Add a new rcur read-only cursor type, adapt code to use it.

Makefile

@@ -2,10 +2,10 @@ CFLAGS = -Wall -Wno-misleading-indentation -Wno-unused-function -Werror -O2 -g -
 BOLT11_HDRS := src/bolt11/amount.h src/bolt11/bech32.h src/bolt11/bech32_util.h src/bolt11/bolt11.h src/bolt11/debug.h src/bolt11/error.h src/bolt11/hash_u5.h src/bolt11/node_id.h src/bolt11/overflows.h
 CCAN_SRCS := ccan/ccan/utf8/utf8.c ccan/ccan/tal/tal.c ccan/ccan/tal/str/str.c ccan/ccan/list/list.c ccan/ccan/mem/mem.c ccan/ccan/crypto/sha256/sha256.c ccan/ccan/take/take.c
 CCAN_HDRS := ccan/ccan/utf8/utf8.h ccan/ccan/container_of/container_of.h ccan/ccan/check_type/check_type.h ccan/ccan/str/str.h ccan/ccan/tal/str/str.h ccan/ccan/tal/tal.h ccan/ccan/list/list.h ccan/ccan/structeq/structeq.h ccan/ccan/typesafe_cb/typesafe_cb.h ccan/ccan/short_types/short_types.h ccan/ccan/mem/mem.h ccan/ccan/likely/likely.h ccan/ccan/alignof/alignof.h ccan/ccan/crypto/sha256/sha256.h ccan/ccan/array_size/array_size.h ccan/ccan/endian/endian.h ccan/ccan/take/take.h ccan/ccan/build_assert/build_assert.h ccan/ccan/cppmagic/cppmagic.h
-HEADERS = deps/lmdb/lmdb.h deps/secp256k1/include/secp256k1.h src/nostrdb.h src/cursor.h src/hex.h src/jsmn.h src/config.h src/random.h src/memchr.h src/cpu.h src/nostr_bech32.h src/block.h src/str_block.h $(C_BINDINGS) $(CCAN_HDRS) $(BOLT11_HDRS)
+HEADERS = deps/lmdb/lmdb.h deps/secp256k1/include/secp256k1.h src/nostrdb.h src/cursor.h src/hex.h src/jsmn.h src/config.h src/random.h src/memchr.h src/cpu.h src/nostr_bech32.h src/block.h src/str_block.h src/rcur.h $(C_BINDINGS) $(CCAN_HDRS) $(BOLT11_HDRS)
 FLATCC_SRCS=deps/flatcc/src/runtime/json_parser.c deps/flatcc/src/runtime/verifier.c deps/flatcc/src/runtime/builder.c deps/flatcc/src/runtime/emitter.c deps/flatcc/src/runtime/refmap.c
 BOLT11_SRCS = src/bolt11/bolt11.c src/bolt11/bech32.c src/bolt11/amount.c src/bolt11/hash_u5.c
-SRCS = src/nostrdb.c src/invoice.c src/nostr_bech32.c src/content_parser.c src/block.c $(BOLT11_SRCS) $(FLATCC_SRCS) $(CCAN_SRCS)
+SRCS = src/nostrdb.c src/invoice.c src/nostr_bech32.c src/content_parser.c src/block.c src/rcur.c $(BOLT11_SRCS) $(FLATCC_SRCS) $(CCAN_SRCS)
 LDS = $(OBJS) $(ARS) 
 OBJS = $(SRCS:.c=.o)
 DEPS = $(OBJS) $(HEADERS) $(ARS)

src/block.c

@@ -2,122 +2,99 @@
 
 #include "nostrdb.h"
 #include "block.h"
+#include "rcur.h"
 #include <stdlib.h>
 
 int push_str_block(struct cursor *buf, const char *content, struct ndb_str_block *block) {
 	return cursor_push_varint(buf, block->str - content) &&
 	       cursor_push_varint(buf, block->len);
 }
 
-int pull_str_block(struct cursor *buf, const char *content, struct ndb_str_block *block) {
-	uint32_t start;
-	if (!cursor_pull_varint_u32(buf, &start))
-		return 0;
+bool pull_str_block(struct rcur *rcur, const char *content, struct ndb_str_block *block) {
+	block->str = content + rcur_pull_varint_u32(rcur);
+	block->len = rcur_pull_varint_u32(rcur);
 
-	block->str = content + start;
-
-	return cursor_pull_varint_u32(buf, &block->len);
+	return rcur_valid(rcur);
 }
 
-static int pull_nostr_bech32_type(struct cursor *cur, enum nostr_bech32_type *type)
+static bool pull_nostr_bech32_type(struct rcur *rcur, enum nostr_bech32_type *type)
 {
 	uint64_t inttype;
-	if (!cursor_pull_varint(cur, &inttype))
-		return 0;
 
-	if (inttype <= 0 || inttype > NOSTR_BECH32_KNOWN_TYPES)
-		return 0;
+	// Returns 0 on failure.
+	inttype = rcur_pull_varint(rcur);
+	if (inttype <= 0 || inttype > NOSTR_BECH32_KNOWN_TYPES) {
+		rcur_fail(rcur);
+		return false;
+	}
 
 	*type = inttype;
-	return 1;
+	return true;
 }
 
 
-static int pull_bech32_mention(const char *content, struct cursor *cur, struct ndb_mention_bech32_block *block) {
+static bool pull_bech32_mention(const char *content, struct rcur *rcur, struct ndb_mention_bech32_block *block) {
 	uint16_t size;
-	unsigned char *start;
-	struct cursor bech32;
-
-	if (!pull_str_block(cur, content, &block->str))
-		return 0;
-
-	if (!cursor_pull_u16(cur, &size))
-		return 0;
-
-	if (!pull_nostr_bech32_type(cur, &block->bech32.type))
-		return 0;
-
-	make_cursor(cur->p, cur->p + size, &bech32);
+	struct rcur bech32;
 
