sendpays: add to wait subsystem.

Adding an index means:

1. Add the new subsystem, and new updated_index field to the db, and
   create xxx_index_deleted/created/updated APIs.
2. Hook up these functions to the points they need to be called.
3. Add index, start and limit fields to the list command.
4. Add created_index and updated_index into the list command.

This does #1.

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

lightningd/pay.c

@@ -1690,6 +1690,52 @@ static const struct json_command waitsendpay_command = {
 };
 AUTODATA(json_command, &waitsendpay_command);
 
+static u64 sendpay_index_inc(struct lightningd *ld,
+			     const struct sha256 *payment_hash,
+			     u64 partid,
+			     u64 groupid,
+			     enum payment_status status,
+			     enum wait_index idx)
+{
+	return wait_index_increment(ld, WAIT_SUBSYSTEM_SENDPAY, idx,
+				    "status", payment_status_to_string(status),
+				    "=partid", tal_fmt(tmpctx, "%"PRIu64, partid),
+				    "=groupid", tal_fmt(tmpctx, "%"PRIu64, groupid),
+				    "payment_hash",
+				    type_to_string(tmpctx, struct sha256, payment_hash),
+				    NULL);
+}
+
+void sendpay_index_deleted(struct lightningd *ld,
+			   const struct sha256 *payment_hash,
+			   u64 partid,
+			   u64 groupid,
+			   enum payment_status status)
+{
+	sendpay_index_inc(ld, payment_hash, partid, groupid, status, WAIT_INDEX_DELETED);
+}
+
+/* Fortuntely, dbids start at 1, not 0! */
+u64 sendpay_index_created(struct lightningd *ld,
+			  const struct sha256 *payment_hash,
+			  u64 partid,
+			  u64 groupid,
+			  enum payment_status status)
+{
+	return sendpay_index_inc(ld, payment_hash, partid, groupid, status,
+				 WAIT_INDEX_CREATED);
+}
+
+u64 sendpay_index_update_status(struct lightningd *ld,
+				const struct sha256 *payment_hash,
+				u64 partid,
+				u64 groupid,
+				enum payment_status status)
+{
+	return sendpay_index_inc(ld, payment_hash, partid, groupid, status,
+				 WAIT_INDEX_UPDATED);
+}
+
 static struct command_result *param_payment_status(struct command *cmd,
 						   const char *name,
 						   const char *buffer,

lightningd/pay.h

@@ -2,6 +2,7 @@
 #define LIGHTNING_LIGHTNINGD_PAY_H
 #include "config.h"
 #include <common/errcode.h>
+#include <wallet/wallet.h>
 
 struct htlc_out;
 struct lightningd;
@@ -35,4 +36,20 @@ void json_sendpay_fail_fields(struct json_stream *js,
 			      const struct onionreply *onionreply,
 			      const struct routing_failure *fail);
 
+/* wait() hooks in here */
+void sendpay_index_deleted(struct lightningd *ld,
+			   const struct sha256 *payment_hash,
+			   u64 partid,
+			   u64 groupid,
+			   enum payment_status status);
+u64 sendpay_index_created(struct lightningd *ld,
+			  const struct sha256 *payment_hash,
+			  u64 partid,
+			  u64 groupid,
+			  enum payment_status status);
+u64 sendpay_index_update_status(struct lightningd *ld,
+				const struct sha256 *payment_hash,
+				u64 partid,
+				u64 groupid,
+				enum payment_status status);
 #endif /* LIGHTNING_LIGHTNINGD_PAY_H */

lightningd/wait.c

@@ -20,6 +20,7 @@ struct waiter {
 
 
 static const char *subsystem_names[] = {
+	"sendpays",
 	"invoices",
 };
 
@@ -44,6 +45,8 @@ const char *wait_index_name(enum wait_index index)
 const char *wait_subsystem_name(enum wait_subsystem subsystem)
 {
 	switch (subsystem) {
+	case WAIT_SUBSYSTEM_SENDPAY:
+		return subsystem_names[subsystem];
 	case WAIT_SUBSYSTEM_INVOICE:
 		return subsystem_names[subsystem];
 	}

lightningd/wait.h

@@ -7,7 +7,8 @@ struct lightningd;
 
 /* This WAIT_SUBSYSTEM_X corresponds to listX */
 enum wait_subsystem {
-	WAIT_SUBSYSTEM_INVOICE
+	WAIT_SUBSYSTEM_SENDPAY,
+	WAIT_SUBSYSTEM_INVOICE,
 };
 #define NUM_WAIT_SUBSYSTEM (WAIT_SUBSYSTEM_INVOICE+1)
 

wallet/db.c

@@ -994,6 +994,8 @@ static struct migration dbmigrations[] = {
 	 "  commitment_fee BIGINT,"
 	 "  commitment_weight INTEGER)"), NULL},
     {SQL("CREATE INDEX local_anchors_idx ON local_anchors (channel_id)"), NULL},
+    {SQL("ALTER TABLE payments ADD updated_index BIGINT DEFAULT 0"), NULL},
+    {SQL("CREATE INDEX payments_update_idx ON payments (updated_index)"), NULL},
 };
 
 /**