lightningd: simplify datastore internal db API.

The wallet_datastore_first() SELECT statement only iterates from the
given key (if any), relying on the caller to notice when the key no
longer applies.  (e.g. startkey = ["foo", "bar"] will return key
["foo", "bar"] then ["foo", "bar", "child" ], then ["foo", "baz"]).

The only caller (listdatastore) would notice the keychange and stop
looping, but reallly wallet_datastore_next() should do this.  When I
tried to use it for migrations, I got very confused!

Also, several places want a simple "wallet_datastore_get()" function,
so provide that.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
2023-07-25 11:21:43 +09:30
parent 16d73979a0
commit e39c80bf8b
3 changed files with 98 additions and 45 deletions

View File

@@ -91,27 +91,6 @@ static struct command_result *param_list_or_string(struct command *cmd,
return NULL;
}
/* Does k1 match k2 as far as k2 goes? */
static bool datastore_key_startswith(const char **k1, const char **k2)
{
size_t k1len = tal_count(k1), k2len = tal_count(k2);
if (k2len > k1len)
return false;
for (size_t i = 0; i < k2len; i++) {
if (!streq(k1[i], k2[i]))
return false;
}
return true;
}
static bool datastore_key_eq(const char **k1, const char **k2)
{
return tal_count(k1) == tal_count(k2)
&& datastore_key_startswith(k1, k2);
}
static char *datastore_key_fmt(const tal_t *ctx, const char **key)
{
char *ret = tal_strdup(ctx, "[");
@@ -180,16 +159,14 @@ static struct command_result *json_datastore(struct command *cmd,
for (size_t i = 1; i < tal_count(key); i++) {
const char **parent;
parent = tal_dup_arr(cmd, const char *, key, i, 0);
stmt = wallet_datastore_first(cmd, cmd->ld->wallet,
parent, &k, NULL, NULL);
tal_free(stmt);
if (stmt && datastore_key_eq(k, parent))
if (wallet_datastore_get(cmd, cmd->ld->wallet, parent,
NULL)) {
return command_fail(cmd,
DATASTORE_UPDATE_NO_CHILDREN,
"Parent key %s exists",
datastore_key_fmt(tmpctx,
parent));
}
}
}
@@ -252,13 +229,13 @@ static struct command_result *json_listdatastore(struct command *cmd,
for (stmt = wallet_datastore_first(cmd, cmd->ld->wallet, key,
&k, &data, &generation);
stmt;
stmt = wallet_datastore_next(cmd, cmd->ld->wallet,
stmt = wallet_datastore_next(cmd, key,
stmt, &k, &data,
&generation)) {
log_debug(cmd->ld->log, "Got %s",
datastore_key_fmt(tmpctx, k));
/* Don't list children, except implicitly */
/* Don't list sub-children, except as summary to show it exists. */
if (tal_count(k) > tal_count(key) + 1) {
log_debug(cmd->ld->log, "Too long");
if (!prev_k || !datastore_key_startswith(k, prev_k)) {
@@ -268,10 +245,6 @@ static struct command_result *json_listdatastore(struct command *cmd,
json_add_datastore(response, prev_k, NULL, 0);
json_object_end(response);
}
} else if (key && !datastore_key_startswith(k, key)) {
log_debug(cmd->ld->log, "Not interested");
tal_free(stmt);
break;
} else {
log_debug(cmd->ld->log, "Printing");
json_object_start(response, NULL);
@@ -289,11 +262,10 @@ static struct command_result *json_deldatastore(struct command *cmd,
const jsmntok_t *params)
{
struct json_stream *response;
const char **key, **k;
const char **key;
const u8 *data;
u64 *generation;
u64 actual_gen;
struct db_stmt *stmt;
if (!param(cmd, buffer, params,
p_req("key", param_list_or_string, &key),
@@ -301,11 +273,8 @@ static struct command_result *json_deldatastore(struct command *cmd,
NULL))
return command_param_failed();
stmt = wallet_datastore_first(cmd, cmd->ld->wallet, key,
&k, &data, &actual_gen);
tal_free(stmt);
if (!stmt || !datastore_key_eq(k, key)) {
data = wallet_datastore_get(cmd, cmd->ld->wallet, key, &actual_gen);
if (!data) {
return command_fail(cmd, DATASTORE_DEL_DOES_NOT_EXIST,
"Key does not exist");
}

