invoice: order by when they were paid.

We need some ordering to deliver them to the JSON "waitinvoice" command;
we use a counter where 0 means "unpaid".

We keep two lists now, one for unpaid and one for paid invoices.

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

daemon/db.c

@@ -1088,23 +1088,22 @@ static void db_load_invoice(struct lightningd_state *dstate)
 
 	while ((err = sqlite3_step(stmt)) != SQLITE_DONE) {
 		struct rval r;
-		u64 msatoshi;
-		bool complete;
+		u64 msatoshi, paid_num;
 		const char *label;
 
 		if (err != SQLITE_ROW)
 			fatal("db_load_invoice:step gave %s:%s",
 			      sqlite3_errstr(err),
 			      sqlite3_errmsg(dstate->db->sql));
-		if (sqlite3_column_count(stmt) != 3)
-			fatal("db_load_pay:step gave %i cols, not 3",
+		if (sqlite3_column_count(stmt) != 4)
+			fatal("db_load_invoice:step gave %i cols, not 4",
 			      sqlite3_column_count(stmt));
 
 		from_sql_blob(stmt, 0, &r, sizeof(r));
 		msatoshi = sqlite3_column_int64(stmt, 1);
 		label = (const char *)sqlite3_column_text(stmt, 2);
-		complete = sqlite3_column_int(stmt, 3);
-		invoice_add(dstate, &r, msatoshi, label, complete);
+		paid_num = sqlite3_column_int64(stmt, 3);
+		invoice_add(dstate, &r, msatoshi, label, paid_num);
 	}
 	tal_free(ctx);
 }
@@ -1199,8 +1198,8 @@ void db_init(struct lightningd_state *dstate)
 			       "PRIMARY KEY(rhash)")
 			 TABLE(invoice,
 			       SQL_R(r), SQL_U64(msatoshi), SQL_INVLABEL(label),
-			       SQL_BOOL(complete),
-			       "PRIMARY KEY(r)")
+			       SQL_U64(paid_num),
+			       "PRIMARY KEY(label)")
 			 TABLE(anchors,
 			       SQL_PUBKEY(peer),
 			       SQL_TXID(txid), SQL_U32(idx), SQL_U64(amount),
@@ -1953,7 +1952,8 @@ bool db_new_invoice(struct lightningd_state *dstate,
 	return !errmsg;
 }
 
-bool db_resolve_invoice(struct lightningd_state *dstate, const struct rval *r)
+bool db_resolve_invoice(struct lightningd_state *dstate,
+			const char *label, u64 paid_num)
 {
 	const char *errmsg, *ctx = tal(dstate, char);
 
@@ -1961,9 +1961,8 @@ bool db_resolve_invoice(struct lightningd_state *dstate, const struct rval *r)
 
 	assert(dstate->db->in_transaction);
 	
-	errmsg = db_exec(ctx, dstate, "UPDATE invoice SET complete=%s WHERE r=x'%s';",
-			 sql_bool(true),
-			 tal_hexstr(ctx, r, sizeof(*r)));
+	errmsg = db_exec(ctx, dstate, "UPDATE invoice SET paid_num=%"PRIu64" WHERE label=x'%s';",
+			 paid_num, tal_hexstr(ctx, label, strlen(label)));
 	if (errmsg)
 		log_broken(dstate->base_log, "%s:%s", __func__, errmsg);
 	tal_free(ctx);

daemon/db.h

@@ -55,7 +55,8 @@ bool db_update_htlc_state(struct peer *peer, const struct htlc *htlc,
 				 enum htlc_state oldstate);
 bool db_complete_pay_command(struct lightningd_state *dstate,
 			     const struct htlc *htlc);
-bool db_resolve_invoice(struct lightningd_state *dstate, const struct rval *r);
+bool db_resolve_invoice(struct lightningd_state *dstate,
+			const char *label, u64 paid_num);
 bool db_update_feechange_state(struct peer *peer,
 			       const struct feechange *f,
 			       enum htlc_state oldstate);

daemon/invoice.c

@@ -7,24 +7,36 @@
 #include <ccan/tal/str/str.h>
 #include <sodium/randombytes.h>
 
-struct invoice *find_invoice(struct lightningd_state *dstate,
+static struct invoice *find_inv(const struct list_head *list,
 				const struct sha256 *rhash)
 {
 	struct invoice *i;
 
-	list_for_each(&dstate->invoices, i, list) {
+	list_for_each(list, i, list) {
 		if (structeq(rhash, &i->rhash))
 			return i;
 	}
 	return NULL;
 }
 
-static struct invoice *find_invoice_by_label(struct lightningd_state *dstate,
+struct invoice *find_unpaid(struct lightningd_state *dstate,
+			     const struct sha256 *rhash)
+{
+	return find_inv(&dstate->unpaid, rhash);
+}
+
+static struct invoice *find_paid(struct lightningd_state *dstate,
+				 const struct sha256 *rhash)
+{
+	return find_inv(&dstate->paid, rhash);
+}
+
+static struct invoice *find_invoice_by_label(const struct list_head *list,
 					     const char *label)
 {
 	struct invoice *i;
 
