Streams: export iteration API.

This commit is contained in:
antirez
2017-09-15 12:17:25 +02:00
parent 9ed40f0fc3
commit 01ea018c40
3 changed files with 31 additions and 24 deletions

View File

@ -19,4 +19,35 @@ typedef struct stream {
streamID last_id; /* Zero if there are yet no items. */
} stream;
/* We define an iterator to iterate stream items in an abstract way, without
* caring about the radix tree + listpack representation. Technically speaking
* the iterator is only used inside streamReplyWithRange(), so could just
* be implemented inside the function, but practically there is the AOF
* rewriting code that also needs to iterate the stream to emit the XADD
* commands. */
typedef struct streamIterator {
uint64_t start_key[2]; /* Start key as 128 bit big endian. */
uint64_t end_key[2]; /* End key as 128 bit big endian. */
raxIterator ri; /* Rax iterator. */
unsigned char *lp; /* Current listpack. */
unsigned char *lp_ele; /* Current listpack cursor. */
/* Buffers used to hold the string of lpGet() when the element is
* integer encoded, so that there is no string representation of the
* element inside the listpack itself. */
unsigned char field_buf[LP_INTBUF_SIZE];
unsigned char value_buf[LP_INTBUF_SIZE];
} streamIterator;
/* Prototypes of exported APIs. */
struct client;
stream *streamNew(void);
void freeStream(stream *s);
size_t streamReplyWithRange(struct client *c, stream *s, streamID *start, streamID *end, size_t count);
void streamIteratorStart(streamIterator *si, stream *s, streamID *start, streamID *end);
int streamIteratorGetID(streamIterator *si, streamID *id, int64_t *numfields);
void streamIteratorGetField(streamIterator *si, unsigned char **fieldptr, unsigned char **valueptr, int64_t *fieldlen, int64_t *valuelen);
void streamIteratorStop(streamIterator *si);
#endif