MINOR: h2: add the connection and stream flags listing the causes for blocking
A demux may be prevented from receiving for the following reasons :
- no receive buffer could be allocated
- the receive buffer is full
- a response is needed and the mux is currently being used by a stream
- a response is needed and some room could not be found in the mux
buffer (either full or waiting for allocation)
- the stream buffer is waiting for allocation
- the stream buffer is full
A mux may stop accepting data for the following reasons :
- the buffer could not be allocated
- the buffer is full
A stream may stop sending data to a mux for the following reaons :
- the mux is busy processing another stream
- the mux buffer lacks room (full or not allocated)
- the mux's flow control prevents from sending
- the stream's flow control prevents from sending
All these conditions were turned into flags for use by the respective
places.
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 7f968c3..bdc2152 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -28,6 +28,20 @@
/* Connection flags (32 bit), in h2c->flags */
#define H2_CF_NONE 0x00000000
+/* Flags indicating why writing to the mux is blocked. */
+#define H2_CF_MUX_MALLOC 0x00000001 // mux blocked on lack of connection's mux buffer
+#define H2_CF_MUX_MFULL 0x00000002 // mux blocked on connection's mux buffer full
+#define H2_CF_MUX_BLOCK_ANY 0x00000003 // aggregate of the mux flags above
+
+/* Flags indicating why writing to the demux is blocked. */
+#define H2_CF_DEM_DALLOC 0x00000004 // demux blocked on lack of connection's demux buffer
+#define H2_CF_DEM_DFULL 0x00000008 // demux blocked on connection's demux buffer full
+#define H2_CF_DEM_MBUSY 0x00000010 // demux blocked on connection's mux side busy
+#define H2_CF_DEM_MROOM 0x00000020 // demux blocked on lack of room in mux buffer
+#define H2_CF_DEM_SALLOC 0x00000040 // demux blocked on lack of stream's request buffer
+#define H2_CF_DEM_SFULL 0x00000080 // demux blocked on stream request buffer full
+#define H2_CF_DEM_BLOCK_ANY 0x000000FC // aggregate of the demux flags above
+
/* H2 connection state, in h2c->st0 */
enum h2_cs {
H2_CS_PREFACE, // init done, waiting for connection preface
@@ -104,6 +118,13 @@
#define H2_SF_RST_RCVD 0x00000004 // received RST_STREAM
#define H2_SF_RST_SENT 0x00000008 // sent RST_STREAM
+/* stream flags indicating the reason the stream is blocked */
+#define H2_SF_BLK_MBUSY 0x00000010 // blocked waiting for mux access (transient)
+#define H2_SF_BLK_MROOM 0x00000020 // blocked waiting for room in the mux
+#define H2_SF_BLK_MFCTL 0x00000040 // blocked due to mux fctl
+#define H2_SF_BLK_SFCTL 0x00000080 // blocked due to stream fctl
+#define H2_SF_BLK_ANY 0x000000F0 // any of the reasons above
+
/* H2 stream descriptor, describing the stream as it appears in the H2C, and as
* it is being processed in the internal HTTP representation (H1 for now).
*/