-	list_for_each(&dstate->invoices, i, list) {
+	list_for_each(list, i, list) {
 		if (streq(i->label, label))
 			return i;
 	}
@@ -35,16 +47,31 @@ void invoice_add(struct lightningd_state *dstate,
 		 const struct rval *r,
 		 u64 msatoshi,
 		 const char *label,
-		 bool complete)
+		 u64 paid_num)
 {
 	struct invoice *invoice = tal(dstate, struct invoice);
 
 	invoice->msatoshi = msatoshi;
 	invoice->r = *r;
-	invoice->complete = complete;
+	invoice->paid_num = paid_num;
 	invoice->label = tal_strdup(invoice, label);
 	sha256(&invoice->rhash, invoice->r.r, sizeof(invoice->r.r));
-	list_add(&dstate->invoices, &invoice->list);
+
+	if (paid_num) {
+		list_add(&dstate->paid, &invoice->list);
+		if (paid_num > dstate->invoices_completed)
+			dstate->invoices_completed = paid_num;
+	} else
+		list_add(&dstate->unpaid, &invoice->list);
+}
+
+bool resolve_invoice(struct lightningd_state *dstate,
+		     struct invoice *invoice)
+{
+	invoice->paid_num = ++dstate->invoices_completed;
+	list_del_from(&dstate->unpaid, &invoice->list);
+	list_add_tail(&dstate->paid, &invoice->list);
+	return db_resolve_invoice(dstate, invoice->label, invoice->paid_num);
 }
 	
 static void json_invoice(struct command *cmd,
@@ -75,7 +102,8 @@ static void json_invoice(struct command *cmd,
 		randombytes_buf(invoice->r.r, sizeof(invoice->r.r));
 
 	sha256(&invoice->rhash, invoice->r.r, sizeof(invoice->r.r));
-	if (find_invoice(cmd->dstate, &invoice->rhash)) {
+	if (find_unpaid(cmd->dstate, &invoice->rhash)
+	    || find_paid(cmd->dstate, &invoice->rhash)) {
 		command_fail(cmd, "Duplicate r value '%.*s'",
 			     r->end - r->start, buffer + r->start);
 		return;
@@ -91,7 +119,8 @@ static void json_invoice(struct command *cmd,
 
 	invoice->label = tal_strndup(invoice, buffer + label->start,
 				     label->end - label->start);
-	if (find_invoice_by_label(cmd->dstate, invoice->label)) {
+	if (find_invoice_by_label(&cmd->dstate->paid, invoice->label)
+	    || find_invoice_by_label(&cmd->dstate->unpaid, invoice->label)) {
 		command_fail(cmd, "Duplicate label '%s'", invoice->label);
 		return;
 	}
@@ -100,7 +129,7 @@ static void json_invoice(struct command *cmd,
 			     INVOICE_MAX_LABEL_LEN);
 		return;
 	}
-	invoice->complete = false;
+	invoice->paid_num = 0;
 
 	if (!db_new_invoice(cmd->dstate, invoice->msatoshi, invoice->label,
 			    &invoice->r)) {
@@ -109,7 +138,7 @@ static void json_invoice(struct command *cmd,
 	}		
 	/* OK, connect it to main state, respond with hash */
 	tal_steal(cmd->dstate, invoice);
-	list_add(&cmd->dstate->invoices, &invoice->list);
+	list_add(&cmd->dstate->unpaid, &invoice->list);
 
 	json_object_start(response, NULL);
 	json_add_hex(response, "rhash",
@@ -126,10 +155,27 @@ const struct json_command invoice_command = {
 	"Returns the {rhash} on success. "
 };
 
+static void json_add_invoices(struct json_result *response,
+			      const struct list_head *list,
+			      const char *buffer, const jsmntok_t *label)
+{
+	struct invoice *i;
+
+	list_for_each(list, i, list) {
+		if (label && !json_tok_streq(buffer, label, i->label))
+			continue;
+		json_object_start(response, NULL);
+		json_add_string(response, "label", i->label);
+		json_add_hex(response, "rhash", &i->rhash, sizeof(i->rhash));
+		json_add_u64(response, "msatoshi", i->msatoshi);
+		json_add_bool(response, "complete", i->paid_num != 0);
+		json_object_end(response);
+	}
+}
+
 static void json_listinvoice(struct command *cmd,
 			     const char *buffer, const jsmntok_t *params)
 {
-	struct invoice *i;
 	jsmntok_t *label = NULL;
 	struct json_result *response = new_json_result(cmd);	
 
