Change amqp_error_string() to ret static strings

This is an API/ABI break.

5 files changed, 86 insertions, 43 deletions

diff --git a/examples/utils.c b/examples/utils.c
index 4b00470..5d4a1f9 100644
--- a/examples/utils.c
+++ b/examples/utils.c
@@ -59,9 +59,7 @@ void die(const char *fmt, ...)
 void die_on_error(int x, char const *context)
 {
   if (x < 0) {
-    char *errstr = amqp_error_string(-x);
-    fprintf(stderr, "%s: %s\n", context, errstr);
-    free(errstr);
+    fprintf(stderr, "%s: %s\n", context, amqp_error_string(x));
     exit(1);
   }
 }
diff --git a/librabbitmq/amqp.h b/librabbitmq/amqp.h
index 0388bd1..2a0bf19 100644
--- a/librabbitmq/amqp.h
+++ b/librabbitmq/amqp.h
@@ -588,11 +588,10 @@ AMQP_CALL amqp_data_in_buffer(amqp_connection_state_t state);
 /*
  * Get the error string for the given error code.
  *
- * The returned string resides on the heap; the caller is responsible
- * for freeing it.
+ * Error string is statically allocated. (API changed in v0.4.0)
  */
 AMQP_PUBLIC_FUNCTION
-char *
+const char *
 AMQP_CALL amqp_error_string(int err);
 
 AMQP_PUBLIC_FUNCTION
diff --git a/librabbitmq/amqp_api.c b/librabbitmq/amqp_api.c
index cab0f4b..9f65c4c 100644
--- a/librabbitmq/amqp_api.c
+++ b/librabbitmq/amqp_api.c
@@ -46,34 +46,84 @@
 #include <stdlib.h>
 #include <string.h>
 
-static const char *client_error_strings[] = {
-  "operation completed successfully",   /* AMQP_STATUS_OK */
-  "could not allocate memory",          /* AMQP_STATUS_NO_MEMORY */
-  "received bad AMQP data",             /* AMQP_STATUS_BAD_AQMP_DATA */
-  "unknown AMQP class id",              /* AMQP_STATUS_UNKNOWN_CLASS */
-  "unknown AMQP method id",             /* AMQP_STATUS_UNKNOWN_METHOD */
-  "hostname lookup failed",             /* AMQP_STATUS_GETHOSTBYNAME_FAILED */
-  "incompatible AMQP version",          /* AMQP_STATUS_INCOMPATIBLE_AMQP_VERSION */
-  "connection closed unexpectedly",     /* AMQP_STATUS_CONNECTION_CLOSED */
-  "could not parse AMQP URL",           /* AMQP_STATUS_BAD_AMQP_URL */
-  "a socket error occurred",            /* AMQP_STATUS_SOCKET_ERROR */
-  "a SSL error occurred"                /* AMQP_STATUS_SSL_ERROR */
+#define ERROR_MASK (0x00FF)
+#define ERROR_CATEGORY_MASK (0xFF00)
+
+enum error_category_enum_ {
+  EC_base = 0,
+  EC_tcp = 1,
+  EC_ssl = 2
+};
+
+static const char *base_error_strings[] = {
+  "operation completed successfully",   /* AMQP_STATUS_OK                       0x0 */
+  "could not allocate memory",          /* AMQP_STATUS_NO_MEMORY                -0x0001 */
+  "invalid AMQP data",                  /* AMQP_STATUS_BAD_AQMP_DATA            -0x0002 */
+  "unknown AMQP class id",              /* AMQP_STATUS_UNKNOWN_CLASS            -0x0003 */
+  "unknown AMQP method id",             /* AMQP_STATUS_UNKNOWN_METHOD           -0x0004 */
+  "hostname lookup failed",             /* AMQP_STATUS_HOSTNAME_RESOLUTION_FAILED -0x0005 */
+  "incompatible AMQP version",          /* AMQP_STATUS_INCOMPATIBLE_AMQP_VERSION -0x0006 */
+  "connection closed unexpectedly",     /* AMQP_STATUS_CONNECTION_CLOSED        -0x0007 */
+  "could not parse AMQP URL",           /* AMQP_STATUS_BAD_AMQP_URL             -0x0008 */
+  "a socket error occurred",            /* AMQP_STATUS_SOCKET_ERROR             -0x0009 */
+  "invalid parameter",                  /* AMQP_STATUS_INVALID_PARAMETER        -0x000A */
+  "table too large for buffer",         /* AMQP_STATUS_TABLE_TOO_BIG            -0x000B */
+  "unexpected method received"          /* AMQP_STATUS_WRONG_METHOD             -0x000C */
+};
+
+static const char *tcp_error_strings[] = {
+  "a socket error occurred",              /* AMQP_STATUS_TCP_ERROR                -0x0100 */
+  "socket library initialization failed"  /* AMQP_STATUS_TCP_SOCKETLIB_INIT_ERROR -0x0101 */
+};
+
+static const char *ssl_error_strings[] = {
+  "a SSL error occurred",                 /* AMQP_STATUS_SSL_ERROR                -0x0200 */
+  "SSL hostname verification failed",     /* AMQP_STATUS_SSL_HOSTNAME_VERIFY_FAILED -0x0201 */
+  "SSL peer cert verification failed",    /* AMQP_STATUS_SSL_PEER_VERIFY_FAILED -0x0202 */
+  "SSL handshake failed"                  /* AMQP_STATUS_SSL_CONNECTION_FAILED  -0x0203 */
 };
 
