From 0c4bbdf68c29c16887a169a8321e290008903817 Mon Sep 17 00:00:00 2001 From: s441433 Date: Fri, 28 Dec 2018 22:12:02 +0100 Subject: [PATCH] Create callback.go --- src/github.com/mattn/go-sqlite3/callback.go | 380 ++++++++++++++++++++ 1 file changed, 380 insertions(+) create mode 100644 src/github.com/mattn/go-sqlite3/callback.go diff --git a/src/github.com/mattn/go-sqlite3/callback.go b/src/github.com/mattn/go-sqlite3/callback.go new file mode 100644 index 0000000..e8c492b --- /dev/null +++ b/src/github.com/mattn/go-sqlite3/callback.go @@ -0,0 +1,380 @@ +// Copyright (C) 2014 Yasuhiro Matsumoto . +// +// Use of this source code is governed by an MIT-style +// license that can be found in the LICENSE file. + +package sqlite3 + +// You can't export a Go function to C and have definitions in the C +// preamble in the same file, so we have to have callbackTrampoline in +// its own file. Because we need a separate file anyway, the support +// code for SQLite custom functions is in here. + +/* +#ifndef USE_LIBSQLITE3 +#include +#else +#include +#endif +#include + +void _sqlite3_result_text(sqlite3_context* ctx, const char* s); +void _sqlite3_result_blob(sqlite3_context* ctx, const void* b, int l); +*/ +import "C" + +import ( + "errors" + "fmt" + "math" + "reflect" + "sync" + "unsafe" +) + +//export callbackTrampoline +func callbackTrampoline(ctx *C.sqlite3_context, argc int, argv **C.sqlite3_value) { + args := (*[(math.MaxInt32 - 1) / unsafe.Sizeof((*C.sqlite3_value)(nil))]*C.sqlite3_value)(unsafe.Pointer(argv))[:argc:argc] + fi := lookupHandle(uintptr(C.sqlite3_user_data(ctx))).(*functionInfo) + fi.Call(ctx, args) +} + +//export stepTrampoline +func stepTrampoline(ctx *C.sqlite3_context, argc C.int, argv **C.sqlite3_value) { + args := (*[(math.MaxInt32 - 1) / unsafe.Sizeof((*C.sqlite3_value)(nil))]*C.sqlite3_value)(unsafe.Pointer(argv))[:int(argc):int(argc)] + ai := lookupHandle(uintptr(C.sqlite3_user_data(ctx))).(*aggInfo) + ai.Step(ctx, args) +} + +//export doneTrampoline +func doneTrampoline(ctx *C.sqlite3_context) { + handle := uintptr(C.sqlite3_user_data(ctx)) + ai := lookupHandle(handle).(*aggInfo) + ai.Done(ctx) +} + +//export compareTrampoline +func compareTrampoline(handlePtr uintptr, la C.int, a *C.char, lb C.int, b *C.char) C.int { + cmp := lookupHandle(handlePtr).(func(string, string) int) + return C.int(cmp(C.GoStringN(a, la), C.GoStringN(b, lb))) +} + +//export commitHookTrampoline +func commitHookTrampoline(handle uintptr) int { + callback := lookupHandle(handle).(func() int) + return callback() +} + +//export rollbackHookTrampoline +func rollbackHookTrampoline(handle uintptr) { + callback := lookupHandle(handle).(func()) + callback() +} + +//export updateHookTrampoline +func updateHookTrampoline(handle uintptr, op int, db *C.char, table *C.char, rowid int64) { + callback := lookupHandle(handle).(func(int, string, string, int64)) + callback(op, C.GoString(db), C.GoString(table), rowid) +} + +//export authorizerTrampoline +func authorizerTrampoline(handle uintptr, op int, arg1 *C.char, arg2 *C.char, arg3 *C.char) int { + callback := lookupHandle(handle).(func(int, string, string, string) int) + return callback(op, C.GoString(arg1), C.GoString(arg2), C.GoString(arg3)) +} + +// Use handles to avoid passing Go pointers to C. + +type handleVal struct { + db *SQLiteConn + val interface{} +} + +var handleLock sync.Mutex +var handleVals = make(map[uintptr]handleVal) +var handleIndex uintptr = 100 + +func newHandle(db *SQLiteConn, v interface{}) uintptr { + handleLock.Lock() + defer handleLock.Unlock() + i := handleIndex + handleIndex++ + handleVals[i] = handleVal{db, v} + return i +} + +func lookupHandle(handle uintptr) interface{} { + handleLock.Lock() + defer handleLock.Unlock() + r, ok := handleVals[handle] + if !ok { + if handle >= 100 && handle < handleIndex { + panic("deleted