From f5ef4d69b7fd4fb89203cd3cf9dd1e42fda7831f Mon Sep 17 00:00:00 2001 From: Vadim Zeitlin Date: Mon, 16 Apr 2012 13:53:45 +0000 Subject: [PATCH] Added wxWrapperInputStream class. This stream allows to wrap another stream. This is a useful base class for adapter classes providing stream interface on top of something else, like the upcoming wxFSInputStream. See #14185. git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71205 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775 --- include/wx/stream.h | 48 +++++++++++++++++++++++ interface/wx/stream.h | 54 ++++++++++++++++++++++++++ src/common/stream.cpp | 88 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 190 insertions(+) diff --git a/include/wx/stream.h b/include/wx/stream.h index ed07ce61a8..80c81bcbdc 100644 --- a/include/wx/stream.h +++ b/include/wx/stream.h @@ -640,6 +640,54 @@ protected: inline wxStreamBuffer *wxBufferedOutputStream::OutputStreamBuffer() const { return m_o_streambuf; } #endif // WXWIN_COMPATIBILITY_2_6 +// --------------------------------------------------------------------------- +// wxWrapperInputStream: forwards all IO to another stream. +// --------------------------------------------------------------------------- + +class WXDLLIMPEXP_BASE wxWrapperInputStream : public wxFilterInputStream +{ +public: + // Constructor fully initializing the stream. The overload taking pointer + // takes ownership of the parent stream, the one taking reference does not. + // + // Notice that this class also has a default ctor but it's protected as the + // derived class is supposed to take care of calling InitParentStream() if + // it's used. + wxWrapperInputStream(wxInputStream& stream); + wxWrapperInputStream(wxInputStream* stream); + + // Override the base class methods to forward to the wrapped stream. + virtual wxFileOffset GetLength() const; + virtual bool IsSeekable() const; + +protected: + virtual size_t OnSysRead(void *buffer, size_t size); + virtual wxFileOffset OnSysSeek(wxFileOffset pos, wxSeekMode mode); + virtual wxFileOffset OnSysTell() const; + + // Ensure that our own last error is the same as that of the real stream. + // + // This method is const because the error must be updated even from const + // methods (in other words, it really should have been mutable in the first + // place). + void SynchronizeLastError() const + { + const_cast(this)-> + Reset(m_parent_i_stream->GetLastError()); + } + + // Default constructor, use InitParentStream() later. + wxWrapperInputStream(); + + // Set up the wrapped stream for an object initialized using the default + // constructor. The ownership logic is the same as above. + void InitParentStream(wxInputStream& stream); + void InitParentStream(wxInputStream* stream); + + wxDECLARE_NO_COPY_CLASS(wxWrapperInputStream); +}; + + #endif // wxUSE_STREAMS #endif // _WX_WXSTREAM_H__ diff --git a/interface/wx/stream.h b/interface/wx/stream.h index 99740280a7..6fd27a4126 100644 --- a/interface/wx/stream.h +++ b/interface/wx/stream.h @@ -1066,3 +1066,57 @@ public: }; +/** + @class wxWrapperInputStream + + A wrapper input stream is a kind of filter stream which forwards all the + operations to its base stream. This is useful to build utility classes such + as wxFSInputStream. + + @note + The interface of this class is the same as that of wxInputStream. + Only a constructor differs and it is documented below. + + @library{wxbase} + @category{streams} + + @see wxFSInputStream, wxFilterInputStream + @since 2.9.4 +*/ +class wxWrapperInputStream : public wxFilterInputStream +{ +public: + //@{ + /** + Initializes a wrapper stream. + + If the parent stream is passed as a pointer then the new wrapper stream + takes ownership of it. If it is passed by reference then it does not. + */ + wxWrapperInputStream(wxInputStream& stream); + wxWrapperInputStream(wxInputStream* stream); + //@} + +protected: + /** + Default constructor, use InitParentStream() to finish initialization. + + This constructor can be used by the derived classes from their own + constructors when the parent stream can't be specified immediately. + The derived class must call InitParentStream() later to do it. + */ + wxWrapperInputStream(); + + //@{ + /** + Set up the wrapped stream for an object initialized using the default + constructor. + + The ownership logic is the same as for the non-default constructor, + i.e. this object takes ownership of the stream if it's passed by + pointer but not if it's passed by reference. + */ + void InitParentStream(wxInputStream& stream); + void InitParentStream(wxInputStream* stream); + //@} +}; diff --git a/src/common/stream.cpp b/src/common/stream.cpp index 1a03caa346..4fe8a17cab 100644 --- a/src/common/stream.cpp +++ b/src/common/stream.cpp @@ -36,6 +36,7 @@ #include #include "wx/datstrm.h" #include "wx/textfile.h" +#include "wx/scopeguard.h" // ---------------------------------------------------------------------------- // constants @@ -1446,6 +1447,93 @@ void wxBufferedOutputStream::SetOutputStreamBuffer(wxStreamBuffer *buffer) m_o_streambuf = buffer; } +// --------------------------------------------------------------------------- +// wxWrapperInputStream implementation +// --------------------------------------------------------------------------- + +wxWrapperInputStream::wxWrapperInputStream() +{ + m_lasterror = wxSTREAM_READ_ERROR; +} + +wxWrapperInputStream::wxWrapperInputStream(wxInputStream& stream) + : wxFilterInputStream(stream) +{ + SynchronizeLastError(); +} + +wxWrapperInputStream::wxWrapperInputStream(wxInputStream *stream) + : wxFilterInputStream(stream) +{ + if ( m_parent_i_stream ) + SynchronizeLastError(); + else + m_lasterror = wxSTREAM_READ_ERROR; +} + +void wxWrapperInputStream::InitParentStream(wxInputStream& stream) +{ + wxCHECK_RET( !m_parent_i_stream, "Can't init parent stream twice" ); + + m_parent_i_stream = &stream; + + SynchronizeLastError(); +} + +void wxWrapperInputStream::InitParentStream(wxInputStream* stream) +{ + wxCHECK_RET( !m_parent_i_stream, "Can't init parent stream twice" ); + + m_parent_i_stream = stream; + + if ( m_parent_i_stream ) + { + m_owns = true; + + SynchronizeLastError(); + } +} + +wxFileOffset wxWrapperInputStream::GetLength() const +{ + wxCHECK_MSG(m_parent_i_stream, wxInvalidOffset, "Stream not valid"); + + wxON_BLOCK_EXIT_THIS0(wxWrapperInputStream::SynchronizeLastError); + return m_parent_i_stream->GetLength(); +} + +bool wxWrapperInputStream::IsSeekable() const +{ + wxCHECK_MSG(m_parent_i_stream, false, "Stream not valid"); + return m_parent_i_stream->IsSeekable(); +} + +size_t wxWrapperInputStream::OnSysRead(void *buffer, size_t size) +{ + wxCHECK_MSG(m_parent_i_stream, false, "Stream not valid"); + + wxON_BLOCK_EXIT_THIS0(wxWrapperInputStream::SynchronizeLastError); + + m_parent_i_stream->Read(buffer, size); + return m_parent_i_stream->LastRead(); +} + +wxFileOffset wxWrapperInputStream::OnSysSeek(wxFileOffset pos, wxSeekMode mode) +{ + wxCHECK_MSG(IsSeekable(), false, "Stream not seekable"); + + wxON_BLOCK_EXIT_THIS0(wxWrapperInputStream::SynchronizeLastError); + return m_parent_i_stream->SeekI (pos, mode); +} + +wxFileOffset wxWrapperInputStream::OnSysTell() const +{ + wxCHECK_MSG(m_parent_i_stream, false, "Stream not valid"); + + wxON_BLOCK_EXIT_THIS0(wxWrapperInputStream::SynchronizeLastError); + return m_parent_i_stream->TellI(); +} + // ---------------------------------------------------------------------------- // Some IOManip function // ---------------------------------------------------------------------------- -- 2.45.2