utils: tal_hexstr() helper.

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

Makefile

@@ -45,6 +45,7 @@ CORE_SRC :=					\
 	permute_tx.c				\
 	protobuf_convert.c			\
 	remove_dust.c				\
+	utils.c					\
 	version.c
 CORE_OBJS := $(CORE_SRC:.c=.o)
 
@@ -156,6 +157,7 @@ CORE_HEADERS := close_tx.h			\
 	remove_dust.h				\
 	state.h					\
 	state_types.h				\
+	utils.h					\
 	version.h
 
 GEN_HEADERS := 	gen_state_names.h		\

bitcoin/test/run-tx-encode.c

@@ -1,6 +1,7 @@
 #include "bitcoin/tx.c"
 #include "bitcoin/shadouble.c"
 #include "bitcoin/varint.c"
+#include "utils.c"
 #include <assert.h>
 #include <ccan/str/hex/hex.h>
 
@@ -8,8 +9,7 @@ const char extended_tx[] = "02000000000101b5bef485c41d0d1f58d1e8a561924ece5c476d
 
 static void hexeq(const void *p, size_t len, const char *hex)
 {
-	char *tmphex = tal_arr(NULL, char, hex_str_size(len));
-	hex_encode(p, len, tmphex, tal_count(tmphex));
+	char *tmphex = tal_hexstr(NULL, p, len);
 
 	if (strcmp(hex, tmphex)) {
 		fprintf(stderr, "Expected '%s' got '%s'", hex, tmphex);

daemon/bitcoind.c

@@ -7,6 +7,7 @@
 #include "json.h"
 #include "lightningd.h"
 #include "log.h"
+#include "utils.h"
 #include <ccan/cast/cast.h>
 #include <ccan/io/io.h>
 #include <ccan/pipecmd/pipecmd.h>
@@ -240,9 +241,8 @@ void bitcoind_send_tx(struct lightningd_state *dstate,
 		      const struct bitcoin_tx *tx)
 {
 	u8 *raw = linearize_tx(dstate, tx);
-	char *hex = tal_arr(raw, char, hex_str_size(tal_count(raw)));
+	char *hex = tal_hexstr(raw, raw, tal_count(raw));
 
-	hex_encode(raw, tal_count(raw), hex, tal_count(hex));
 	start_bitcoin_cli(dstate, process_sendrawrx, NULL, NULL,
 			  "sendrawtransaction", hex, NULL);
 	tal_free(raw);

daemon/packets.c

@@ -11,6 +11,7 @@
 #include "protobuf_convert.h"
 #include "secrets.h"
 #include "state.h"
+#include "utils.h"
 #include <ccan/crypto/sha256/sha256.h>
 #include <ccan/io/io.h>
 #include <ccan/mem/mem.h>
@@ -22,23 +23,16 @@
 
 #define FIXME_STUB(peer) do { log_broken((peer)->dstate->base_log, "%s:%u: Implement %s!", __FILE__, __LINE__, __func__); abort(); } while(0)
 
-static char *hex_of(const tal_t *ctx, const void *p, size_t n)
-{
-	char *hex = tal_arr(ctx, char, hex_str_size(n));
-	hex_encode(p, n, hex, hex_str_size(n));
-	return hex;
-}
-
 static void dump_tx(const char *str, const struct bitcoin_tx *tx)
 {
 	u8 *linear = linearize_tx(NULL, tx);
-	printf("%s:%s\n", str, hex_of(linear, linear, tal_count(linear)));
+	printf("%s:%s\n", str, tal_hexstr(linear, linear, tal_count(linear)));
 	tal_free(linear);
 }
 
 static void dump_key(const char *str, const struct pubkey *key)
 {
-	printf("%s:%s\n", str, hex_of(NULL, key->der, sizeof(key->der)));
+	printf("%s:%s\n", str, tal_hexstr(NULL, key->der, sizeof(key->der)));
 }
 
 /* Wrap (and own!) member inside Pkt */

utils.c

@@ -0,0 +1,9 @@
+#include "utils.h"
+#include <ccan/str/hex/hex.h>
+
+char *tal_hexstr(const tal_t *ctx, const void *data, size_t len)
+{
+	char *str = tal_arr(ctx, char, hex_str_size(len));
+	hex_encode(data, len, str, hex_str_size(len));
+	return str;
+}

utils.h

@@ -0,0 +1,9 @@
+#ifndef LIGHTNING_UTILS_H
+#define LIGHTNING_UTILS_H
+#include "config.h"
+#include <ccan/tal/tal.h>
+
+/* Allocate and fill in a hex-encoded string of this data. */
+char *tal_hexstr(const tal_t *ctx, const void *data, size_t len);
+
+#endif /* LIGHTNING_UTILS_H */