wallet: Return both min and max block heights

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

lightningd/lightningd.c

@@ -306,7 +306,7 @@ void notify_new_block(struct lightningd *ld,
 int main(int argc, char *argv[])
 {
 	struct lightningd *ld;
-	u32 blockheight;
+	u32 blockheight, first_block;
 
 	setup_locale();
 	daemon_setup(argv[0], log_backtrace_print, log_backtrace_exit);
@@ -388,7 +388,7 @@ int main(int argc, char *argv[])
 	/* Get the blockheight we are currently at, UINT32_MAX is used to signal
 	 * an unitialized wallet and that we should start off of bitcoind's
 	 * current height */
-	blockheight = wallet_blocks_height(ld->wallet, UINT32_MAX);
+	wallet_blocks_heights(ld->wallet, UINT32_MAX, &first_block, &blockheight);
 
 	/* If we were asked to rescan from an absolute height (--rescan < 0)
 	 * then just go there. Otherwise take compute the diff to our current

lightningd/test/run-find_my_path.c

@@ -121,9 +121,9 @@ struct txfilter *txfilter_new(const tal_t *ctx UNNEEDED)
 /* Generated stub for version */
 const char *version(void)
 { fprintf(stderr, "version called!\n"); abort(); }
-/* Generated stub for wallet_blocks_height */
-u32 wallet_blocks_height(struct wallet *w UNNEEDED, u32 def UNNEEDED)
-{ fprintf(stderr, "wallet_blocks_height called!\n"); abort(); }
+/* Generated stub for wallet_blocks_heights */
+void wallet_blocks_heights(struct wallet *w UNNEEDED, u32 def UNNEEDED, u32 *min UNNEEDED, u32 *max UNNEEDED)
+{ fprintf(stderr, "wallet_blocks_heights called!\n"); abort(); }
 /* Generated stub for wallet_channels_load_active */
 bool wallet_channels_load_active(const tal_t *ctx UNNEEDED, struct wallet *w UNNEEDED)
 { fprintf(stderr, "wallet_channels_load_active called!\n"); abort(); }

wallet/wallet.c

@@ -769,20 +769,20 @@ void wallet_channel_stats_load(struct wallet *w,
 	db_stmt_done(stmt);
 }
 
-u32 wallet_blocks_height(struct wallet *w, u32 def)
+void wallet_blocks_heights(struct wallet *w, u32 def, u32 *min, u32 *max)
 {
-	u32 blockheight;
-	sqlite3_stmt *stmt = db_prepare(w->db, "SELECT MAX(height) FROM blocks;");
+	assert(min != NULL && max != NULL);
+	sqlite3_stmt *stmt = db_prepare(w->db, "SELECT MIN(height), MAX(height) FROM blocks;");
 
 	/* If we ever processed a block we'll get the latest block in the chain */
 	if (sqlite3_step(stmt) == SQLITE_ROW && sqlite3_column_type(stmt, 0) != SQLITE_NULL) {
-		blockheight = sqlite3_column_int(stmt, 0);
-		db_stmt_done(stmt);
-		return blockheight;
+		*min = sqlite3_column_int(stmt, 0);
+		*max = sqlite3_column_int(stmt, 1);
 	} else {
-		db_stmt_done(stmt);
-		return def;
+		*min = def;
+		*max = def;
 	}
+	db_stmt_done(stmt);
 }
 
 static void wallet_channel_config_insert(struct wallet *w,

wallet/wallet.h

@@ -316,13 +316,15 @@ void wallet_channel_stats_load(struct wallet *w, u64 cdbid, struct channel_stats
 /**
  * Retrieve the blockheight of the last block processed by lightningd.
  *
- * Will return either the maximal blockheight or the default value if the wallet
- * was never used before.
+ * Will set min/max either the minimal/maximal blockheight or the default value
+ * if the wallet was never used before.
  *
  * @w: wallet to load from.
  * @def: the default value to return if we've never used the wallet before
+ * @min(out): height of the first block we track
+ * @max(out): height of the last block we added
  */
-u32 wallet_blocks_height(struct wallet *w, u32 def);
+void wallet_blocks_heights(struct wallet *w, u32 def, u32 *min, u32 *max);
 
 /**
  * wallet_extract_owned_outputs - given a tx, extract all of our outputs