misc: expose handle print APIs

PR-URL: https://github.com/libuv/libuv/pull/291
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>

docs/src/misc.rst

@@ -288,3 +288,41 @@ API
     .. note::
         Not every platform can support nanosecond resolution; however, this value will always
         be in nanoseconds.
+
+.. c:function:: void uv_print_all_handles(uv_loop_t* loop, FILE* stream)
+
+    Prints all handles associated with the given `loop` to the given `stream`.
+
+    Example:
+
+    ::
+
+        uv_print_all_handles(uv_default_loop(), stderr);
+        /*
+        [--I] signal   0x1a25ea8
+        [-AI] async    0x1a25cf0
+        [R--] idle     0x1a7a8c8
+        */
+
+    The format is `[flags] handle-type handle-address`. For `flags`:
+
+    - `R` is printed for a handle that is referenced
+    - `A` is printed for a handle that is active
+    - `I` is printed for a handle that is internal
+
+    .. warning::
+        This function is meant for ad hoc debugging, there is no API/ABI
+        stability guarantees.
+
+    .. versionadded:: 1.8.0
+
+.. c:function:: void uv_print_active_handles(uv_loop_t* loop, FILE* stream)
+
+    This is the same as :c:func:`uv_print_all_handles` except only active handles
+    are printed.
+
+    .. warning::
+        This function is meant for ad hoc debugging, there is no API/ABI
+        stability guarantees.
+
+    .. versionadded:: 1.8.0

include/uv.h

@@ -424,6 +424,10 @@ UV_EXTERN int uv_is_active(const uv_handle_t* handle);
 
 UV_EXTERN void uv_walk(uv_loop_t* loop, uv_walk_cb walk_cb, void* arg);
 
+/* Helpers for ad hoc debugging, no API/ABI stability guaranteed. */
+UV_EXTERN void uv_print_all_handles(uv_loop_t* loop, FILE* stream);
+UV_EXTERN void uv_print_active_handles(uv_loop_t* loop, FILE* stream);
+
 UV_EXTERN void uv_close(uv_handle_t* handle, uv_close_cb close_cb);
 
 UV_EXTERN int uv_send_buffer_size(uv_handle_t* handle, int* value);

src/uv-common.c

@@ -355,8 +355,7 @@ void uv_walk(uv_loop_t* loop, uv_walk_cb walk_cb, void* arg) {
 }
 
 
-#ifndef NDEBUG
+static void uv__print_handles(uv_loop_t* loop, int only_active, FILE* stream) {
-static void uv__print_handles(uv_loop_t* loop, int only_active) {
   const char* type;
   QUEUE* q;
   uv_handle_t* h;
@@ -377,7 +376,7 @@ static void uv__print_handles(uv_loop_t* loop, int only_active) {
       default: type = "<unknown>";
     }
 
-    fprintf(stderr,
+    fprintf(stream,
             "[%c%c%c] %-8s %p\n",
             "R-"[!(h->flags & UV__HANDLE_REF)],
             "A-"[!(h->flags & UV__HANDLE_ACTIVE)],
@@ -388,15 +387,14 @@ static void uv__print_handles(uv_loop_t* loop, int only_active) {
 }
 
 
-void uv_print_all_handles(uv_loop_t* loop) {
+void uv_print_all_handles(uv_loop_t* loop, FILE* stream) {
-  uv__print_handles(loop, 0);
+  uv__print_handles(loop, 0, stream);
 }
 
 
-void uv_print_active_handles(uv_loop_t* loop) {
+void uv_print_active_handles(uv_loop_t* loop, FILE* stream) {
-  uv__print_handles(loop, 1);
+  uv__print_handles(loop, 1, stream);
 }
-#endif
 
 
 void uv_ref(uv_handle_t* handle) {