Streams: export iteration API.

src/server.h

@@ -1425,11 +1425,6 @@ void listTypeConvert(robj *subject, int enc);
 void unblockClientWaitingData(client *c);
 void popGenericCommand(client *c, int where);
 
-/* Stream data type. */
-stream *streamNew(void);
-void freeStream(stream *s);
-size_t streamReplyWithRange(client *c, stream *s, streamID *start, streamID *end, size_t count);
-
 /* MULTI/EXEC/WATCH... */
 void unwatchAllKeys(client *c);
 void initClientMultiState(client *c);

src/stream.h

@@ -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

src/t_stream.c

@@ -196,25 +196,6 @@ int streamAppendItem(stream *s, robj **argv, int numfields, streamID *added_id,
     return C_OK;
 }
 
-/* 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;
-
 /* Initialize the stream iterator, so that we can call iterating functions
  * to get the next items. This requires a corresponding streamIteratorStop()
  * at the end.