View File

@@ -5333,8 +5333,67 @@ void wallet_datastore_remove(struct wallet *w, const char **key)
db_datastore_remove(w->db, key);
}
/* Does k1 match k2 as far as k2 goes? */
bool datastore_key_startswith(const char **k1, const char **k2)
{
size_t k1len = tal_count(k1), k2len = tal_count(k2);
if (k2len > k1len)
return false;
for (size_t i = 0; i < k2len; i++) {
if (!streq(k1[i], k2[i]))
return false;
}
return true;
}
bool datastore_key_eq(const char **k1, const char **k2)
{
return tal_count(k1) == tal_count(k2)
&& datastore_key_startswith(k1, k2);
}
static u8 *db_datastore_get(const tal_t *ctx,
struct db *db,
const char **key,
u64 *generation)
{
struct db_stmt *stmt;
u8 *ret;
stmt = db_prepare_v2(db,
SQL("SELECT data, generation"
" FROM datastore"
" WHERE key = ?"));
db_bind_datastore_key(stmt, key);
db_query_prepared(stmt);
if (!db_step(stmt)) {
tal_free(stmt);
return NULL;
}
ret = db_col_arr(ctx, stmt, "data", u8);
if (generation)
*generation = db_col_u64(stmt, "generation");
else
db_col_ignore(stmt, "generation");
tal_free(stmt);
return ret;
}
u8 *wallet_datastore_get(const tal_t *ctx,
struct wallet *w,
const char **key,
u64 *generation)
{
return db_datastore_get(ctx, w->db, key, generation);
}
static struct db_stmt *db_datastore_next(const tal_t *ctx,
struct db_stmt *stmt,
const char **startkey,
const char ***key,
const u8 **data,
u64 *generation)
@@ -5343,6 +5402,14 @@ static struct db_stmt *db_datastore_next(const tal_t *ctx,
return tal_free(stmt);
*key = db_col_datastore_key(ctx, stmt, "key");
/* We select from startkey onwards, so once we're past it, stop */
if (startkey && !datastore_key_startswith(*key, startkey)) {
db_col_ignore(stmt, "data");
db_col_ignore(stmt, "generation");
return tal_free(stmt);
}
if (data)
*data = db_col_arr(ctx, stmt, "data", u8);
else
@@ -5380,7 +5447,7 @@ static struct db_stmt *db_datastore_first(const tal_t *ctx,
}
db_query_prepared(stmt);
return db_datastore_next(ctx, stmt, key, data, generation);
return db_datastore_next(ctx, stmt, startkey, key, data, generation);
}
struct db_stmt *wallet_datastore_first(const tal_t *ctx,
@@ -5394,13 +5461,13 @@ struct db_stmt *wallet_datastore_first(const tal_t *ctx,
}
struct db_stmt *wallet_datastore_next(const tal_t *ctx,
struct wallet *w,
const char **startkey,
struct db_stmt *stmt,
const char ***key,
const u8 **data,
u64 *generation)
{
return db_datastore_next(ctx, stmt, key, data, generation);
return db_datastore_next(ctx, stmt, startkey, key, data, generation);
}
/* We use a different query form if we only care about a single channel. */

View File

@@ -1444,11 +1444,23 @@ void wallet_datastore_update(struct wallet *w,
*/
void wallet_datastore_remove(struct wallet *w, const char **key);
/**
* Get a single entry from the datastore
* @ctx: the tal ctx to allocate off
* @w: the wallet
* @key: the key
* @generation: the generation or NULL (set if returns non-NULL)
*/
u8 *wallet_datastore_get(const tal_t *ctx,
struct wallet *w,
const char **key,
u64 *generation);
/**
* Iterate through the datastore.
* @ctx: the tal ctx to allocate off
* @w: the wallet
* @startkey: NULL, or the first key to start with
* @startkey: NULL, or the subkey to iterate
* @key: the first key (if returns non-NULL)
* @data: the first data (if returns non-NULL)
* @generation: the first generation (if returns non-NULL)
@@ -1466,7 +1478,7 @@ struct db_stmt *wallet_datastore_first(const tal_t *ctx,
/**
* Iterate through the datastore.
* @ctx: the tal ctx to allocate off
* @w: the wallet
* @startkey: NULL, or the subkey to iterate
* @stmt: the previous statement.
* @key: the key (if returns non-NULL)
* @data: the data (if returns non-NULL)
@@ -1476,12 +1488,17 @@ struct db_stmt *wallet_datastore_first(const tal_t *ctx,
* If you choose not to call wallet_datastore_next() you must free it!
*/
struct db_stmt *wallet_datastore_next(const tal_t *ctx,
struct wallet *w,
const char **startkey,
struct db_stmt *stmt,
const char ***key,
const u8 **data,
u64 *generation);
/* Does k1 match k2 as far as k2 goes? */
bool datastore_key_startswith(const char **k1, const char **k2);
/* Does k1 match k2? */
bool datastore_key_eq(const char **k1, const char **k2);
/**
* Iterate through the htlcs table.
* @w: the wallet