db: Make the `db` struct private and provide accessors instead

We will soon generalize the DB, so directly reaching into the `struct db`
instance to talk to the sqlite3 connection is bad anyway. This increases
flexibility and allows us to tailor the actual implementation to the
underlying DB.

Signed-off-by: Christian Decker <decker.christian@gmail.com>

lightningd/subd.c

@@ -555,7 +555,7 @@ static void destroy_subd(struct subd *sd)
 		sd->channel = NULL;
 
 		/* We can be freed both inside msg handling, or spontaneously. */
-		outer_transaction = db->in_transaction;
+		outer_transaction = db_in_transaction(db);
 		if (!outer_transaction)
 			db_begin_transaction(db);
 		if (sd->errcb)

lightningd/test/run-find_my_abspath.c

@@ -57,6 +57,9 @@ void db_commit_transaction(struct db *db UNNEEDED)
 /* Generated stub for db_get_intvar */
 s64 db_get_intvar(struct db *db UNNEEDED, char *varname UNNEEDED, s64 defval UNNEEDED)
 { fprintf(stderr, "db_get_intvar called!\n"); abort(); }
+/* Generated stub for db_in_transaction */
+bool db_in_transaction(struct db *db UNNEEDED)
+{ fprintf(stderr, "db_in_transaction called!\n"); abort(); }
 /* Generated stub for fatal */
 void   fatal(const char *fmt UNNEEDED, ...)
 { fprintf(stderr, "fatal called!\n"); abort(); }

wallet/db.c

@@ -23,6 +23,13 @@ struct migration {
 	void (*func)(struct lightningd *ld, struct db *db);
 };
 
+struct db {
+	char *filename;
+	const char *in_transaction;
+	sqlite3 *sql;
+	const char **changes;
+};
+
 void migrate_pr2342_feerate_per_channel(struct lightningd *ld, struct db *db);
 
 /* Do not reorder or remove elements from this array, it is used to
@@ -685,6 +692,21 @@ static void db_prepare_for_changes(struct db *db)
 	db->changes = tal_arr(db, const char *, 0);
 }
 
+bool db_in_transaction(struct db *db)
+{
+	return db->in_transaction;
+}
+
+u64 db_last_insert_id(struct db *db)
+{
+	return sqlite3_last_insert_rowid(db->sql);
+}
+
+size_t db_changes(struct db *db)
+{
+	return sqlite3_changes(db->sql);
+}
+
 void db_begin_transaction_(struct db *db, const char *location)
 {
 	if (db->in_transaction)

wallet/db.h

@@ -18,12 +18,7 @@ struct lightningd;
 struct log;
 struct node_id;
 
-struct db {
-	char *filename;
-	const char *in_transaction;
-	sqlite3 *sql;
-	const char **changes;
-};
+struct db;
 
 /**
  * Macro to annotate a named SQL query.
@@ -79,6 +74,16 @@ sqlite3_stmt *db_select_(const char *location, struct db *db, const char *query)
 	db_begin_transaction_((db), __FILE__ ":" stringify(__LINE__))
 void db_begin_transaction_(struct db *db, const char *location);
 
+bool db_in_transaction(struct db *db);
+
+// FIXME(cdecker) Need to maybe add a pointer to the db_stmt we are referring to
+// FIXME(cdecker) Comment
+u64 db_last_insert_id(struct db *db);
+
+// FIXME(cdecker) Need to maybe add a pointer to the db_stmt we are referring to
+// FIXME(cdecker) Comment
+size_t db_changes(struct db *db);
+
 /**
  * db_commit_transaction - Commit a running transaction
  *

wallet/invoices.c

@@ -305,7 +305,7 @@ bool invoices_create(struct invoices *invoices,
 
 	db_exec_prepared(invoices->db, stmt);
 
-	pinvoice->id = sqlite3_last_insert_rowid(invoices->db->sql);
+	pinvoice->id = db_last_insert_id(invoices->db);
 
 	/* Install expiration trigger. */
 	if (!invoices->expiration_timer ||
@@ -392,7 +392,7 @@ bool invoices_delete(struct invoices *invoices,
 	sqlite3_bind_int64(stmt, 1, invoice.id);
 	db_exec_prepared(invoices->db, stmt);
 
-	if (sqlite3_changes(invoices->db->sql) != 1)
+	if (db_changes(invoices->db) != 1)
 		return false;
 
 	/* Tell all the waiters about the fact that it was deleted. */

wallet/wallet.c

@@ -200,7 +200,7 @@ bool wallet_update_output_status(struct wallet *w,
 		sqlite3_bind_int(stmt, 3, outnum);
 	}
 	db_exec_prepared(w->db, stmt);
-	return sqlite3_changes(w->db->sql) > 0;
+	return db_changes(w->db) > 0;
 }
 
 struct utxo **wallet_get_utxos(const tal_t *ctx, struct wallet *w, const enum output_status state)
@@ -546,7 +546,7 @@ static void wallet_shachain_init(struct wallet *wallet,
 	sqlite3_bind_int64(stmt, 1, chain->chain.min_index);
 	db_exec_prepared(wallet->db, stmt);
 
-	chain->id = sqlite3_last_insert_rowid(wallet->db->sql);
+	chain->id = db_last_insert_id(wallet->db);
 }
 
 /* TODO(cdecker) Stolen from shachain, move to some appropriate location */
@@ -1067,7 +1067,7 @@ static void wallet_channel_config_insert(struct wallet *w,
 
 	stmt = db_prepare(w->db, "INSERT INTO channel_configs DEFAULT VALUES;");
 	db_exec_prepared(w->db, stmt);
-	cc->id = sqlite3_last_insert_rowid(w->db->sql);
+	cc->id = db_last_insert_id(w->db);
 }
 
 static void wallet_channel_config_save(struct wallet *w,
@@ -1293,7 +1293,7 @@ void wallet_channel_insert(struct wallet *w, struct channel *chan)
 				  type_to_string(tmpctx, struct wireaddr_internal, &chan->peer->addr),
 				  -1, SQLITE_TRANSIENT);
 		db_exec_prepared(w->db, stmt);
-		chan->peer->dbid = sqlite3_last_insert_rowid(w->db->sql);
+		chan->peer->dbid = db_last_insert_id(w->db);
 	}
 
 	/* Insert a stub, that we update, unifies INSERT and UPDATE paths */
@@ -1512,7 +1512,7 @@ void wallet_htlc_save_in(struct wallet *wallet,
 	sqlite3_bind_timeabs(stmt, 11, in->received_time);
 
 	db_exec_prepared(wallet->db, stmt);
-	in->dbid = sqlite3_last_insert_rowid(wallet->db->sql);
+	in->dbid = db_last_insert_id(wallet->db);
 }
 
 void wallet_htlc_save_out(struct wallet *wallet,
@@ -1562,7 +1562,7 @@ void wallet_htlc_save_out(struct wallet *wallet,
 
 	db_exec_prepared(wallet->db, stmt);
 
-	out->dbid = sqlite3_last_insert_rowid(wallet->db->sql);
+	out->dbid = db_last_insert_id(wallet->db);
 }
 
 void wallet_htlc_update(struct wallet *wallet, const u64 htlc_dbid,
@@ -2518,7 +2518,7 @@ wallet_outpoint_spend(struct wallet *w, const tal_t *ctx, const u32 blockheight,
 
 		db_exec_prepared(w->db, stmt);
 
-		if (sqlite3_changes(w->db->sql) == 0) {
+		if (db_changes(w->db) == 0) {
 			return NULL;
 		}