MINOR: sample: Replace "req.ungrpc" smp fetch by a "ungrpc" converter.

This patch simply extracts the code of smp_fetch_req_ungrpc() for "req.ungrpc"
from http_fetch.c to move it to sample.c with very few modifications.
Furthermore smp_fetch_body_buf() used to fetch the body contents is no more needed.

Update the documentation for gRPC.
diff --git a/doc/configuration.txt b/doc/configuration.txt
index 75383f8..3ce29ca 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -13792,17 +13792,11 @@
   contain characters 'a-z', 'A-Z', '0-9', '.' and '_'.
 
 svarint
-  Converts a binary input sample of a protocol buffers signed "varints" ("sint32"
+  Converts a binary input sample of a protocol buffers signed "varint" ("sint32"
   and "sint64") to an integer.
-  More information may be found here about the protocol buffers message types:
+  More information may be found here about the protocol buffers message field types:
   https://developers.google.com/protocol-buffers/docs/encoding
 
-varint
-  Converts a binary input sample of a protocol buffers "varints", excepted
-  the signed ones "sint32" and "sint64", to an integer.
-  More information may be found here about the protocol buffers message types:
-  https://developers.google.com/protocol-buffers/docs/encoding
-
 table_bytes_in_rate(<table>)
   Uses the string representation of the input sample to perform a look up in
   the specified table. If the key is not found in the table, integer value zero
@@ -13973,6 +13967,39 @@
   Takes an url-encoded string provided as input and returns the decoded
   version as output. The input and the output are of type string.
 
+ungrpc(<field_number>) : binary
+  This extracts the protocol buffers message field in raw mode of an input binary
+  sample with <field_number> as field number (dotted notation).
+
+  Example:
+    // with such a protocol buffer .proto file content adapted from
+    // https://github.com/grpc/grpc/blob/master/examples/protos/route_guide.proto
+
+    message Point {
+      int32 latitude = 1;
+      int32 longitude = 2;
+    }
+
+    message PPoint {
+      Point point = 59;
+    }
+
+    message Rectangle {
+      // One corner of the rectangle.
+      PPoint lo = 48;
+      // The other corner of the rectangle.
+      PPoint hi = 49;
+    }
+
+    let's say a body request is made of a "Rectangle" object value (two PPoint
+    protocol buffers messages), the four protocol buffers fields could be
+    extracted with these "ungrpc" directives:
+
+    req.body,ungrpc(48.59.1) # "latitude" of "lo" first PPoint
+    req.body,ungrpc(48.59.2) # "longitude" of "lo" first PPoint
+    req.body,ungrpc(49.59.1) # "latidude" of "hi" second PPoint
+    req.body,ungrpc(49.59.2) # "longitude" of "hi" second PPoint
+
 unset-var(<var name>)
   Unsets a variable if the input content is defined. The name of the variable
   starts with an indication about its scope. The scopes allowed are:
@@ -13999,6 +14026,12 @@
       # e.g.  20140710162350 127.0.0.1:57325
       log-format %[date,utime(%Y%m%d%H%M%S)]\ %ci:%cp
 
+varint
+  Converts a binary input sample of a protocol buffers "varint", excepted
+  the signed ones "sint32" and "sint64", to an integer.
+  More information may be found here about the protocol buffers message field types:
+  https://developers.google.com/protocol-buffers/docs/encoding
+
 word(<index>,<delimiters>[,<count>])
   Extracts the nth word counting from the beginning (positive index) or from
   the end (negative index) considering given delimiters from an input string.
@@ -15976,38 +16009,6 @@
   the first one. Negative values indicate positions relative to the last one,
   with -1 being the last one. A typical use is with the X-Forwarded-For header.
 
