Added AttributeDataReader, a DataReader implementation for attributes.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@34053 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/bin/package/DataReader.cpp

@@ -10,6 +10,8 @@
 #include <string.h>
 #include <unistd.h>
 
+#include <fs_attr.h>
+
 
 // #pragma mark - DataReader
 
@@ -39,6 +41,30 @@ FDDataReader::ReadData(off_t offset, void* buffer, size_t size)
 }
 
 
+// #pragma mark - AttributeDataReader
+
+
+AttributeDataReader::AttributeDataReader(int fd, const char* attribute,
+	uint32 type)
+	:
+	fFD(fd),
+	fType(type),
+	fAttribute(attribute)
+{
+}
+
+
+status_t
+AttributeDataReader::ReadData(off_t offset, void* buffer, size_t size)
+{
+	ssize_t bytesRead = fs_read_attr(fFD, fAttribute, fType, offset, buffer,
+		size);
+	if (bytesRead < 0)
+		return errno;
+	return (size_t)bytesRead == size ? B_OK : B_ERROR;
+}
+
+
 // #pragma mark - BufferDataReader
 
 

src/bin/package/DataReader.h

@@ -30,6 +30,21 @@ private:
 };
 
 
+class AttributeDataReader : public DataReader {
+public:
+								AttributeDataReader(int fd,
+									const char* attribute, uint32 type);
+
+	virtual	status_t			ReadData(off_t offset, void* buffer,
+									size_t size);
+
+private:
+			int					fFD;
+			uint32				fType;
+			const char*			fAttribute;
+};
+
+
 class BufferDataReader : public DataReader {
 public:
 								BufferDataReader(const void* data, size_t size);