tal: add tal_dup_or_null and tal_dup_talarr helpers.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/ccan/tal/tal.c b/ccan/tal/tal.c
index 05d52e1dbe5cab4409461c42b2c26ed57b009987..061fc2907aff4cb5e67e8863c04a25233b9e5ea7 100644 (file)
--- a/ccan/tal/tal.c
+++ b/ccan/tal/tal.c
@@ -767,11 +767,17 @@ out:
 }
 
 void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
-              size_t n, size_t extra, const char *label)
+              size_t n, size_t extra, bool nullok, const char *label)
 {
        void *ret;
        size_t nbytes = size;
 
+       if (nullok && p == NULL) {
+               /* take(NULL) works. */
+               (void)taken(p);
+               return NULL;
+       }
+       
        if (!adjust_size(&nbytes, n)) {
                if (taken(p))
                        tal_free(p);
@@ -802,6 +808,11 @@ void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
        return ret;
 }
 
+void *tal_dup_talarr_(const tal_t *ctx, const tal_t *src TAKES, const char *label)
+{
+       return tal_dup_(ctx, src, 1, tal_bytelen(src), 0, true, label);
+}
+
 void tal_set_backend(void *(*alloc_fn)(size_t size),
                     void *(*resize_fn)(void *, size_t size),
                     void (*free_fn)(void *),

diff --git a/ccan/tal/tal.h b/ccan/tal/tal.h
index a3a1549153fe4f42636b116d33162c774982df46..c486f9e8e194a99b51ffdb8117788bbae86a89ed 100644 (file)
--- a/ccan/tal/tal.h
+++ b/ccan/tal/tal.h
@@ -352,10 +352,21 @@ tal_t *tal_parent(const tal_t *ctx);
  * tal_dup - duplicate an object.
  * @ctx: The tal allocated object to be parent of the result (may be NULL).
  * @type: the type (should match type of @p!)
- * @p: the object to copy (or reparented if take())
+ * @p: the object to copy (or reparented if take()).  Must not be NULL.
  */
 #define tal_dup(ctx, type, p)                                  \
-       tal_dup_label(ctx, type, p, TAL_LABEL(type, ""))
+       tal_dup_label(ctx, type, p, TAL_LABEL(type, ""), false)
+
+/**
+ * tal_dup_or_null - duplicate an object, or just pass NULL.
+ * @ctx: The tal allocated object to be parent of the result (may be NULL).
+ * @type: the type (should match type of @p!)
+ * @p: the object to copy (or reparented if take())
+ *
+ * if @p is NULL, just return NULL, otherwise to tal_dup().
+ */
+#define tal_dup_or_null(ctx, type, p)                                  \
+       tal_dup_label(ctx, type, p, TAL_LABEL(type, ""), true)
 
 /**
  * tal_dup_arr - duplicate an array.
@@ -369,7 +380,17 @@ tal_t *tal_parent(const tal_t *ctx);
        tal_dup_arr_label(ctx, type, p, n, extra, TAL_LABEL(type, "[]"))
 
 
-
+/**
+ * tal_dup_arr - duplicate a tal array.
+ * @ctx: The tal allocated object to be parent of the result (may be NULL).
+ * @type: the type (should match type of @p!)
+ * @p: the tal array to copy (or resized & reparented if take())
+ *
+ * The comon case of duplicating an entire tal array.
+ */
+#define tal_dup_talarr(ctx, type, p)                                   \
+       ((type *)tal_dup_talarr_((ctx), tal_typechk_(p, type *),        \
+                                TAL_LABEL(type, "[]")))
 /* Lower-level interfaces, where you want to supply your own label string. */
 #define tal_label(ctx, type, label)                                            \
        ((type *)tal_alloc_((ctx), sizeof(type), false, label))
@@ -379,13 +400,13 @@ tal_t *tal_parent(const tal_t *ctx);
        ((type *)tal_alloc_arr_((ctx), sizeof(type), (count), false, label))
 #define tal_arrz_label(ctx, type, count, label)                                        \
        ((type *)tal_alloc_arr_((ctx), sizeof(type), (count), true, label))
-#define tal_dup_label(ctx, type, p, label)                     \
+#define tal_dup_label(ctx, type, p, label, nullok)                     \
        ((type *)tal_dup_((ctx), tal_typechk_(p, type *),       \
-                         sizeof(type), 1, 0,                   \
+                         sizeof(type), 1, 0, nullok,           \
                          label))
 #define tal_dup_arr_label(ctx, type, p, n, extra, label)       \
        ((type *)tal_dup_((ctx), tal_typechk_(p, type *),       \
-                         sizeof(type), (n), (extra),           \
+                         sizeof(type), (n), (extra), false,    \
                          label))
 
 /**
@@ -505,7 +526,9 @@ void *tal_alloc_arr_(const tal_t *ctx, size_t bytes, size_t count, bool clear,
                     const char *label);
 
 void *tal_dup_(const tal_t *ctx, const void *p TAKES, size_t size,
-              size_t n, size_t extra, const char *label);
+              size_t n, size_t extra, bool nullok, const char *label);
+void *tal_dup_talarr_(const tal_t *ctx, const tal_t *src TAKES,
+                     const char *label);
 
 tal_t *tal_steal_(const tal_t *new_parent, const tal_t *t);