-req.ungrpc(<field_number>) : binary
-  This extracts the protocol buffers message in raw mode of a gRPC request body
-  with <field_number> as terminal field number (dotted notation).
-
-  Example:
-    // with such a protocol buffer .proto file content adapted from
-    // https://github.com/grpc/grpc/blob/master/examples/protos/route_guide.proto
-
-    message Point {
-      int32 latitude = 1;
-      int32 longitude = 2;
-    }
-
-    message PPoint {
-      Point point = 59;
-    }
-
-    message Rectangle {
-      // One corner of the rectangle.
-      PPoint lo = 48;
-      // The other corner of the rectangle.
-      PPoint hi = 49;
-    }
-
-  Let's say a body requests is made of a "Rectangle" object value (two PPoint
-  protocol buffers messages), the four protocol buffers messages could be fetched
-  with this "req.ungrpc" sample fetch directives:
-
-    req.ungrpc(48.59.1) # "latitude" of "lo" first PPoint
-    req.ungrpc(48.59.2) # "longitude" of "lo" first PPoint
-    req.ungrpc(49.59.1) # "latidude" of "hi" second PPoint
-    req.ungrpc(49.59.2) # "longitude" of "hi" second PPoint
 
 
 http_auth(<userlist>) : boolean
diff --git a/src/http_fetch.c b/src/http_fetch.c
index 8f88646..51f2ef1 100644
--- a/src/http_fetch.c
+++ b/src/http_fetch.c
@@ -39,7 +39,6 @@
 #include <proto/log.h>
 #include <proto/obj_type.h>
 #include <proto/proto_http.h>
-#include <proto/protocol_buffers.h>
 #include <proto/sample.h>
 #include <proto/stream.h>
 
