mirror of
https://github.com/tursodatabase/libsql.git
synced 2024-11-27 06:58:59 +00:00
126 lines
3.4 KiB
C
126 lines
3.4 KiB
C
/*
|
|
** 2014-11-10
|
|
**
|
|
** The author disclaims copyright to this source code. In place of
|
|
** a legal notice, here is a blessing:
|
|
**
|
|
** May you do good and not evil.
|
|
** May you find forgiveness for yourself and forgive others.
|
|
** May you share freely, never taking more than you give.
|
|
**
|
|
******************************************************************************
|
|
**
|
|
** This SQLite extension implements SQL function eval() which runs
|
|
** SQL statements recursively.
|
|
*/
|
|
#include "sqlite3ext.h"
|
|
SQLITE_EXTENSION_INIT1
|
|
#include <string.h>
|
|
|
|
/*
|
|
** Structure used to accumulate the output
|
|
*/
|
|
struct EvalResult {
|
|
char *z; /* Accumulated output */
|
|
const char *zSep; /* Separator */
|
|
int szSep; /* Size of the separator string */
|
|
sqlite3_int64 nAlloc; /* Number of bytes allocated for z[] */
|
|
sqlite3_int64 nUsed; /* Number of bytes of z[] actually used */
|
|
};
|
|
|
|
/*
|
|
** Callback from sqlite_exec() for the eval() function.
|
|
*/
|
|
static int callback(void *pCtx, int argc, char **argv, char **colnames){
|
|
struct EvalResult *p = (struct EvalResult*)pCtx;
|
|
int i;
|
|
if( argv==0 ) return 0;
|
|
for(i=0; i<argc; i++){
|
|
const char *z = argv[i] ? argv[i] : "";
|
|
size_t sz = strlen(z);
|
|
if( (sqlite3_int64)sz+p->nUsed+p->szSep+1 > p->nAlloc ){
|
|
char *zNew;
|
|
p->nAlloc = p->nAlloc*2 + sz + p->szSep + 1;
|
|
/* Using sqlite3_realloc64() would be better, but it is a recent
|
|
** addition and will cause a segfault if loaded by an older version
|
|
** of SQLite. */
|
|
zNew = p->nAlloc<=0x7fffffff ? sqlite3_realloc64(p->z, p->nAlloc) : 0;
|
|
if( zNew==0 ){
|
|
sqlite3_free(p->z);
|
|
memset(p, 0, sizeof(*p));
|
|
return 1;
|
|
}
|
|
p->z = zNew;
|
|
}
|
|
if( p->nUsed>0 ){
|
|
memcpy(&p->z[p->nUsed], p->zSep, p->szSep);
|
|
p->nUsed += p->szSep;
|
|
}
|
|
memcpy(&p->z[p->nUsed], z, sz);
|
|
p->nUsed += sz;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
** Implementation of the eval(X) and eval(X,Y) SQL functions.
|
|
**
|
|
** Evaluate the SQL text in X. Return the results, using string
|
|
** Y as the separator. If Y is omitted, use a single space character.
|
|
*/
|
|
static void sqlEvalFunc(
|
|
sqlite3_context *context,
|
|
int argc,
|
|
sqlite3_value **argv
|
|
){
|
|
const char *zSql;
|
|
sqlite3 *db;
|
|
char *zErr = 0;
|
|
int rc;
|
|
struct EvalResult x;
|
|
|
|
memset(&x, 0, sizeof(x));
|
|
x.zSep = " ";
|
|
zSql = (const char*)sqlite3_value_text(argv[0]);
|
|
if( zSql==0 ) return;
|
|
if( argc>1 ){
|
|
x.zSep = (const char*)sqlite3_value_text(argv[1]);
|
|
if( x.zSep==0 ) return;
|
|
}
|
|
x.szSep = (int)strlen(x.zSep);
|
|
db = sqlite3_context_db_handle(context);
|
|
rc = sqlite3_exec(db, zSql, callback, &x, &zErr);
|
|
if( rc!=SQLITE_OK ){
|
|
sqlite3_result_error(context, zErr, -1);
|
|
sqlite3_free(zErr);
|
|
}else if( x.zSep==0 ){
|
|
sqlite3_result_error_nomem(context);
|
|
sqlite3_free(x.z);
|
|
}else{
|
|
sqlite3_result_text(context, x.z, (int)x.nUsed, sqlite3_free);
|
|
}
|
|
}
|
|
|
|
|
|
#ifdef _WIN32
|
|
__declspec(dllexport)
|
|
#endif
|
|
int sqlite3_eval_init(
|
|
sqlite3 *db,
|
|
char **pzErrMsg,
|
|
const sqlite3_api_routines *pApi
|
|
){
|
|
int rc = SQLITE_OK;
|
|
SQLITE_EXTENSION_INIT2(pApi);
|
|
(void)pzErrMsg; /* Unused parameter */
|
|
rc = sqlite3_create_function(db, "eval", 1,
|
|
SQLITE_UTF8|SQLITE_DIRECTONLY, 0,
|
|
sqlEvalFunc, 0, 0);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3_create_function(db, "eval", 2,
|
|
SQLITE_UTF8|SQLITE_DIRECTONLY, 0,
|
|
sqlEvalFunc, 0, 0);
|
|
}
|
|
return rc;
|
|
}
|