Make error codes returned by librabbitmq functions opaque

Windows doesn't generally use POSIX error codes, which poses a problem
for librabbitmq's approach of using those error codes in its API.  So
make the librabbitmq error codes opaque: They are still be integers,
but client code is not supposed to assume anything about them, except
that they can be passed to a new amqp_error_string() function which
returns the corresponding error message

Internally, the error codes are either taken from a set of
librabbitmq-specific values, or correspond to an OS-specific (POSIX or
win32) error code, with a simple encoding to indicate which is which.

4 files changed, 33 insertions, 38 deletions

diff --git a/tools/common.c b/tools/common.c
index d4771ac..ec24085 100644
--- a/tools/common.c
+++ b/tools/common.c
@@ -84,11 +84,24 @@ void die_errno(int err, const char *fmt, ...)
 	va_start(ap, fmt);
 	vfprintf(stderr, fmt, ap);
 	va_end(ap);
-	fprintf(stderr, ": %s\n", strerror(err));
+	fprintf(stderr, ": %s\n", strerror(errno));
 	exit(1);
 }
 
-char *amqp_server_exception_string(amqp_rpc_reply_t r)
+void die_amqp_error(int err, const char *fmt, ...)
+{
+	if (err <= 0)
+		return;
+	
+	va_list ap;
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	fprintf(stderr, ": %s\n", amqp_error_string(err));
+	exit(1);
+}
+
+const char *amqp_server_exception_string(amqp_rpc_reply_t r)
 {
 	int res;
 	char *s;
@@ -123,26 +136,17 @@ char *amqp_server_exception_string(amqp_rpc_reply_t r)
 	return res >= 0 ? s : NULL;
 }
 
-char *amqp_rpc_reply_string(amqp_rpc_reply_t r)
+const char *amqp_rpc_reply_string(amqp_rpc_reply_t r)
 {
-	const char *s;
-
 	switch (r.reply_type) {
 	case AMQP_RESPONSE_NORMAL:
-		s = "normal response";
-		break;
+		return strdup("normal response");
 		
 	case AMQP_RESPONSE_NONE:
-		s = "missing RPC reply type";
-		break;
+		return strdup("missing RPC reply type");
 
 	case AMQP_RESPONSE_LIBRARY_EXCEPTION:
-		if (r.library_errno)
-			s = strerror(r.library_errno);
-		else
-			s = "end of stream";
-
-		break;
+		return amqp_error_string(r.library_error);
 
 	case AMQP_RESPONSE_SERVER_EXCEPTION:
 		return amqp_server_exception_string(r);
@@ -150,8 +154,6 @@ char *amqp_rpc_reply_string(amqp_rpc_reply_t r)
 	default:
 		abort();
 	}
-
-	return strdup(s);
 }
 
 void die_rpc(amqp_rpc_reply_t r, const char *fmt, ...)
@@ -220,13 +222,8 @@ amqp_connection_state_t make_connection(void)
 	}
 
 	s = amqp_open_socket(host, port ? port : 5672);
-	if (s < 0) {
-		if (s == -ENOENT)
-			die("unknown host %s", host);
-		else
-			die_errno(-s, "opening socket to %s", amqp_server);
-	}
-
+	die_amqp_error(-s, "opening socket to %s", amqp_server);
+	
 	set_cloexec(s);
 	
 	conn = amqp_new_connection();
@@ -252,8 +249,7 @@ void close_connection(amqp_connection_state_t conn)
 		"closing connection");
 	
 	res = amqp_end_connection(conn);
-	if (res < 0)
-		die_errno(-res, "closing connection");
+	die_amqp_error(-res, "closing connection");
 }
 
 amqp_bytes_t read_all(int fd)
@@ -304,8 +300,7 @@ void copy_body(amqp_connection_state_t conn, int fd)
 	amqp_frame_t frame;
 		
 	int res = amqp_simple_wait_frame(conn, &frame);
-	if (res < 0)
-		die_errno(-res, "waiting for header frame");
+	die_amqp_error(-res, "waiting for header frame");
 	if (frame.frame_type != AMQP_FRAME_HEADER)
 		die("expected header, got frame type 0x%X",
 		    frame.frame_type);
@@ -313,8 +308,7 @@ void copy_body(amqp_connection_state_t conn, int fd)
 	body_remaining = frame.payload.properties.body_size;
 	while (body_remaining) {
 		res = amqp_simple_wait_frame(conn, &frame);
-		if (res < 0)
-			die_errno(-res, "waiting for body frame");
+		die_amqp_error(-res, "waiting for body frame");
 		if (frame.frame_type != AMQP_FRAME_BODY)
 			die("expected body, got frame type 0x%X",
 			    frame.frame_type);
diff --git a/tools/common.h b/tools/common.h
index 8ea754c..b3d8ab9 100644
--- a/tools/common.h
+++ b/tools/common.h
@@ -55,13 +55,15 @@
 #include <amqp.h>
 #include <amqp_framing.h>
 
-extern char *amqp_server_exception_string(amqp_rpc_reply_t r);
-extern char *amqp_rpc_reply_string(amqp_rpc_reply_t r);
+extern const char *amqp_server_exception_string(amqp_rpc_reply_t r);
+extern const char *amqp_rpc_reply_string(amqp_rpc_reply_t r);
 
 extern void die(const char *fmt, ...)
 	__attribute__ ((format (printf, 1, 2)));
 extern void die_errno(int err, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3)));
+extern void die_amqp_error(int err, const char *fmt, ...)
+	__attribute__ ((format (printf, 2, 3)));
 extern void die_rpc(amqp_rpc_reply_t r, const char *fmt, ...)
 	__attribute__ ((format (printf, 2, 3)));
 
diff --git a/tools/consume.c b/tools/consume.c
index b6bd5e2..9999960 100644
--- a/tools/consume.c
+++ b/tools/consume.c
@@ -155,8 +155,7 @@ static void do_consume(amqp_connection_state_t conn, amqp_bytes_t queue,
 		struct pipeline pl;
 		uint64_t delivery_tag;
 		int res = amqp_simple_wait_frame(conn, &frame);
-		if (res < 0)
-			die_errno(-res, "waiting for header frame");
+		die_amqp_error(res, "waiting for header frame");
 
 		if (frame.frame_type != AMQP_FRAME_METHOD
 		    || frame.payload.method.id != AMQP_BASIC_DELIVER_METHOD)
@@ -170,8 +169,9 @@ static void do_consume(amqp_connection_state_t conn, amqp_bytes_t queue,
 		copy_body(conn, pl.infd);
 
 		if (finish_pipeline(&pl) && !no_ack)
-			die_errno(-amqp_basic_ack(conn, 1, delivery_tag, 0),
-				  "basic.ack");
+			die_amqp_error(amqp_basic_ack(conn, 1, delivery_tag,
+						      0),
+				       "basic.ack");
 
 		amqp_maybe_release_buffers(conn);
 	}
diff --git a/tools/publish.c b/tools/publish.c
index 15d2386..0917dae 100644
--- a/tools/publish.c
+++ b/tools/publish.c
@@ -64,8 +64,7 @@ static void do_publish(amqp_connection_state_t conn,
 				     cstring_bytes(exchange),
 				     cstring_bytes(routing_key),
 				     0, 0, props, body);
-	if (res != 0)
-		die_errno(-res, "basic.publish");
+	die_amqp_error(res, "basic.publish");
 }
 
 int main(int argc, const char **argv)