handle") + } else { + panic("invalid handle") + } + } + return r.val +} + +func deleteHandles(db *SQLiteConn) { + handleLock.Lock() + defer handleLock.Unlock() + for handle, val := range handleVals { + if val.db == db { + delete(handleVals, handle) + } + } +} + +// This is only here so that tests can refer to it. +type callbackArgRaw C.sqlite3_value + +type callbackArgConverter func(*C.sqlite3_value) (reflect.Value, error) + +type callbackArgCast struct { + f callbackArgConverter + typ reflect.Type +} + +func (c callbackArgCast) Run(v *C.sqlite3_value) (reflect.Value, error) { + val, err := c.f(v) + if err != nil { + return reflect.Value{}, err + } + if !val.Type().ConvertibleTo(c.typ) { + return reflect.Value{}, fmt.Errorf("cannot convert %s to %s", val.Type(), c.typ) + } + return val.Convert(c.typ), nil +} + +func callbackArgInt64(v *C.sqlite3_value) (reflect.Value, error) { + if C.sqlite3_value_type(v) != C.SQLITE_INTEGER { + return reflect.Value{}, fmt.Errorf("argument must be an INTEGER") + } + return reflect.ValueOf(int64(C.sqlite3_value_int64(v))), nil +} + +func callbackArgBool(v *C.sqlite3_value) (reflect.Value, error) { + if C.sqlite3_value_type(v) != C.SQLITE_INTEGER { + return reflect.Value{}, fmt.Errorf("argument must be an INTEGER") + } + i := int64(C.sqlite3_value_int64(v)) + val := false + if i != 0 { + val = true + } + return reflect.ValueOf(val), nil +} + +func callbackArgFloat64(v *C.sqlite3_value) (reflect.Value, error) { + if C.sqlite3_value_type(v) != C.SQLITE_FLOAT { + return reflect.Value{}, fmt.Errorf("argument must be a FLOAT") + } + return reflect.ValueOf(float64(C.sqlite3_value_double(v))), nil +} + +func callbackArgBytes(v *C.sqlite3_value) (reflect.Value, error) { + switch C.sqlite3_value_type(v) { + case C.SQLITE_BLOB: + l := C.sqlite3_value_bytes(v) + p := C.sqlite3_value_blob(v) + return reflect.ValueOf(C.GoBytes(p, l)), nil + case C.SQLITE_TEXT: + l := C.sqlite3_value_bytes(v) + c := unsafe.Pointer(C.sqlite3_value_text(v)) + return reflect.ValueOf(C.GoBytes(c, l)), nil + default: + return reflect.Value{}, fmt.Errorf("argument must be BLOB or TEXT") + } +} + +func callbackArgString(v *C.sqlite3_value) (reflect.Value, error) { + switch C.sqlite3_value_type(v) { + case C.SQLITE_BLOB: + l := C.sqlite3_value_bytes(v) + p := (*C.char)(C.sqlite3_value_blob(v)) + return reflect.ValueOf(C.GoStringN(p, l)), nil + case C.SQLITE_TEXT: + c := (*C.char)(unsafe.Pointer(C.sqlite3_value_text(v))) + return reflect.ValueOf(C.GoString(c)), nil + default: + return reflect.Value{}, fmt.Errorf("argument must be BLOB or TEXT") + } +} + +func callbackArgGeneric(v *C.sqlite3_value) (reflect.Value, error) { + switch C.sqlite3_value_type(v) { + case C.SQLITE_INTEGER: + return callbackArgInt64(v) + case C.SQLITE_FLOAT: + return callbackArgFloat64(v) + case C.SQLITE_TEXT: + return callbackArgString(v) + case C.SQLITE_BLOB: + return callbackArgBytes(v) + case C.SQLITE_NULL: + // Interpret NULL as a nil byte slice. + var ret []byte + return reflect.ValueOf(ret), nil + default: + panic("unreachable") + } +} + +func callbackArg(typ reflect.Type) (callbackArgConverter, error) { + switch typ.Kind() { + case reflect.Interface: + if typ.NumMethod() != 0 { + return nil, errors.New("the only supported interface type is interface{}") + } + return callbackArgGeneric, nil + case reflect.Slice: + if typ.Elem().Kind() != reflect.Uint8 { + return nil, errors.New("the only supported slice type is []byte") + } + return callbackArgBytes, nil + case reflect.String: + return callbackArgString, nil + case reflect.Bool: + return callbackArgBool, nil + case reflect.Int64: + return callbackArgInt64, nil + case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Int, reflect.Uint: + c := callbackArgCast{callbackArgInt64, typ} + return c.Run, nil + case reflect.Float64: + return