Added class for requesting shared client-server memory

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9270 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/app/ServerMemIO.cpp

@@ -0,0 +1,197 @@
+//------------------------------------------------------------------------------
+//	Copyright (c) 2001-2002, Haiku
+//
+//	Permission is hereby granted, free of charge, to any person obtaining a
+//	copy of this software and associated documentation files (the "Software"),
+//	to deal in the Software without restriction, including without limitation
+//	the rights to use, copy, modify, merge, publish, distribute, sublicense,
+//	and/or sell copies of the Software, and to permit persons to whom the
+//	Software is furnished to do so, subject to the following conditions:
+//
+//	The above copyright notice and this permission notice shall be included in
+//	all copies or substantial portions of the Software.
+//
+//	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//	AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+//	FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+//	DEALINGS IN THE SOFTWARE.
+//
+//	File Name:		ServerMemIO.cpp
+//	Author(s):		Stefano Ceccherini ([email protected])
+//					The Storage Team
+//					DarkWyrm <[email protected]>
+//
+//	Description:	Adaptation of BMemoryIO code to allow for client-side usage
+//					of shared memory which is allocated by the server. Model is
+//					similar to BBitmap in this respect.
+//
+//------------------------------------------------------------------------------
+
+#include <algorithm>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+#include <AppServerLink.h>
+#include <ServerProtocol.h>
+#include "ServerMemIO.h"
+
+ServerMemIO::ServerMemIO(size_t size)
+		: fLen(0),
+		fPhys(0),
+		fPos(0)
+{
+	if(size>0)
+	{
+		BPrivate::BAppServerLink link;
+		link.StartMessage(AS_ACQUIRE_SERVERMEM);
+		link.Attach<size_t>(size);
+		link.Attach<port_id>(link.GetReplyPort());
+		link.Flush();
+		
+		int32 code;
+		link.GetNextReply(&code);
+		
+		if(code==SERVER_TRUE)
+		{
+			area_info ai;
+			
+			link.Read<area_id>(&fSourceArea);
+			link.Read<size_t>(&fOffset);
+			
+			if(fSourceArea>0 && get_area_info(fSourceArea,&ai)==B_OK)
+			{
+				fPhys=size;
+				
+				fArea=clone_area("ServerMemIO area",(void**)&fBuf,B_CLONE_ADDRESS,
+						B_READ_AREA|B_WRITE_AREA,fSourceArea);
+				
+				fBuf+=fOffset;
+			}
+			else
+			{
+				debugger("PANIC: bad data or something in ServerMemIO constructor");
+			}
+		}
+	}
+}
+
+
+// Destruction
+ServerMemIO::~ServerMemIO()
+{
+	BPrivate::BAppServerLink link;
+	link.StartMessage(AS_RELEASE_SERVERMEM);
+	link.Attach<area_id>(fSourceArea);
+	link.Attach<int32>(fOffset);
+	link.Flush();
+}
+
+
+// ReadAt
+ssize_t
+ServerMemIO::ReadAt(off_t pos, void *buffer, size_t size)
+{
+	if (buffer == NULL || pos < 0)
+		return B_BAD_VALUE;
+		
+	ssize_t sizeRead = 0;
+	if (pos < fLen) 
+	{
+		sizeRead = min_c(static_cast<off_t>(size), fLen - pos);
+		memcpy(buffer, fBuf + pos, sizeRead);
+	}
+	return sizeRead;
+}
+
+
+// WriteAt
+ssize_t
+ServerMemIO::WriteAt(off_t pos, const void *buffer, size_t size)
+{	
+	if (buffer == NULL || pos < 0)
+		return B_BAD_VALUE;
+		
+	ssize_t sizeWritten = 0;	
+	if (pos < fPhys) 
+	{
+		sizeWritten = min_c(static_cast<off_t>(size), fPhys - pos);
+		memcpy(fBuf + pos, buffer, sizeWritten);
+	}
+	
+	if (pos + sizeWritten > fLen)
+		fLen = pos + sizeWritten;
+						
+	return sizeWritten;
+}
+
+
+// Seek
+off_t
+ServerMemIO::Seek(off_t position, uint32 seek_mode)
+{
+	switch (seek_mode) 
+	{
+		case SEEK_SET:
+			fPos = position;
+			break;
+		case SEEK_CUR:
+			fPos += position;
+			break;		
+		case SEEK_END:
+			fPos = fLen + position;
+			break;
+		default:
+			break;
+	}	
+	return fPos;
+}
+
+
+// Position
+off_t
+ServerMemIO::Position() const
+{
+	return fPos;
+}
+
+
+// SetSize
+status_t
+ServerMemIO::SetSize(off_t size)
+{
+	return B_NOT_ALLOWED;
+}
+
+
+size_t
+ServerMemIO::GetSize(void) const
+{
+	return fLen;
+}
+
+
+void *
+ServerMemIO::GetPointer(void) const
+{
+	return (void*)fBuf;
+}
+
+
+// Private or Reserved
+ServerMemIO::ServerMemIO(const ServerMemIO &)
+{
+	//Copying not allowed
+}
+
+
+ServerMemIO &
+ServerMemIO::operator=(const ServerMemIO &)
+{
+	//Copying not allowed
+	return *this;
+}
+