-char *amqp_error_string(int err)
+static const char *unknown_error_string = "(unknown error)";
+
+const char *amqp_error_string(int code)
 {
-  const char *str;
-  const int max_error_index = sizeof(client_error_strings) / sizeof(char *);
+  const char *error_string;
+  size_t category = (((-code) & ERROR_CATEGORY_MASK) >> 16);
+  size_t error = (-code) & ERROR_MASK;
+
+  switch (category) {
+    case EC_base:
+      if (error < (sizeof(base_error_strings) / sizeof(char *))) {
+        error_string = base_error_strings[error];
+      } else {
+        error_string = unknown_error_string;
+      }
+      break;
+
+    case EC_tcp:
+      if (error < (sizeof(tcp_error_strings) / sizeof(char *))) {
+        error_string = tcp_error_strings[error];
+      } else {
+        error_string = unknown_error_string;
+      }
+      break;
+
+    case EC_ssl:
+      if (error < (sizeof(ssl_error_strings) / sizeof(char *))) {
+        error_string = ssl_error_strings[error];
+      } else {
+        error_string = unknown_error_string;
+      }
 
-  err = -err;
+      break;
+
+    default:
+      error_string = unknown_error_string;
+      break;
 
-  if (err < 0 || err > max_error_index) {
-    str = "an unknown error occurred";
-  } else {
-    str = client_error_strings[err];
   }
 
-  return strdup(str);
+  return error_string;
 }
 
 void amqp_abort(const char *fmt, ...)
diff --git a/tools/common.c b/tools/common.c
index 0c61d16..b556988 100644
--- a/tools/common.c
+++ b/tools/common.c
@@ -83,7 +83,6 @@ void die_errno(int err, const char *fmt, ...)
 void die_amqp_error(int err, const char *fmt, ...)
 {
   va_list ap;
-  char *errstr;
 
   if (err >= 0) {
     return;
@@ -92,21 +91,20 @@ void die_amqp_error(int err, const char *fmt, ...)
   va_start(ap, fmt);
   vfprintf(stderr, fmt, ap);
   va_end(ap);
-  fprintf(stderr, ": %s\n", errstr = amqp_error_string(-err));
-  free(errstr);
+  fprintf(stderr, ": %s\n", amqp_error_string(err));
   exit(1);
 }
 
-char *amqp_server_exception_string(amqp_rpc_reply_t r)
+const char *amqp_server_exception_string(amqp_rpc_reply_t r)
 {
   int res;
-  char *s;
+  static char s[512];
 
   switch (r.reply.id) {
   case AMQP_CONNECTION_CLOSE_METHOD: {
     amqp_connection_close_t *m
       = (amqp_connection_close_t *)r.reply.decoded;
-    res = asprintf(&s, "server connection error %d, message: %.*s",
+    res = snprintf(s, sizeof(s), "server connection error %d, message: %.*s",
                    m->reply_code,
                    (int)m->reply_text.len,
                    (char *)m->reply_text.bytes);
@@ -116,7 +114,7 @@ char *amqp_server_exception_string(amqp_rpc_reply_t r)
   case AMQP_CHANNEL_CLOSE_METHOD: {
     amqp_channel_close_t *m
       = (amqp_channel_close_t *)r.reply.decoded;
-    res = asprintf(&s, "server channel error %d, message: %.*s",
+    res = snprintf(s, sizeof(s), "server channel error %d, message: %.*s",
                    m->reply_code,
                    (int)m->reply_text.len,
                    (char *)m->reply_text.bytes);
@@ -124,7 +122,7 @@ char *amqp_server_exception_string(amqp_rpc_reply_t r)
   }
 
   default:
-    res = asprintf(&s, "unknown server error, method id 0x%08X",
+    res = snprintf(s, sizeof(s), "unknown server error, method id 0x%08X",
                    r.reply.id);
     break;
   }
@@ -132,14 +130,14 @@ 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)
 {
   switch (r.reply_type) {
   case AMQP_RESPONSE_NORMAL:
-    return strdup("normal response");
+    return "normal response";
 
   case AMQP_RESPONSE_NONE:
-    return strdup("missing RPC reply type");
+    return "missing RPC reply type";
 
   case AMQP_RESPONSE_LIBRARY_EXCEPTION:
     return amqp_error_string(r.library_error);
@@ -155,7 +153,6 @@ char *amqp_rpc_reply_string(amqp_rpc_reply_t r)
 void die_rpc(amqp_rpc_reply_t r, const char *fmt, ...)
 {
   va_list ap;
-  char *errstr;
 
   if (r.reply_type == AMQP_RESPONSE_NORMAL) {
     return;
@@ -164,8 +161,7 @@ void die_rpc(amqp_rpc_reply_t r, const char *fmt, ...)
   va_start(ap, fmt);
   vfprintf(stderr, fmt, ap);
   va_end(ap);
-  fprintf(stderr, ": %s\n", errstr = amqp_rpc_reply_string(r));
-  free(errstr);
+  fprintf(stderr, ": %s\n", amqp_rpc_reply_string(r));
   exit(1);
 }
 
diff --git a/tools/common.h b/tools/common.h
index cc186ec..7d01966 100644
--- a/tools/common.h
+++ b/tools/common.h
@@ -41,8 +41,8 @@
 #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)));