callbackArgFloat64, nil + case reflect.Float32: + c := callbackArgCast{callbackArgFloat64, typ} + return c.Run, nil + default: + return nil, fmt.Errorf("don't know how to convert to %s", typ) + } +} + +func callbackConvertArgs(argv []*C.sqlite3_value, converters []callbackArgConverter, variadic callbackArgConverter) ([]reflect.Value, error) { + var args []reflect.Value + + if len(argv) < len(converters) { + return nil, fmt.Errorf("function requires at least %d arguments", len(converters)) + } + + for i, arg := range argv[:len(converters)] { + v, err := converters[i](arg) + if err != nil { + return nil, err + } + args = append(args, v) + } + + if variadic != nil { + for _, arg := range argv[len(converters):] { + v, err := variadic(arg) + if err != nil { + return nil, err + } + args = append(args, v) + } + } + return args, nil +} + +type callbackRetConverter func(*C.sqlite3_context, reflect.Value) error + +func callbackRetInteger(ctx *C.sqlite3_context, v reflect.Value) error { + switch v.Type().Kind() { + case reflect.Int64: + case reflect.Int8, reflect.Int16, reflect.Int32, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Int, reflect.Uint: + v = v.Convert(reflect.TypeOf(int64(0))) + case reflect.Bool: + b := v.Interface().(bool) + if b { + v = reflect.ValueOf(int64(1)) + } else { + v = reflect.ValueOf(int64(0)) + } + default: + return fmt.Errorf("cannot convert %s to INTEGER", v.Type()) + } + + C.sqlite3_result_int64(ctx, C.sqlite3_int64(v.Interface().(int64))) + return nil +} + +func callbackRetFloat(ctx *C.sqlite3_context, v reflect.Value) error { + switch v.Type().Kind() { + case reflect.Float64: + case reflect.Float32: + v = v.Convert(reflect.TypeOf(float64(0))) + default: + return fmt.Errorf("cannot convert %s to FLOAT", v.Type()) + } + + C.sqlite3_result_double(ctx, C.double(v.Interface().(float64))) + return nil +} + +func callbackRetBlob(ctx *C.sqlite3_context, v reflect.Value) error { + if v.Type().Kind() != reflect.Slice || v.Type().Elem().Kind() != reflect.Uint8 { + return fmt.Errorf("cannot convert %s to BLOB", v.Type()) + } + i := v.Interface() + if i == nil || len(i.([]byte)) == 0 { + C.sqlite3_result_null(ctx) + } else { + bs := i.([]byte) + C._sqlite3_result_blob(ctx, unsafe.Pointer(&bs[0]), C.int(len(bs))) + } + return nil +} + +func callbackRetText(ctx *C.sqlite3_context, v reflect.Value) error { + if v.Type().Kind() != reflect.String { + return fmt.Errorf("cannot convert %s to TEXT", v.Type()) + } + C._sqlite3_result_text(ctx, C.CString(v.Interface().(string))) + return nil +} + +func callbackRetNil(ctx *C.sqlite3_context, v reflect.Value) error { + return nil +} + +func callbackRet(typ reflect.Type) (callbackRetConverter, error) { + switch typ.Kind() { + case reflect.Interface: + errorInterface := reflect.TypeOf((*error)(nil)).Elem() + if typ.Implements(errorInterface) { + return callbackRetNil, nil + } + fallthrough + case reflect.Slice: + if typ.Elem().Kind() != reflect.Uint8 { + return nil, errors.New("the only supported slice type is []byte") + } + return callbackRetBlob, nil + case reflect.String: + return callbackRetText, nil + case reflect.Bool, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Int, reflect.Uint: + return callbackRetInteger, nil + case reflect.Float32, reflect.Float64: + return callbackRetFloat, nil + default: + return nil, fmt.Errorf("don't know how to convert to %s", typ) + } +} + +func callbackError(ctx *C.sqlite3_context, err error) { + cstr := C.CString(err.Error()) + defer C.free(unsafe.Pointer(cstr)) + C.sqlite3_result_error(ctx, cstr, C.int(-1)) +} + +// Test support code. Tests are not allowed to import "C", so we can't +// declare any functions that use C.sqlite3_value. +func callbackSyntheticForTests(v reflect.Value, err error) callbackArgConverter { + return func(*C.sqlite3_value) (reflect.Value, error) { + return v, err + } +}