MEDIUM: filters: Add pre and post analyzer callbacks

'channel_analyze' callback has been removed. Now, there are 2 callbacks to
surround calls to analyzers:

  * channel_pre_analyze: Called BEFORE all filterable analyzers. it can be
    called many times for the same analyzer, once at each loop until the
    analyzer finishes its processing. This callback is resumable, it returns a
    negative value if an error occurs, 0 if it needs to wait, any other value
    otherwise.

  * channel_post_analyze: Called AFTER all filterable analyzers. Here, AFTER
    means when an analyzer finishes its processing. This callback is NOT
    resumable, it returns a negative value if an error occurs, any other value
    otherwise.

Pre and post analyzer callbacks are not automatically called. 'pre_analyzers'
and 'post_analyzers' bit fields in the filter structure must be set to the right
value using AN_* flags (see include/types/channel.h).

The flag AN_RES_ALL has been added (AN_REQ_ALL already exists) to ease the life
of filter developers. AN_REQ_ALL and AN_RES_ALL include all filterable
analyzers.
diff --git a/include/proto/filters.h b/include/proto/filters.h
index 7020285..c351f6e 100644
--- a/include/proto/filters.h
+++ b/include/proto/filters.h
@@ -114,7 +114,8 @@
 void flt_http_reply(struct stream *s, short status, const struct chunk *msg);
 
 int  flt_start_analyze(struct stream *s, struct channel *chn, unsigned int an_bit);
-int  flt_analyze(struct stream *s, struct channel *chn, unsigned int an_bit);
+int  flt_pre_analyze(struct stream *s, struct channel *chn, unsigned int an_bit);
+int  flt_post_analyze(struct stream *s, struct channel *chn, unsigned int an_bit);
 int  flt_analyze_http_headers(struct stream *s, struct channel *chn, unsigned int an_bit);
 int  flt_end_analyze(struct stream *s, struct channel *chn, unsigned int an_bit);
 
diff --git a/include/types/channel.h b/include/types/channel.h
index b31f493..dd50993 100644
--- a/include/types/channel.h
+++ b/include/types/channel.h
@@ -156,6 +156,7 @@
 #define AN_RES_HTTP_PROCESS_FE  0x00040000  /* process frontend's HTTP part (same for now) */
 #define AN_RES_STORE_RULES      0x00080000  /* table persistence matching */
 #define AN_RES_HTTP_XFER_BODY   0x00100000  /* forward response body */
+#define AN_RES_ALL              0x001f0000  /* all of the response analysers */
 
 #define AN_FLT_START_FE         0x01000000
 #define AN_FLT_START_BE         0x02000000
diff --git a/include/types/filters.h b/include/types/filters.h
index e01e225..62fcfb1 100644
--- a/include/types/filters.h
+++ b/include/types/filters.h
@@ -77,10 +77,14 @@
  *  - channel_start_analyze: Called when a filter starts to analyze a channel.
  *                          Returns a negative value if an error occurs, 0 if
  *                          it needs to wait, any other value otherwise.
- *  - channel_analyze     : Called before each analyzer attached to a channel,
+ *  - channel_pre_analyze : Called before each analyzer attached to a channel,
  *                          expects analyzers responsible for data sending.
  *                          Returns a negative value if an error occurs, 0 if
  *                          it needs to wait, any other value otherwise.
+ *  - channel_post_analyze: Called after each analyzer attached to a channel,
+ *                          expects analyzers responsible for data sending.
+ *                          Returns a negative value if an error occurs,
+ *                          any other value otherwise.
  *  - channel_end_analyze : Called when all other analyzers have finished their
  *                          processing.
  *                          Returns a negative value if an error occurs, 0 if
@@ -140,7 +144,8 @@
 	 * Channel callbacks
 	 */
 	int  (*channel_start_analyze)(struct stream *s, struct filter *f, struct channel *chn);
-	int  (*channel_analyze)      (struct stream *s, struct filter *f, struct channel *chn, unsigned int an_bit);
+	int  (*channel_pre_analyze)  (struct stream *s, struct filter *f, struct channel *chn, unsigned int an_bit);
+	int  (*channel_post_analyze) (struct stream *s, struct filter *f, struct channel *chn, unsigned int an_bit);
 	int  (*channel_end_analyze)  (struct stream *s, struct filter *f, struct channel *chn);
 
 	/*
@@ -202,6 +207,8 @@
 	                                    * 0: request channel, 1: response channel */
 	unsigned int    fwd[2];            /* Offset, relative to buf->p, to the next byte to forward for a specific channel
 	                                    * 0: request channel, 1: response channel */
+	unsigned int    pre_analyzers;     /* bit field indicating analyzers to pre-process */
+	unsigned int    post_analyzers;    /* bit field indicating analyzers to post-process */
 	struct list     list;              /* Next filter for the same proxy/stream */
 };
 
diff --git a/src/filters.c b/src/filters.c
index 051aa48..139440d 100644
--- a/src/filters.c
+++ b/src/filters.c
@@ -656,20 +656,23 @@
 }
 
