator=(const wxCharTypeBuffer& src)
     {
-        if ( m_owned )
-            free(m_str);
-        CopyFrom(src);
+        wxScopedCharTypeBuffer<T>::operator=(src);
+        return *this;
+    }
+
+    wxCharTypeBuffer(const wxScopedCharTypeBuffer<T>& src)
+    {
+        this->MakeOwnedCopyOf(src);
+    }
+
+    wxCharTypeBuffer& operator=(const wxScopedCharTypeBuffer<T>& src)
+    {
+        MakeOwnedCopyOf(src);
         return *this;
     }
 
     bool extend(size_t len)
     {
-        wxASSERT_MSG( m_owned, _T("cannot extend non-owned buffer") );
+        wxASSERT_MSG( this->m_data->m_owned, "cannot extend non-owned buffer" );
+        wxASSERT_MSG( this->m_data->m_ref == 1, "can't extend shared buffer" );
 
-        CharType *
-            str = (CharType *)realloc(m_str, (len + 1)*sizeof(CharType));
+        CharType *str =
+            (CharType *)realloc(this->data(), (len + 1) * sizeof(CharType));
         if ( !str )
             return false;
 
-        m_str = str;
+        // For consistency with the ctor taking just the length, NUL-terminate
+        // the buffer.
+        str[len] = (CharType)0;
+
+        if ( this->m_data == this->GetNullData() )
+        {
+            this->m_data = new Data(str, len);
+        }
+        else
+        {
+            this->m_data->Set(str, len);
+            this->m_data->m_owned = true;
+        }
 
         return true;
     }
 
-    CharType *data() { return m_str; }
-    const CharType *data() const { return m_str; }
-    operator const CharType *() const { return m_str; }
-    CharType operator[](size_t n) const { return m_str[n]; }
-
-
-private:
-    CharType *DoRelease() const
+    void shrink(size_t len)
     {
-        CharType *p = m_str;
-        ((wxCharTypeBuffer *)this)->m_str = NULL;
-        return p;
-    }
+        wxASSERT_MSG( this->m_data->m_owned, "cannot shrink non-owned buffer" );
+        wxASSERT_MSG( this->m_data->m_ref == 1, "can't shrink shared buffer" );
 
-    void CopyFrom(const wxCharTypeBuffer& src)
-    {
-        m_owned = src.m_owned;
-        m_str = src.DoRelease();
-    }
+        wxASSERT( len <= this->length() );
 
-private:
-    CharType *m_str;
-    bool m_owned;
+        this->m_data->m_length = len;
+        this->data()[len] = 0;
+    }
 };
 
+WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxScopedCharTypeBuffer<char> )
+WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxCharTypeBuffer<char> )
+
 class wxCharBuffer : public wxCharTypeBuffer<char>
 {
 public:
     typedef wxCharTypeBuffer<char> wxCharTypeBufferBase;
+    typedef wxScopedCharTypeBuffer<char> wxScopedCharTypeBufferBase;
 
     wxCharBuffer(const wxCharTypeBufferBase& buf)
         : wxCharTypeBufferBase(buf) {}
+    wxCharBuffer(const wxScopedCharTypeBufferBase& buf)
+        : wxCharTypeBufferBase(buf) {}
 
     wxCharBuffer(const CharType *str = NULL) : wxCharTypeBufferBase(str) {}
     wxCharBuffer(size_t len) : wxCharTypeBufferBase(len) {}
@@ -164,33 +362,39 @@ public:
     wxCharBuffer(const wxCStrData& cstr);
 };
 
-#if wxUSE_WCHAR_T
+WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxScopedCharTypeBuffer<wchar_t> )
+WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxCharTypeBuffer<wchar_t> )
+
 class wxWCharBuffer : public wxCharTypeBuffer<wchar_t>
 {
 public:
     typedef wxCharTypeBuffer<wchar_t> wxCharTypeBufferBase;
+    typedef wxScopedCharTypeBuffer<wchar_t> wxScopedCharTypeBufferBase;
 
     wxWCharBuffer(const wxCharTypeBufferBase& buf)
         : wxCharTypeBufferBase(buf) {}
+    wxWCharBuffer(const wxScopedCharTypeBufferBase& buf)
+        : wxCharTypeBufferBase(buf) {}
 
     wxWCharBuffer(const CharType *str = NULL) : wxCharTypeBufferBase(str) {}
     wxWCharBuffer(size_t len) : wxCharTypeBufferBase(len) {}
 
     wxWCharBuffer(const wxCStrData& cstr);
 };
-#endif // wxUSE_WCHAR_T
 
 // wxCharTypeBuffer<T> implicitly convertible to T*
 template <typename T>
 class wxWritableCharTypeBuffer : public wxCharTypeBuffer<T>
 {
 public:
-    typedef typename wxCharTypeBuffer<T>::CharType CharType;
+    typedef typename wxScopedCharTypeBuffer<T>::CharType CharType;
 
