error reporting: return sensible messages for synthetic errors

src/unix/error.c

@@ -56,8 +56,28 @@ void uv_fatal_error(const int errorno, const char* syscall) {
 }
 
 
-char* uv_strerror(uv_err_t err) {
+static int uv__translate_lib_error(int code) {
-  return strerror(err.sys_errno_);
+  switch (code) {
+    case UV_ENOENT: return ENOENT;
+    case UV_EACCESS: return EACCES;
+    case UV_EBADF: return EBADF;
+    case UV_EPIPE: return EPIPE;
+    case UV_EAGAIN: return EAGAIN;
+    case UV_ECONNRESET: return ECONNRESET;
+    case UV_EFAULT: return EFAULT;
+    case UV_EMFILE: return EMFILE;
+    case UV_EMSGSIZE: return EMSGSIZE;
+    case UV_EINVAL: return EINVAL;
+    case UV_ECONNREFUSED: return ECONNREFUSED;
+    case UV_EADDRINUSE: return EADDRINUSE;
+    case UV_EADDRNOTAVAIL: return EADDRNOTAVAIL;
+    case UV_ENOTCONN: return ENOTCONN;
+    case UV_EEXIST: return EEXIST;
+    default: return -1;
+  }
+
+  assert(0 && "unreachable");
+  return -1;
 }
 
 
@@ -85,3 +105,22 @@ uv_err_code uv_translate_sys_error(int sys_errno) {
   assert(0 && "unreachable");
   return -1;
 }
+
+
+/* TODO Pull in error messages so we don't have to
+ *  a) rely on what the system provides us
+ *  b) reverse-map the error codes
+ */
+char* uv_strerror(uv_err_t err) {
+  int errorno;
+
+  if (err.sys_errno_)
+    errorno = err.sys_errno_;
+  else
+    errorno = uv__translate_lib_error(err.code);
+
+  if (errorno == -1)
+    return "Unknown error";
+  else
+    return strerror(errorno);
+}

test/test-error.c

@@ -0,0 +1,59 @@
+/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "uv.h"
+#include "task.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+/*
+ * Synthetic errors (errors that originate from within libuv, not the system)
+ * should produce sensible error messages when run through uv_strerror().
+ *
+ * See https://github.com/joyent/libuv/issues/210
+ */
+TEST_IMPL(error_message) {
+  uv_err_t e;
+
+  /* Cop out. Can't do proper checks on systems with
+   * i18n-ized error messages...
+   */
+  e.code = 0, e.sys_errno_ = 0;
+
+  if (strcmp(uv_strerror(e), "Success") != 0) {
+    printf("i18n error messages detected, skipping test.\n");
+    return 0;
+  }
+
+  e.code = UV_EINVAL, e.sys_errno_ = 0;
+  ASSERT(strstr(uv_strerror(e), "Success") == NULL);
+
+  e.code = UV_UNKNOWN, e.sys_errno_ = 0;
+  ASSERT(strcmp(uv_strerror(e), "Unknown error") == 0);
+
+  e.code = 1337, e.sys_errno_ = 0;
+  ASSERT(strcmp(uv_strerror(e), "Unknown error") == 0);
+
+  return 0;
+}

test/test-list.h

@@ -53,6 +53,7 @@ TEST_DECLARE   (connection_fail)
 TEST_DECLARE   (connection_fail_doesnt_auto_close)
 TEST_DECLARE   (shutdown_eof)
 TEST_DECLARE   (callback_stack)
+TEST_DECLARE   (error_message)
 TEST_DECLARE   (timer)
 TEST_DECLARE   (timer_ref)
 TEST_DECLARE   (timer_ref2)
@@ -166,6 +167,8 @@ TASK_LIST_START
   TEST_ENTRY  (callback_stack)
   TEST_HELPER (callback_stack, tcp4_echo_server)
 
+  TEST_ENTRY  (error_message)
+
   TEST_ENTRY  (timer)
   TEST_ENTRY  (timer_ref)
   TEST_ENTRY  (timer_ref2)

uv.gyp

@@ -247,6 +247,7 @@
         'test/test-get-loadavg.c',
         'test/task.h',
         'test/test-async.c',
+        'test/test-error.c',
         'test/test-callback-stack.c',
         'test/test-connection-fail.c',
         'test/test-delayed-accept.c',