@@ -1517,245 +1516,6 @@
 	return ret;
 }
 
-static inline struct buffer *
-smp_fetch_body_buf(const struct arg *args, struct sample *smp)
-{
-	struct buffer *buf;
-
-	if (IS_HTX_SMP(smp) || (smp->px->mode == PR_MODE_TCP)) {
-		/* HTX version */
-		struct htx *htx = smp_prefetch_htx(smp, args);
-		int32_t pos;
-
-		if (!htx)
-			return NULL;
-
-		buf = get_trash_chunk();
-		for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
-			struct htx_blk *blk = htx_get_blk(htx, pos);
-			enum htx_blk_type type = htx_get_blk_type(blk);
-
-			if (type == HTX_BLK_EOM || type == HTX_BLK_EOD)
-				break;
-			if (type == HTX_BLK_DATA) {
-				if (!htx_data_to_h1(htx_get_blk_value(htx, blk), buf, 0))
-					return NULL;
-			}
-		}
-	}
-	else {
-		/* LEGACY version */
-		struct http_msg *msg;
-		unsigned long len;
-		unsigned long block1;
-		char *body;
-
-		if (smp_prefetch_http(smp->px, smp->strm, smp->opt, args, smp, 1) <= 0)
-			return NULL;
-
-		if ((smp->opt & SMP_OPT_DIR) == SMP_OPT_DIR_REQ)
-			msg = &smp->strm->txn->req;
-		else
-			msg = &smp->strm->txn->rsp;
-
-		len  = http_body_bytes(msg);
-		body = c_ptr(msg->chn, -http_data_rewind(msg));
-
-		block1 = len;
-		if (block1 > b_wrap(&msg->chn->buf) - body)
-			block1 = b_wrap(&msg->chn->buf) - body;
-
-		buf = get_trash_chunk();
-		if (block1 == len) {
-			/* buffer is not wrapped (or empty) */
-			memcpy(buf->area, body, len);
-		}
-		else {
-			/* buffer is wrapped, we need to defragment it */
-			memcpy(buf->area, body, block1);
-			memcpy(buf->area + block1, b_orig(&msg->chn->buf),
-			       len - block1);
-		}
-		buf->data = len;
-	}
-
-	return buf;
-}
-
-#define GRPC_MSG_COMPRESS_FLAG_SZ 1 /* 1 byte */
-#define GRPC_MSG_LENGTH_SZ        4 /* 4 bytes */
-#define GRPC_MSG_HEADER_SZ        (GRPC_MSG_COMPRESS_FLAG_SZ + GRPC_MSG_LENGTH_SZ)
-
-/*
- * Fetch a gRPC field value. Takes a mandatory argument: the field identifier
- * (dotted notation) internally represented as an array of unsigned integers
- * and its size.
- * Return 1 if the field was found, 0 if not.
- */
-static int smp_fetch_req_ungrpc(const struct arg *args, struct sample *smp, const char *kw, void *private)
-{
-	struct buffer *body;
-	unsigned char *pos;
-	size_t grpc_left;
-	unsigned int *fid;
-	size_t fid_sz;
-
-	if (!smp->strm)
-		return 0;
-
-	fid = args[0].data.fid.ids;
-	fid_sz = args[0].data.fid.sz;
-
-	body = smp_fetch_body_buf(args, smp);
-	if (!body)
-		return 0;
-
-	pos = (unsigned char *)body->area;
-	/* Remaining bytes in the body to be parsed. */
-	grpc_left = body->data;
-
-	while (grpc_left > GRPC_MSG_COMPRESS_FLAG_SZ + GRPC_MSG_LENGTH_SZ) {
-		int next_field, found;
-		size_t grpc_msg_len, left;
-		unsigned int wire_type, field_number;
-		uint64_t key, elen;
-
-		grpc_msg_len = left = ntohl(*(uint32_t *)(pos + GRPC_MSG_COMPRESS_FLAG_SZ));
-
-		pos += GRPC_MSG_HEADER_SZ;
-		grpc_left -= GRPC_MSG_HEADER_SZ;
-
-		if (grpc_left < left)
-			return 0;
-
-		found = 1;
-		/* Length of the length-delimited messages if any. */
-		elen = 0;
-
-		/* Message decoding: there may be serveral key+value protobuf pairs by
-		 * gRPC message.
-		 */
-		next_field = 0;
-		while (next_field < fid_sz) {
-			uint64_t sleft;
-
-			if ((ssize_t)left <= 0)
