12 typedef struct Source Source;  typedef
127 struct Source {  struct
135 	Source	*parent;	/* immutable */  argument
136 	File	*file;		/* immutable; point back */
138 	QLock	lk;
139 	int	ref;
149 	u32int	epoch;
150 	Block	*b;		/* block containing this source */
151 	uchar	score[VtScoreSize]; /* score of block containing this source */
152 	u32int	scoreEpoch;	/* epoch of block containing this source */
153 	int	epb;		/* immutable: entries per block in parent */
154 	u32int	tag;		/* immutable: tag of parent */
155 	u32int	offset; 	/* immutable: entry offset in parent */