take: add labels when CCAN_TAKE_DEBUG set, return in taken_any().

[ccan] / ccan / take / take.c

diff --git a/ccan/take/take.c b/ccan/take/take.c
index 73e5c29d206fcf5a5cf23e7b6f8d4836a3d06fc4..c628aac0dc97ff663db216e4f05a14b8cfd38bbf 100644 (file)
--- a/ccan/take/take.c
+++ b/ccan/take/take.c
@@ -1,16 +1,22 @@
 /* CC0 (Public domain) - see LICENSE file for details */
 #include <ccan/take/take.h>
 #include <ccan/likely/likely.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 static const void **takenarr;
+static const char **labelarr;
 static size_t max_taken, num_taken;
 static size_t allocfail;
 static void (*allocfailfn)(const void *p);
 
-void *take_(const void *p)
+void *take_(const void *p, const char *label)
 {
+       /* Overallocate: it's better than risking calloc returning NULL! */
+       if (unlikely(label && !labelarr))
+               labelarr = calloc(max_taken+1, sizeof(*labelarr));
+
        if (unlikely(num_taken == max_taken)) {
                const void **new;
 
@@ -25,9 +31,16 @@ void *take_(const void *p)
                        return (void *)p;
                }
                takenarr = new;
+               /* Once labelarr is set, we maintain it. */
+               if (labelarr)
+                       labelarr = realloc(labelarr,
+                                          sizeof(*labelarr) * (max_taken+1));
                max_taken++;
        }
+       if (unlikely(labelarr))
+               labelarr[num_taken] = label;
        takenarr[num_taken++] = p;
+
        return (void *)p;
 }
 
@@ -68,9 +81,23 @@ bool is_taken(const void *p)
        return find_taken(p) > 0;
 }
 
-bool taken_any(void)
+const char *taken_any(void)
 {
-       return num_taken != 0;
+       static char pointer_buf[32];
+
+       if (num_taken == 0)
+               return NULL;
+
+       /* We're *allowed* to have some with labels, some without. */
+       if (labelarr) {
+               size_t i;
+               for (i = 0; i < num_taken; i++)
+                       if (labelarr[i])
+                               return labelarr[i];
+       }
+
+       sprintf(pointer_buf, "%p", takenarr[0]);
+       return pointer_buf;
 }
 
 void take_cleanup(void)
@@ -78,6 +105,8 @@ void take_cleanup(void)
        max_taken = num_taken = 0;
        free(takenarr);
        takenarr = NULL;
+       free(labelarr);
+       labelarr = NULL;
 }
 
 void take_allocfail(void (*fn)(const void *p))