@@ -143,16 +189,8 @@ static void json_listinvoice(struct command *cmd,
 	
 	json_object_start(response, NULL);
 	json_array_start(response, NULL);
-	list_for_each(&cmd->dstate->invoices, i, list) {
-		if (label && !json_tok_streq(buffer, label, i->label))
-			continue;
-		json_object_start(response, NULL);
-		json_add_string(response, "label", i->label);
-		json_add_hex(response, "rhash", &i->rhash, sizeof(i->rhash));
-		json_add_u64(response, "msatoshi", i->msatoshi);
-		json_add_bool(response, "complete", i->complete);
-		json_object_end(response);
-	}
+	json_add_invoices(response, &cmd->dstate->paid, buffer, label);
+	json_add_invoices(response, &cmd->dstate->unpaid, buffer, label);
 	json_array_end(response);
 	json_object_end(response);
 	command_success(cmd, response);
@@ -182,20 +220,16 @@ static void json_delinvoice(struct command *cmd,
 
 	label = tal_strndup(cmd, buffer + labeltok->start,
 			    labeltok->end - labeltok->start);
-	i = find_invoice_by_label(cmd->dstate, label);
+	i = find_invoice_by_label(&cmd->dstate->unpaid, label);
 	if (!i) {
 		command_fail(cmd, "Unknown invoice");
 		return;
 	}
-	if (i->complete) {
-		command_fail(cmd, "Invoice already paid");
-		return;
-	}
 	if (!db_remove_invoice(cmd->dstate, i->label)) {
 		command_fail(cmd, "Database error");
 		return;
 	}
-	list_del_from(&cmd->dstate->invoices, &i->list);
+	list_del_from(&cmd->dstate->unpaid, &i->list);
 	
 	json_object_start(response, NULL);
 	json_add_string(response, "label", i->label);

daemon/invoice.h

@@ -11,7 +11,7 @@ struct invoice {
 	u64 msatoshi;
 	struct rval r;
 	struct sha256 rhash;
-	bool complete;
+	u64 paid_num;
 };
 
 #define INVOICE_MAX_LABEL_LEN 128
@@ -21,9 +21,12 @@ void invoice_add(struct lightningd_state *dstate,
 		 const struct rval *r,
 		 u64 msatoshi,
 		 const char *label,
-		 bool complete);
+		 u64 complete);
 
-struct invoice *find_invoice(struct lightningd_state *dstate,
+bool resolve_invoice(struct lightningd_state *dstate,
+		     struct invoice *invoice);
+
+struct invoice *find_unpaid(struct lightningd_state *dstate,
 			    const struct sha256 *rhash);
 
 #endif /* LIGHTNING_DAEMON_INVOICE_H */

daemon/lightningd.c

@@ -255,7 +255,9 @@ static struct lightningd_state *lightningd_state(void)
 	default_config(&dstate->config);
 	list_head_init(&dstate->bitcoin_req);
 	list_head_init(&dstate->wallet);
-	list_head_init(&dstate->invoices);
+	list_head_init(&dstate->unpaid);
+	list_head_init(&dstate->paid);
+	dstate->invoices_completed = 0;
 	list_head_init(&dstate->addresses);
 	dstate->dev_never_routefail = false;
 	dstate->bitcoin_req_running = false;

daemon/lightningd.h

@@ -111,7 +111,8 @@ struct lightningd_state {
 	struct list_head wallet;
 
 	/* Payments for r values we know about. */
-	struct list_head invoices;
+	struct list_head paid, unpaid;
+	u64 invoices_completed;
 
 	/* All known nodes. */
 	struct node_map *nodes;

daemon/peer.c

@@ -535,7 +535,7 @@ static void their_htlc_added(struct peer *peer, struct htlc *htlc,
 	case ROUTE_STEP__NEXT_END:
 		if (only_dest)
 			return;
-		invoice = find_invoice(peer->dstate, &htlc->rhash);
+		invoice = find_unpaid(peer->dstate, &htlc->rhash);
 		if (!invoice) {
 			log_unusual(peer->log, "No invoice for HTLC %"PRIu64,
 				    htlc->id);
@@ -561,28 +561,16 @@ static void their_htlc_added(struct peer *peer, struct htlc *htlc,
 			return;
 		}
 
-		/* This is a courtesy: we could simply take your money! */
-		if (invoice->complete) {
-			log_unusual(peer->log,
-				    "Repeated payment for '%s' HTLC %"PRIu64,
-				    invoice->label, htlc->id);
-			command_htlc_set_fail(peer, htlc,
-					      UNAUTHORIZED_401,
-					      "already received payment");
-			return;
-		}
-
 		log_info(peer->log, "Immediately resolving '%s' HTLC %"PRIu64,
 			 invoice->label, htlc->id);
 
-		if (!db_resolve_invoice(peer->dstate, &invoice->r)) {
+		if (!resolve_invoice(peer->dstate, invoice)) {
 			command_htlc_set_fail(peer, htlc,
 					      INTERNAL_SERVER_ERROR_500,
 					      "database error");
 			return;
 		}
 
-		invoice->complete = true;
 		set_htlc_rval(peer, htlc, &invoice->r);
 		command_htlc_fulfill(peer, htlc);
 		goto free_rest;