-	start = cur->p;
+	pull_str_block(rcur, content, &block->str);
+	size = rcur_pull_u16(rcur);
+	pull_nostr_bech32_type(rcur, &block->bech32.type);
 
-	if (!parse_nostr_bech32_buffer(&bech32, block->bech32.type, &block->bech32))
-		return 0;
+	bech32 = rcur_pull_slice(rcur, size);
+	parse_nostr_bech32_buffer(&bech32, block->bech32.type, &block->bech32);
+	if (!rcur_valid(&bech32))
+		rcur_fail(rcur);
 
-	//assert(bech32.p == start + size);
-	cur->p = start + size;
-	return 1;
+	return rcur_valid(rcur);
 }
 
-static int pull_invoice(const char *content, struct cursor *cur,
-			struct ndb_invoice_block *block)
+static bool pull_invoice(const char *content, struct rcur *rcur,
+			 struct ndb_invoice_block *block)
 {
-	if (!pull_str_block(cur, content, &block->invstr))
-		return 0;
-
-	return ndb_decode_invoice(cur, &block->invoice);
+	pull_str_block(rcur, content, &block->invstr);
+	return ndb_decode_invoice(rcur, &block->invoice);
 }
 
-static int pull_block_type(struct cursor *cur, enum ndb_block_type *type)
+static bool pull_block_type(struct rcur *rcur, enum ndb_block_type *type)
 {
 	uint32_t itype;
-	*type = 0;
-	if (!cursor_pull_varint_u32(cur, &itype))
-		return 0;
 
-	if (itype <= 0 || itype > NDB_NUM_BLOCK_TYPES)
-		return 0;
+	itype = rcur_pull_varint_u32(rcur);
+	if (itype <= 0 || itype > NDB_NUM_BLOCK_TYPES) {
+		rcur_fail(rcur);
+		return false;
+	}
 
 	*type = itype;
-	return 1;
+	return true;
 }
 
-static int pull_block(const char *content, struct cursor *cur, struct ndb_block *block)
+static bool pull_block(const char *content, struct rcur *rcur, struct ndb_block *block)
 {
-	unsigned char *start = cur->p;
-
-	if (!pull_block_type(cur, &block->type))
-		return 0;
+	if (!pull_block_type(rcur, &block->type))
+		return false;
 
 	switch (block->type) {
 	case BLOCK_HASHTAG:
 	case BLOCK_TEXT:
 	case BLOCK_URL:
-		if (!pull_str_block(cur, content, &block->block.str))
-			goto fail;
-		break;
+		return pull_str_block(rcur, content, &block->block.str);
 
 	case BLOCK_MENTION_INDEX:
-		if (!cursor_pull_varint_u32(cur, &block->block.mention_index))
-			goto fail;
-		break;
+		block->block.mention_index = rcur_pull_varint_u32(rcur);
+		return rcur_valid(rcur);
 
 	case BLOCK_MENTION_BECH32:
-		if (!pull_bech32_mention(content, cur, &block->block.mention_bech32))
-			goto fail;
-		break;
+		return pull_bech32_mention(content, rcur, &block->block.mention_bech32);
 
 	case BLOCK_INVOICE:
 		// we only push invoice strs here
-		if (!pull_invoice(content, cur, &block->block.invoice))
-			goto fail;
-		break;
+		return pull_invoice(content, rcur, &block->block.invoice);
 	}
 
-	return 1;
-fail:
-	cur->p = start;
-	return 0;
+	/* unreachable: pull_block_type can only return known types */
+	assert(0);
 }
 
 
@@ -129,27 +106,15 @@ enum ndb_block_type ndb_get_block_type(struct ndb_block *block) {
 void ndb_blocks_iterate_start(const char *content, struct ndb_blocks *blocks, struct ndb_block_iterator *iter) {
 	iter->blocks = blocks;
 	iter->content = content;
-	iter->p = blocks->blocks;
+	iter->rcur = rcur_forbuf(blocks->blocks, iter->blocks->blocks_size);
 }
 
 struct ndb_block *ndb_blocks_iterate_next(struct ndb_block_iterator *iter)
 {
-	struct cursor cur;
-	cur.start = iter->blocks->blocks;
-	cur.p = iter->p;
-	cur.end = iter->blocks->blocks + iter->blocks->blocks_size;
-
-	while (cur.p < cur.end) {
-		if (!pull_block(iter->content, &cur, &iter->block)) {
-			iter->p = cur.p;
-			return NULL;
-		} else {
-			iter->p = cur.p;
-			return &iter->block;
-		}
-	}
+	if (!pull_block(iter->content, &iter->rcur, &iter->block))
+		return NULL;
 
-	return NULL;
+	return &iter->block;
 }
 
 // STR BLOCKS

src/block.h

@@ -8,6 +8,7 @@
 #include "nostr_bech32.h"
 #include "nostrdb.h"
 #include <inttypes.h>
+#include <stdbool.h>
 
 #define NDB_BLOCK_FLAG_OWNED 1
 
@@ -29,8 +30,9 @@ struct ndb_blocks {
 
 #pragma pack(pop)
 
-int push_str_block(struct cursor *buf, const char *content, struct ndb_str_block *block);
-int pull_str_block(struct cursor *buf, const char *content, struct ndb_str_block *block);
+struct rcur;
 
+int push_str_block(struct cursor *buf, const char *content, struct ndb_str_block *block);
+bool pull_str_block(struct rcur *rcur, const char *content, struct ndb_str_block *block);
 
 #endif // NDB_BLOCK_H