-				return 0;
-
-			/* Remaining bytes saving. */
-			sleft = left;
-
-			/* Key decoding */
-			if (!protobuf_decode_varint(&key, &pos, &left))
-				return 0;
-
-			wire_type = key & 0x7;
-			field_number = key >> 3;
-			found = field_number == fid[next_field];
-
-			if (found && field_number != fid[next_field])
-				found = 0;
-
-			switch (wire_type) {
-			case PBUF_TYPE_VARINT:
-			{
-				if (!found) {
-					protobuf_skip_varint(&pos, &left);
-				} else if (next_field == fid_sz - 1) {
-					int varint_len;
-					unsigned char *spos = pos;
-
-					varint_len = protobuf_varint_getlen(&pos, &left);
-					if (varint_len == -1)
-						return 0;
-
-					smp->data.type = SMP_T_BIN;
-					smp->data.u.str.area = (char *)spos;
-					smp->data.u.str.data = varint_len;
-					smp->flags = SMP_F_VOL_TEST;
-					return 1;
-				}
-				break;
-			}
-
-			case PBUF_TYPE_64BIT:
-			{
-				if (!found) {
-					pos += sizeof(uint64_t);
-					left -= sizeof(uint64_t);
-				} else if (next_field == fid_sz - 1) {
-					smp->data.type = SMP_T_BIN;
-					smp->data.u.str.area = (char *)pos;
-					smp->data.u.str.data = sizeof(uint64_t);
-					smp->flags = SMP_F_VOL_TEST;
-					return 1;
-				}
-				break;
-			}
-
-			case PBUF_TYPE_LENGTH_DELIMITED:
-			{
-				/* Decode the length of this length-delimited field. */
-				if (!protobuf_decode_varint(&elen, &pos, &left))
-					return 0;
-
-				if (elen > left)
-					return 0;
-
-				/* The size of the current field is computed from here do skip
-				 * the bytes to encode the previous lenght.*
-				 */
-				sleft = left;
-				if (!found) {
-					/* Skip the current length-delimited field. */
-					pos += elen;
-					left -= elen;
-					break;
-				} else if (next_field == fid_sz - 1) {
-					smp->data.type = SMP_T_BIN;
-					smp->data.u.str.area = (char *)pos;
-					smp->data.u.str.data = elen;
-					smp->flags = SMP_F_VOL_TEST;
-					return 1;
-				}
-				break;
-			}
-
-			case PBUF_TYPE_32BIT:
-			{
-				if (!found) {
-					pos += sizeof(uint32_t);
-					left -= sizeof(uint32_t);
-				} else if (next_field == fid_sz - 1) {
-					smp->data.type = SMP_T_BIN;
-					smp->data.u.str.area = (char *)pos;
-					smp->data.u.str.data = sizeof(uint32_t);
-					smp->flags = SMP_F_VOL_TEST;
-					return 1;
-				}
-				break;
-			}
-
-			default:
-				return 0;
-			}
-
-			if ((ssize_t)(elen) > 0)
-				elen -= sleft - left;
-
-			if (found) {
-				next_field++;
-			}
-			else if ((ssize_t)elen <= 0) {
-				next_field = 0;
-			}
-		}
-		grpc_left -= grpc_msg_len;
-	}
-
-	return 0;
-}
-
 /* Fetch an HTTP header's IP value. takes a mandatory argument of type string
  * and an optional one of type int to designate a specific occurrence.
  * It returns an IPv4 or IPv6 address.
@@ -3122,7 +2882,6 @@
 	{ "req.hdr_ip",         smp_fetch_hdr_ip,             ARG2(0,STR,SINT), val_hdr, SMP_T_IPV4, SMP_USE_HRQHV },
 	{ "req.hdr_names",      smp_fetch_hdr_names,          ARG1(0,STR),      NULL,    SMP_T_STR,  SMP_USE_HRQHV },
 	{ "req.hdr_val",        smp_fetch_hdr_val,            ARG2(0,STR,SINT), val_hdr, SMP_T_SINT, SMP_USE_HRQHV },
-	{ "req.ungrpc",         smp_fetch_req_ungrpc,         ARG1(1, PBUF_FNUM), NULL,  SMP_T_BIN,  SMP_USE_HRQHV },
 