-    wxWritableCharTypeBuffer(const wxCharTypeBuffer<T>& src)
+    wxWritableCharTypeBuffer(const wxScopedCharTypeBuffer<T>& src)
         : wxCharTypeBuffer<T>(src) {}
     // FIXME-UTF8: this won't be needed after converting mb_str()/wc_str() to
     //             always return a buffer
+    //             + we should derive this class from wxScopedCharTypeBuffer
+    //               then
     wxWritableCharTypeBuffer(const CharType *str = NULL)
         : wxCharTypeBuffer<T>(str) {}
 
@@ -235,7 +439,7 @@ public:
 
     friend class wxMemoryBuffer;
 
-    // everyting is private as it can only be used by wxMemoryBuffer
+    // everything is private as it can only be used by wxMemoryBuffer
 private:
     wxMemoryBufferData(size_t size = wxMemoryBufferData::DefBufSize)
         : m_data(size ? malloc(size) : NULL), m_size(size), m_len(0), m_ref(0)
@@ -267,6 +471,21 @@ private:
             delete this;
     }
 
+    void *release()
+    {
+        if ( m_data == NULL )
+            return NULL;
+
+        wxASSERT_MSG( m_ref == 1, "can't release shared buffer" );
+
+        void *p = m_data;
+        m_data = NULL;
+        m_len =
+        m_size = 0;
+
+        return p;
+    }
+
 
     // the buffer containing the data
     void  *m_data;
@@ -280,7 +499,7 @@ private:
     // the reference count
     size_t m_ref;
 
-    DECLARE_NO_COPY_CLASS(wxMemoryBufferData)
+    wxDECLARE_NO_COPY_CLASS(wxMemoryBufferData);
 };
 
 
@@ -306,9 +525,12 @@ public:
 
     wxMemoryBuffer& operator=(const wxMemoryBuffer& src)
     {
-        m_bufdata->DecRef();
-        m_bufdata = src.m_bufdata;
-        m_bufdata->IncRef();
+        if (&src != this)
+        {
+            m_bufdata->DecRef();
+            m_bufdata = src.m_bufdata;
+            m_bufdata->IncRef();
+        }
         return *this;
     }
 
@@ -318,6 +540,8 @@ public:
     size_t GetBufSize() const { return m_bufdata->m_size; }
     size_t GetDataLen() const { return m_bufdata->m_len; }
 
+    bool IsEmpty() const { return GetDataLen() == 0; }
+
     void   SetBufSize(size_t size) { m_bufdata->ResizeIfNeeded(size); }
     void   SetDataLen(size_t len)
     {
@@ -325,6 +549,8 @@ public:
         m_bufdata->m_len = len;
     }
 
+    void Clear() { SetDataLen(0); }
+
     // Ensure the buffer is big enough and return a pointer to it
     void *GetWriteBuf(size_t sizeNeeded)
     {
@@ -351,7 +577,7 @@ public:
     // Other ways to append to the buffer
     void  AppendByte(char data)
     {
-        wxCHECK_RET( m_bufdata->m_data, _T("invalid wxMemoryBuffer") );
+        wxCHECK_RET( m_bufdata->m_data, wxT("invalid wxMemoryBuffer") );
 
         m_bufdata->ResizeIfNeeded(m_bufdata->m_len + 1);
         *(((char*)m_bufdata->m_data) + m_bufdata->m_len) = data;
@@ -366,6 +592,13 @@ public:
 
     operator const char *() const { return (const char*)GetData(); }
 
+    // gives up ownership of data, returns the pointer; after this call,
+    // data isn't freed by the buffer and its content is resent to empty
+    void *release()
+    {
+        return m_bufdata->release();
+    }
+
 private:
     wxMemoryBufferData*  m_bufdata;
 };