--- a/dbd/postgresql/statement.c Sun Nov 23 01:29:09 2008 +0000
+++ b/dbd/postgresql/statement.c Sun Nov 23 04:12:04 2008 +0000
@@ -1,6 +1,6 @@
#include "dbd_postgresql.h"
-#define MAX_PLACEHOLDERS 9999
+#define MAX_PLACEHOLDERS 9999
#define MAX_PLACEHOLDER_SIZE (1+4) /* $\d{4} */
static lua_push_type_t postgresql_to_lua_push(unsigned int postgresql_type) {
@@ -28,6 +28,10 @@
return lua_type;
}
+/*
+ * replace '?' placeholders with $\d+ placeholders
+ * to be compatible with PSQL API
+ */
static char *replace_placeholders(lua_State *L, const char *sql) {
size_t len = strlen(sql);
int num_placeholders = 0;
@@ -38,20 +42,43 @@
int ph_num = 1;
int in_quote = 0;
+ /*
+ * dumb count of all '?'
+ * this will match more placeholders than necessesary
+ * but it's safer to allocate more placeholders at the
+ * cost of a few bytes than risk a buffer overflow
+ */
for (i = 1; i < len; i++) {
if (sql[i] == '?') {
num_placeholders++;
}
}
+ /*
+ * this is MAX_PLACEHOLDER_SIZE-1 because the '?' is
+ * replaced with '$'
+ */
extra_space = num_placeholders * (MAX_PLACEHOLDER_SIZE-1);
+ /*
+ * allocate a new string for the converted SQL statement
+ */
newsql = malloc(sizeof(char) * (len+extra_space+1));
memset(newsql, 0, sizeof(char) * (len+extra_space+1));
- /* copy first char */
+ /*
+ * copy first char. In valid SQL this cannot be a placeholder
+ */
newsql[0] = sql[0];
+
+ /*
+ * only replace '?' not in a single quoted string
+ */
for (i = 1; i < len; i++) {
+ /*
+ * don't change the quote flag if the ''' is preceded
+ * bt a '\' to account for escaping
+ */
if (sql[i] == '\'' && sql[i-1] != '\\') {
in_quote = !in_quote;
}
@@ -72,13 +99,18 @@
}
}
- /* terminate string on the last position */
+ /*
+ * terminate string on the last position
+ */
newsql[newpos] = '\0';
/* fprintf(stderr, "[%s]\n", newsql); */
return newsql;
}
+/*
+ * success = statement:close()
+ */
static int statement_close(lua_State *L) {
statement_t *statement = (statement_t *)luaL_checkudata(L, 1, DBD_POSTGRESQL_STATEMENT);
@@ -90,6 +122,9 @@
return 0;
}
+/*
+ * success = statement:execute(...)
+ */
static int statement_execute(lua_State *L) {
int n = lua_gettop(L);
statement_t *statement = (statement_t *)luaL_checkudata(L, 1, DBD_POSTGRESQL_STATEMENT);
@@ -104,6 +139,9 @@
params = malloc(num_bind_params * sizeof(params));
+ /*
+ * convert and copy parameters into a string array
+ */
for (p = 2; p <= n; p++) {
int i = p - 2;
@@ -131,6 +169,9 @@
0
);
+ /*
+ * free string array
+ */
for (p = 0; p < num_bind_params; p++) {
if (params[p]) {
free(params[p]);
@@ -157,6 +198,9 @@
return 1;
}
+/*
+ * must be called after an execute
+ */
static int statement_fetch_impl(lua_State *L, int named_columns) {
statement_t *statement = (statement_t *)luaL_checkudata(L, 1, DBD_POSTGRESQL_STATEMENT);
int tuple = statement->tuple++;
@@ -189,6 +233,10 @@
const char *value = PQgetvalue(statement->result, tuple, i);
lua_push_type_t lua_push = postgresql_to_lua_push(PQftype(statement->result, i));
+ /*
+ * data is returned as strings from PSQL
+ */
+
if (lua_push == LUA_PUSH_NIL) {
if (named_columns) {
LUA_PUSH_ATTRIB_NIL(name);
@@ -218,6 +266,10 @@
LUA_PUSH_ARRAY_STRING(d, value);
}
} else if (lua_push == LUA_PUSH_BOOLEAN) {
+ /*
+ * booleans are returned as a string
+ * either 't' or 'f'
+ */
int val = value[0] == 't' ? 1 : 0;
if (named_columns) {
@@ -234,15 +286,23 @@
return 1;
}
-
+/*
+ * array = statement:fetch()
+ */
static int statement_fetch(lua_State *L) {
return statement_fetch_impl(L, 0);
}
+/*
+ * hashmap = statement:fetchtable()
+ */
static int statement_fetchtable(lua_State *L) {
return statement_fetch_impl(L, 1);
}
+/*
+ * __gc
+ */
static int statement_gc(lua_State *L) {
/* always free the handle */
statement_close(L);
@@ -250,19 +310,6 @@
return 0;
}
-
-static const luaL_Reg statement_methods[] = {
- {"close", statement_close},
- {"execute", statement_execute},
- {"fetch", statement_fetch},
- {"fetchtable", statement_fetchtable},
- {NULL, NULL}
-};
-
-static const luaL_Reg statement_class_methods[] = {
- {NULL, NULL}
-};
-
int dbd_postgresql_statement_create(lua_State *L, connection_t *conn, const char *sql_query) {
statement_t *statement = NULL;
ExecStatusType status;
@@ -270,11 +317,18 @@
char *new_sql;
char name[IDLEN];
+ /*
+ * convert SQL string into a PSQL API compatible SQL statement
+ */
new_sql = replace_placeholders(L, sql_query);
snprintf(name, IDLEN, "%017u", ++conn->statement_id);
result = PQprepare(conn->postgresql, name, new_sql, 0, NULL);
+
+ /*
+ * free converted statement after use
+ */
free(new_sql);
if (!result) {
@@ -305,6 +359,18 @@
}
int dbd_postgresql_statement(lua_State *L) {
+ static const luaL_Reg statement_methods[] = {
+ {"close", statement_close},
+ {"execute", statement_execute},
+ {"fetch", statement_fetch},
+ {"fetchtable", statement_fetchtable},
+ {NULL, NULL}
+ };
+
+ static const luaL_Reg statement_class_methods[] = {
+ {NULL, NULL}
+ };
+
luaL_newmetatable(L, DBD_POSTGRESQL_STATEMENT);
luaL_register(L, 0, statement_methods);
lua_pushvalue(L,-1);