 	/* explicit req.{cook,hdr} are used to force the fetch direction to be response-only */
 	{ "res.cook",           smp_fetch_cookie,             ARG1(0,STR),      NULL,    SMP_T_STR,  SMP_USE_HRSHV },
diff --git a/src/sample.c b/src/sample.c
index 1f323bd..9c20469 100644
--- a/src/sample.c
+++ b/src/sample.c
@@ -2776,6 +2776,175 @@
 	return 1;
 }
 
+#define GRPC_MSG_COMPRESS_FLAG_SZ 1 /* 1 byte */
+#define GRPC_MSG_LENGTH_SZ        4 /* 4 bytes */
+#define GRPC_MSG_HEADER_SZ        (GRPC_MSG_COMPRESS_FLAG_SZ + GRPC_MSG_LENGTH_SZ)
+
+/*
+ * Extract the field value of an input binary sample. Takes a mandatory argument:
+ * the protocol buffers field identifier (dotted notation) internally represented
+ * as an array of unsigned integers and its size.
+ * Return 1 if the field was found, 0 if not.
+ */
+static int sample_conv_ungrpc(const struct arg *arg_p, struct sample *smp, void *private)
+{
+	unsigned char *pos;
+	size_t grpc_left;
+	unsigned int *fid;
+	size_t fid_sz;
+
+	if (!smp->strm)
+		return 0;
+
+	fid = arg_p[0].data.fid.ids;
+	fid_sz = arg_p[0].data.fid.sz;
+
+	pos = (unsigned char *)smp->data.u.str.area;
+	/* Remaining bytes in the body to be parsed. */
+	grpc_left = smp->data.u.str.data;
+
+	while (grpc_left > GRPC_MSG_COMPRESS_FLAG_SZ + GRPC_MSG_LENGTH_SZ) {
+		int next_field, found;
+		size_t grpc_msg_len, left;
+		unsigned int wire_type, field_number;
+		uint64_t key, elen;
+
+		grpc_msg_len = left = ntohl(*(uint32_t *)(pos + GRPC_MSG_COMPRESS_FLAG_SZ));
+
+		pos += GRPC_MSG_HEADER_SZ;
+		grpc_left -= GRPC_MSG_HEADER_SZ;
+
+		if (grpc_left < left)
+			return 0;
+
+		found = 1;
+		/* Length of the length-delimited messages if any. */
+		elen = 0;
+
+		/* Message decoding: there may be serveral key+value protobuf pairs by
+		 * gRPC message.
+		 */
+		next_field = 0;
+		while (next_field < fid_sz) {
+			uint64_t sleft;
+
+			if ((ssize_t)left <= 0)
+				return 0;
+
+			/* Remaining bytes saving. */
+			sleft = left;
+
+			/* Key decoding */
+			if (!protobuf_decode_varint(&key, &pos, &left))
+				return 0;
+
+			wire_type = key & 0x7;
+			field_number = key >> 3;
+			found = field_number == fid[next_field];
+
+			if (found && field_number != fid[next_field])
+				found = 0;
+
+			switch (wire_type) {
+			case PBUF_TYPE_VARINT:
+			{
+				if (!found) {
+					protobuf_skip_varint(&pos, &left);
+				} else if (next_field == fid_sz - 1) {
+					int varint_len;
+					unsigned char *spos = pos;
+
+					varint_len = protobuf_varint_getlen(&pos, &left);
+					if (varint_len == -1)
+						return 0;
+
+					smp->data.type = SMP_T_BIN;
+					smp->data.u.str.area = (char *)spos;
+					smp->data.u.str.data = varint_len;
+					smp->flags = SMP_F_VOL_TEST;
+					return 1;
+				}
+				break;
+			}
+
+			case PBUF_TYPE_64BIT:
+			{
+				if (!found) {
+					pos += sizeof(uint64_t);
+					left -= sizeof(uint64_t);
+				} else if (next_field == fid_sz - 1) {
+					smp->data.type = SMP_T_BIN;
+					smp->data.u.str.area = (char *)pos;
+					smp->data.u.str.data = sizeof(uint64_t);
+					smp->flags = SMP_F_VOL_TEST;
+					return 1;
+				}
+				break;
+			}
+
+			case PBUF_TYPE_LENGTH_DELIMITED:
+			{
+				/* Decode the length of this length-delimited field. */
+				if (!protobuf_decode_varint(&elen, &pos, &left))
+					return 0;
+
+				if (elen > left)
+					return 0;
+
+				/* The size of the current field is computed from here do skip
+				 * the bytes to encode the previous lenght.*
+				 */
+				sleft = left;
+				if (!found) {
+					/* Skip the current length-delimited field. */
+					pos += elen;
+					left -= elen;
+					break;
+				} else if (next_field == fid_sz - 1) {
+					smp->data.type = SMP_T_BIN;
+					smp->data.u.str.area = (char *)pos;
+					smp->data.u.str.data = elen;
+					smp->flags = SMP_F_VOL_TEST;
+					return 1;
+				}
+				break;
+			}
+
+			case PBUF_TYPE_32BIT:
+			{
+				if (!found) {
+					pos += sizeof(uint32_t);
+					left -= sizeof(uint32_t);
+				} else if (next_field == fid_sz - 1) {
+					smp->data.type = SMP_T_BIN;
+					smp->data.u.str.area = (char *)pos;
+					smp->data.u.str.data = sizeof(uint32_t);
+					smp->flags = SMP_F_VOL_TEST;
+					return 1;
+				}
+				break;
+			}
+
+			default:
+				return 0;
+			}
+
+			if ((ssize_t)(elen) > 0)
+				elen -= sleft - left;
+
+			if (found) {
+				next_field++;
+			}
+			else if ((ssize_t)elen <= 0) {
+				next_field = 0;
+			}
+		}
+		grpc_left -= grpc_msg_len;
+	}
+
+	return 0;
+}
+
 /* This function checks the "strcmp" converter's arguments and extracts the
  * variable name and its scope.
  */
@@ -3161,6 +3330,9 @@
 	{ "sha1",   sample_conv_sha1,      0,            NULL, SMP_T_BIN,  SMP_T_BIN  },
 	{ "concat", sample_conv_concat,    ARG3(1,STR,STR,STR), smp_check_concat, SMP_T_STR,  SMP_T_STR },
 	{ "strcmp", sample_conv_strcmp,    ARG1(1,STR), smp_check_strcmp, SMP_T_STR,  SMP_T_SINT },
+
+	/* gRPC converters. */
+	{ "ungrpc", sample_conv_ungrpc,    ARG1(1,PBUF_FNUM), NULL, SMP_T_BIN, SMP_T_BIN  },
 	{ "varint", sample_conv_varint,    0,            NULL, SMP_T_BIN,  SMP_T_SINT  },
 	{ "svarint", sample_conv_svarint,  0,            NULL, SMP_T_BIN,  SMP_T_SINT  },