 /*
- * Calls 'channel_analyze' callback for all filters attached to a stream. This
- * function is called before each analyzer attached to a channel, expects
- * analyzers responsible for data sending. 'channel_analyze' callback is
- * resumable, so this function returns 0 if an error occurs or if it needs to
- * wait, any other value otherwise.
+ * Calls 'channel_pre_analyze' callback for all filters attached to a
+ * stream. This function is called BEFORE each analyzer attached to a channel,
+ * expects analyzers responsible for data sending. 'channel_pre_analyze'
+ * callback is resumable, so this function returns 0 if an error occurs or if it
+ * needs to wait, any other value otherwise.
+ *
+ * Note this function can be called many times for the same analyzer. In fact,
+ * it is called until the analyzer finishes its processing.
  */
 int
-flt_analyze(struct stream *s, struct channel *chn, unsigned int an_bit)
+flt_pre_analyze(struct stream *s, struct channel *chn, unsigned int an_bit)
 {
 	int ret = 1;
 
 	RESUME_FILTER_LOOP(s, chn) {
-		if (FLT_OPS(filter)->channel_analyze) {
-			ret = FLT_OPS(filter)->channel_analyze(s, filter, chn, an_bit);
+		if (FLT_OPS(filter)->channel_pre_analyze && (filter->pre_analyzers & an_bit)) {
+			ret = FLT_OPS(filter)->channel_pre_analyze(s, filter, chn, an_bit);
 			if (ret <= 0)
 				BREAK_EXECUTION(s, chn, check_result);
 		}
@@ -680,6 +683,31 @@
 }
 
 /*
+ * Calls 'channel_post_analyze' callback for all filters attached to a
+ * stream. This function is called AFTER each analyzer attached to a channel,
+ * expects analyzers responsible for data sending. 'channel_post_analyze'
+ * callback is NOT resumable, so this function returns a 0 if an error occurs,
+ * any other value otherwise.
+ *
+ * Here, AFTER means when the analyzer finishes its processing.
+ */
+int
+flt_post_analyze(struct stream *s, struct channel *chn, unsigned int an_bit)
+{
+	struct filter *filter;
+	int            ret = 1;
+
+	list_for_each_entry(filter, &strm_flt(s)->filters, list) {
+		if (FLT_OPS(filter)->channel_post_analyze &&  (filter->post_analyzers & an_bit)) {
+			ret = FLT_OPS(filter)->channel_post_analyze(s, filter, chn, an_bit);
+			if (ret < 0)
+				break;
+		}
+	}
+	return handle_analyzer_result(s, chn, 0, ret);
+}
+
+/*
  * This function is the AN_FLT_HTTP_HDRS analyzer, used to filter HTTP headers
  * or a request or a response. Returns 0 if an error occurs or if it needs to
  * wait, any other value otherwise.
diff --git a/src/flt_trace.c b/src/flt_trace.c
index 8a9d14d..a052ab5 100644
--- a/src/flt_trace.c
+++ b/src/flt_trace.c
@@ -145,7 +145,8 @@
 	STRM_TRACE(conf, s, "%-25s: channel=%-10s - mode=%-5s (%s)",
 		   __FUNCTION__,
 		   channel_label(chn), proxy_mode(s), stream_pos(s));
-	register_data_filter(s, chn, filter);
+	filter->pre_analyzers  |= (AN_REQ_ALL | AN_RES_ALL);
+	filter->post_analyzers |= (AN_REQ_ALL | AN_RES_ALL);
 	return 1;
 }
 
@@ -216,10 +217,11 @@
 			ana = "unknown";
 	}
 
-	STRM_TRACE(conf, s, "%-25s: channel=%-10s - mode=%-5s (%s) - analyzer=%s",
+	STRM_TRACE(conf, s, "%-25s: channel=%-10s - mode=%-5s (%s) - "
+		   "analyzer=%s - step=%s",
 		   __FUNCTION__,
 		   channel_label(chn), proxy_mode(s), stream_pos(s),
-		   ana);
+		   ana, ((chn->analysers & an_bit) ? "PRE" : "POST"));
 	return 1;
 }
 
@@ -413,7 +415,8 @@
 
 	/* Handle channels activity */
 	.channel_start_analyze = trace_chn_start_analyze,
-	.channel_analyze       = trace_chn_analyze,
+	.channel_pre_analyze   = trace_chn_analyze,
+	.channel_post_analyze  = trace_chn_analyze,
 	.channel_end_analyze   = trace_chn_end_analyze,
 
 	/* Filter HTTP requests and responses */
diff --git a/src/stream.c b/src/stream.c
index 24eba1b..2ca3b36 100644
--- a/src/stream.c
+++ b/src/stream.c
@@ -1498,17 +1498,19 @@
 
 /* These 2 following macros call an analayzer for the specified channel if the
  * right flag is set. The first one is used for "filterable" analyzers. If a
- * stream has some registered filters, 'channel_analyaze' callback is called.
- * The second are used for other analyzers (AN_FLT_* and
+ * stream has some registered filters, pre and post analyaze callbacks are
+ * called. The second are used for other analyzers (AN_FLT_* and
  * AN_REQ/RES_HTTP_XFER_BODY) */
 #define FLT_ANALYZE(strm, chn, fun, list, back, flag, ...)			\
 	{									\
 		if ((list) & (flag)) {						\
 			if (HAS_FILTERS(strm)) {			        \
-				if (!flt_analyze((strm), (chn), (flag)))        \
+				if (!flt_pre_analyze((strm), (chn), (flag)))    \
 					break;				        \
 				if (!fun((strm), (chn), (flag), ##__VA_ARGS__))	\
 					break;					\
+				if (!flt_post_analyze((strm), (chn), (flag)))	\
+					break;					\
 			}							\
 			else {							\
 				if (!fun((strm), (chn), (flag), ##__VA_ARGS__))	\