vtab.c

// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

#include <sqlite3.h>
#include <string.h>

typedef struct goVTab goVTab;

struct goVTab {
	sqlite3_vtab base;
	void *vTab;
};

extern void* goMInit(void *db, void *pAux, int argc, char **argv, char **pzErr, int isCreate);

static int cXInit(sqlite3 *db, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char **pzErr, int isCreate) {
	void *vTab = goMInit(db, pAux, argc, (char**)argv, pzErr, isCreate);
	if (!vTab || *pzErr) {
		return SQLITE_ERROR;
	}
	goVTab *pvTab = (goVTab *)sqlite3_malloc(sizeof(goVTab));
	if (!pvTab) {
		*pzErr = sqlite3_mprintf("%s", "Out of memory");
		return SQLITE_NOMEM;
	}
	memset(pvTab, 0, sizeof(goVTab));
	pvTab->vTab = vTab;

	*ppVTab = (sqlite3_vtab *)pvTab;
	*pzErr = 0;
	return SQLITE_OK;
}

static inline int cXCreate(sqlite3 *db, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char **pzErr) {
	return cXInit(db, pAux, argc, argv, ppVTab, pzErr, 1);
}
static inline int cXConnect(sqlite3 *db, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char **pzErr) {
	return cXInit(db, pAux, argc, argv, ppVTab, pzErr, 0);
}

static inline int cXBestIndex(sqlite3_vtab *pVTab, sqlite3_index_info *info) {
	// TODO
	return SQLITE_OK;
}

extern char* goVRelease(void *pVTab, int isDestroy);

static int cXRelease(sqlite3_vtab *pVTab, int isDestroy) {
	char *pzErr = goVRelease(((goVTab*)pVTab)->vTab, isDestroy);
	if (pzErr) {
		if (pVTab->zErrMsg)
			sqlite3_free(pVTab->zErrMsg);
		pVTab->zErrMsg = pzErr;
		return SQLITE_ERROR;
	}
	if (pVTab->zErrMsg)
		sqlite3_free(pVTab->zErrMsg);
	sqlite3_free(pVTab);
	return SQLITE_OK;
}

static inline int cXDisconnect(sqlite3_vtab *pVTab) {
	return cXRelease(pVTab, 0);
}
static inline int cXDestroy(sqlite3_vtab *pVTab) {
	return cXRelease(pVTab, 1);
}

typedef struct goVTabCursor goVTabCursor;

struct goVTabCursor {
	sqlite3_vtab_cursor base;
	void *vTabCursor;
};

extern void* goVOpen(void *pVTab, char **pzErr);

static int cXOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor) {
	void *vTabCursor = goVOpen(((goVTab*)pVTab)->vTab, &(pVTab->zErrMsg));
	goVTabCursor *pCursor = (goVTabCursor *)sqlite3_malloc(sizeof(goVTabCursor));
	if (!pCursor) {
		return SQLITE_NOMEM;
	}
	memset(pCursor, 0, sizeof(goVTabCursor));
	pCursor->vTabCursor = vTabCursor;
	*ppCursor = (sqlite3_vtab_cursor *)pCursor;
	return SQLITE_OK;
}

static int setErrMsg(sqlite3_vtab_cursor *pCursor, char *pzErr) {
	if (pCursor->pVtab->zErrMsg)
		sqlite3_free(pCursor->pVtab->zErrMsg);
	pCursor->pVtab->zErrMsg = pzErr;
	return SQLITE_ERROR;
}

extern char* goVClose(void *pCursor);

static int cXClose(sqlite3_vtab_cursor *pCursor) {
	char *pzErr = goVClose(((goVTabCursor*)pCursor)->vTabCursor);
	if (pzErr) {
		return setErrMsg(pCursor, pzErr);
	}
	sqlite3_free(pCursor);
	return SQLITE_OK;
}

extern char* goVFilter(void *pCursor);

static int cXFilter(sqlite3_vtab_cursor *pCursor, int idxNum, const char *idxStr, int argc, sqlite3_value **argv) {
	// TODO idxNum, idxStr, argc, argv are useless when cXBestIndex is empty
	char *pzErr = goVFilter(((goVTabCursor*)pCursor)->vTabCursor);
	if (pzErr) {
		return setErrMsg(pCursor, pzErr);
	}
	return SQLITE_OK;
}

extern char* goVNext(void *pCursor);

static int cXNext(sqlite3_vtab_cursor *pCursor) {
	char *pzErr = goVNext(((goVTabCursor*)pCursor)->vTabCursor);
	if (pzErr) {
		return setErrMsg(pCursor, pzErr);
	}
	return SQLITE_OK;
}

extern int goVEof(void *pCursor);

static inline int cXEof(sqlite3_vtab_cursor *pCursor) {
	return goVEof(((goVTabCursor*)pCursor)->vTabCursor);
}

extern char* goVColumn(void *pCursor, void *cp, int col);

static int cXColumn(sqlite3_vtab_cursor *pCursor, sqlite3_context *ctx, int i) {
	char *pzErr = goVColumn(((goVTabCursor*)pCursor)->vTabCursor, ctx, i);
	if (pzErr) {
		return setErrMsg(pCursor, pzErr);
	}
	return SQLITE_OK;
}

extern char* goVRowid(void *pCursor, sqlite3_int64 *pRowid);

static int cXRowid(sqlite3_vtab_cursor *pCursor, sqlite3_int64 *pRowid) {
	char *pzErr = goVRowid(((goVTabCursor*)pCursor)->vTabCursor, pRowid);
	if (pzErr) {
		return setErrMsg(pCursor, pzErr);
	}
	return SQLITE_OK;
}

static sqlite3_module goModule = {
	0,                       /* iVersion */
	cXCreate,                /* xCreate - create a table */
	cXConnect,               /* xConnect - connect to an existing table */
	cXBestIndex,             /* xBestIndex - Determine search strategy */
	cXDisconnect,            /* xDisconnect - Disconnect from a table */
	cXDestroy,               /* xDestroy - Drop a table */
	cXOpen,                  /* xOpen - open a cursor */
	cXClose,                 /* xClose - close a cursor */
	cXFilter,                /* xFilter - configure scan constraints */
	cXNext,                  /* xNext - advance a cursor */
	cXEof,                   /* xEof */
	cXColumn,                /* xColumn - read data */
	cXRowid,                 /* xRowid - read data */
// TODO
	0,                       /* xUpdate - write data */
	0,                       /* xBegin - begin transaction */
	0,                       /* xSync - sync transaction */
	0,                       /* xCommit - commit transaction */
	0,                       /* xRollback - rollback transaction */
	0,                       /* xFindFunction - function overloading */
	0,                       /* xRename - rename the table */
	0,                       /* xSavepoint */
	0,                       /* xRelease */
	0	                       /* xRollbackTo */
};

extern void goMDestroy(void*);

int goSqlite3CreateModule(sqlite3 *db, const char *zName, void *pClientData) {
	return sqlite3_create_module_v2(db, zName, &goModule, pClientData, goMDestroy);
}