From 5ad7fc306e8a6fb18222a502b8881f39384c4076 Mon Sep 17 00:00:00 2001
From: Tony Garnock-Jones <tonyg@kcbbs.gen.nz>
Date: Thu, 30 Apr 2009 00:07:05 +0100
Subject: Avoid leaking memory by being precise about when a delivery is
 finished, which lets us recycle a connection's memory pool at exactly the
 right time.

---
 examples/amqp_listen.c | 97 +++++++++++++++++++++++++++++++-------------------
 1 file changed, 60 insertions(+), 37 deletions(-)

(limited to 'examples')

diff --git a/examples/amqp_listen.c b/examples/amqp_listen.c
index e33b3ef..f759183 100644
--- a/examples/amqp_listen.c
+++ b/examples/amqp_listen.c
@@ -8,6 +8,7 @@
 #include <amqp_framing.h>
 
 #include <unistd.h>
+#include <assert.h>
 
 #include "example_utils.h"
 
@@ -100,53 +101,75 @@ int main(int argc, char const * const *argv) {
     amqp_frame_t frame;
     int result;
 
+    amqp_basic_deliver_t *d;
+    amqp_basic_properties_t *p;
+    size_t body_target;
+    size_t body_received;
+
     while (1) {
       amqp_maybe_release_buffers(conn);
       result = amqp_simple_wait_frame(conn, &frame);
       printf("Result %d\n", result);
-      if (result <= 0) goto shutdown;
+      if (result <= 0)
+	break;
 
-    analyse_frame:
       printf("Frame type %d, channel %d\n", frame.frame_type, frame.channel);
-      if (frame.frame_type == AMQP_FRAME_METHOD) {
-	printf("Method %s\n", amqp_method_name(frame.payload.method.id));
-	if (frame.payload.method.id == AMQP_BASIC_DELIVER_METHOD) {
-	  amqp_basic_deliver_t *d = (amqp_basic_deliver_t *) frame.payload.method.decoded;
-	  amqp_basic_properties_t *p;
-	  printf("Delivery %llu, exchange %.*s routingkey %.*s\n",
-		 d->delivery_tag,
-		 (int) d->exchange.len, (char *) d->exchange.bytes,
-		 (int) d->routing_key.len, (char *) d->routing_key.bytes);
-
-	  result = amqp_simple_wait_frame(conn, &frame);
-	  if (result <= 0) goto shutdown;
-	  if (frame.frame_type != AMQP_FRAME_HEADER) {
-	    fprintf(stderr, "Expected header!");
-	    abort();
-	  }
-	  p = (amqp_basic_properties_t *) frame.payload.properties.decoded;
-	  if (p->_flags & AMQP_BASIC_CONTENT_TYPE_FLAG) {
-	    printf("Content-type: %.*s\n",
-		   (int) p->content_type.len, (char *) p->content_type.bytes);
-	  }
-	  printf("----\n");
-
-	  while (1) {
-	    result = amqp_simple_wait_frame(conn, &frame);
-	    if (result <= 0) goto shutdown;
-	    if (frame.frame_type != AMQP_FRAME_BODY) {
-	      printf("====\n");
-	      goto analyse_frame;
-	    }
-	    amqp_dump(frame.payload.body_fragment.bytes,
-		      frame.payload.body_fragment.len);
-	  }
-	}
+      if (frame.frame_type != AMQP_FRAME_METHOD)
+	continue;
+
+      printf("Method %s\n", amqp_method_name(frame.payload.method.id));
+      if (frame.payload.method.id != AMQP_BASIC_DELIVER_METHOD)
+	continue;
+
+      d = (amqp_basic_deliver_t *) frame.payload.method.decoded;
+      printf("Delivery %llu, exchange %.*s routingkey %.*s\n",
+	     d->delivery_tag,
+	     (int) d->exchange.len, (char *) d->exchange.bytes,
+	     (int) d->routing_key.len, (char *) d->routing_key.bytes);
+
+      result = amqp_simple_wait_frame(conn, &frame);
+      if (result <= 0)
+	break;
+
+      if (frame.frame_type != AMQP_FRAME_HEADER) {
+	fprintf(stderr, "Expected header!");
+	abort();
+      }
+      p = (amqp_basic_properties_t *) frame.payload.properties.decoded;
+      if (p->_flags & AMQP_BASIC_CONTENT_TYPE_FLAG) {
+	printf("Content-type: %.*s\n",
+	       (int) p->content_type.len, (char *) p->content_type.bytes);
+      }
+      printf("----\n");
+
+      body_target = frame.payload.properties.body_size;
+      body_received = 0;
+
+      while (body_received < body_target) {
+	result = amqp_simple_wait_frame(conn, &frame);
+	if (result <= 0)
+	  break;
+
+	if (frame.frame_type != AMQP_FRAME_BODY) {
+	  fprintf(stderr, "Expected body!");
+	  abort();
+	}	  
+
+	body_received += frame.payload.body_fragment.len;
+	assert(body_received <= body_target);
+
+	amqp_dump(frame.payload.body_fragment.bytes,
+		  frame.payload.body_fragment.len);
+      }
+
+      if (body_received != body_target) {
+	/* Can only happen when amqp_simple_wait_frame returns <= 0 */
+	/* We break here to close the connection */
+	break;
       }
     }
   }
 
- shutdown:
   die_on_amqp_error(amqp_channel_close(conn, AMQP_REPLY_SUCCESS), "Closing channel");
   die_on_amqp_error(amqp_connection_close(conn, AMQP_REPLY_SUCCESS), "Closing connection");
   amqp_destroy_connection(conn);
-- 
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