Merge pull request #347 from DataDog/dd/vtable

Add Go API for virtual tables

1 files changed, 182 insertions, 0 deletions

diff --git a/vtable.c b/vtable.c
new file mode 100644
index 0000000..e1d7575
--- /dev/null
+++ b/vtable.c
@@ -0,0 +1,182 @@
+// Copyright (C) 2014 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+#ifndef USE_LIBSQLITE3
+#include <sqlite3-binding.h>
+#else
+#include <sqlite3.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#include <stdint.h>
+#include "_cgo_export.h"
+
+
+typedef struct goVTab goVTab;
+
+struct goVTab {
+	sqlite3_vtab base;
+	void *vTab;
+};
+
+static int cXInit(sqlite3 *db, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char **pzErr, int isCreate) {
+	void *vTab = (void *)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) {
+	char *pzErr = goVBestIndex(((goVTab*)pVTab)->vTab, info);
+	if (pzErr) {
+		if (pVTab->zErrMsg)
+			sqlite3_free(pVTab->zErrMsg);
+		pVTab->zErrMsg = pzErr;
+		return SQLITE_ERROR;
+	}
+	return SQLITE_OK;
+}
+
+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;
+};
+
+static int cXOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor) {
+	void *vTabCursor = (void *)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;
+}
+
+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;
+}
+
+static int cXFilter(sqlite3_vtab_cursor *pCursor, int idxNum, const char *idxStr, int argc, sqlite3_value **argv) {
+	char *pzErr = goVFilter(((goVTabCursor*)pCursor)->vTabCursor, idxNum, (char*)idxStr, argc, argv);
+	if (pzErr) {
+		return setErrMsg(pCursor, pzErr);
+	}
+	return SQLITE_OK;
+}
+
+static int cXNext(sqlite3_vtab_cursor *pCursor) {
+	char *pzErr = goVNext(((goVTabCursor*)pCursor)->vTabCursor);
+	if (pzErr) {
+		return setErrMsg(pCursor, pzErr);
+	}
+	return SQLITE_OK;
+}
+
+static inline int cXEof(sqlite3_vtab_cursor *pCursor) {
+	return goVEof(((goVTabCursor*)pCursor)->vTabCursor);
+}
+
+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;
+}
+
+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 */
+// Not implemented
+	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 */
+};
+
+
+int goSqlite3CreateModule(sqlite3 *db, const char *zName, uintptr_t pClientData) {
+	return sqlite3_create_module_v2(db, zName, &goModule, (void*) pClientData, goMDestroy);
+}
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