diff --git a/sqlite3.go b/sqlite3.go index 7e56410..a931735 100644 --- a/sqlite3.go +++ b/sqlite3.go @@ -100,6 +100,8 @@ int _sqlite3_create_function( } void callbackTrampoline(sqlite3_context*, int, sqlite3_value**); +void stepTrampoline(sqlite3_context*, int, sqlite3_value**); +void doneTrampoline(sqlite3_context*); int compareTrampoline(void*, int, char*, int, char*); int commitHookTrampoline(void*); @@ -503,6 +505,131 @@ func sqlite3CreateFunction(db *C.sqlite3, zFunctionName *C.char, nArg C.int, eTe return C._sqlite3_create_function(db, zFunctionName, nArg, eTextRep, C.uintptr_t(pApp), (*[0]byte)(unsafe.Pointer(xFunc)), (*[0]byte)(unsafe.Pointer(xStep)), (*[0]byte)(unsafe.Pointer(xFinal))) } +// RegisterAggregator makes a Go type available as a SQLite aggregation function. +// +// Because aggregation is incremental, it's implemented in Go with a +// type that has 2 methods: func Step(values) accumulates one row of +// data into the accumulator, and func Done() ret finalizes and +// returns the aggregate value. "values" and "ret" may be any type +// supported by RegisterFunc. +// +// RegisterAggregator takes as implementation a constructor function +// that constructs an instance of the aggregator type each time an +// aggregation begins. The constructor must return a pointer to a +// type, or an interface that implements Step() and Done(). +// +// The constructor function and the Step/Done methods may optionally +// return an error in addition to their other return values. +// +// See _example/go_custom_funcs for a detailed example. +func (c *SQLiteConn) RegisterAggregator(name string, impl interface{}, pure bool) error { + var ai aggInfo + ai.constructor = reflect.ValueOf(impl) + t := ai.constructor.Type() + if t.Kind() != reflect.Func { + return errors.New("non-function passed to RegisterAggregator") + } + if t.NumOut() != 1 && t.NumOut() != 2 { + return errors.New("SQLite aggregator constructors must return 1 or 2 values") + } + if t.NumOut() == 2 && !t.Out(1).Implements(reflect.TypeOf((*error)(nil)).Elem()) { + return errors.New("Second return value of SQLite function must be error") + } + if t.NumIn() != 0 { + return errors.New("SQLite aggregator constructors must not have arguments") + } + + agg := t.Out(0) + switch agg.Kind() { + case reflect.Ptr, reflect.Interface: + default: + return errors.New("SQlite aggregator constructor must return a pointer object") + } + stepFn, found := agg.MethodByName("Step") + if !found { + return errors.New("SQlite aggregator doesn't have a Step() function") + } + step := stepFn.Type + if step.NumOut() != 0 && step.NumOut() != 1 { + return errors.New("SQlite aggregator Step() function must return 0 or 1 values") + } + if step.NumOut() == 1 && !step.Out(0).Implements(reflect.TypeOf((*error)(nil)).Elem()) { + return errors.New("type of SQlite aggregator Step() return value must be error") + } + + stepNArgs := step.NumIn() + start := 0 + if agg.Kind() == reflect.Ptr { + // Skip over the method receiver + stepNArgs-- + start++ + } + if step.IsVariadic() { + stepNArgs-- + } + for i := start; i < start+stepNArgs; i++ { + conv, err := callbackArg(step.In(i)) + if err != nil { + return err + } + ai.stepArgConverters = append(ai.stepArgConverters, conv) + } + if step.IsVariadic() { + conv, err := callbackArg(t.In(start + stepNArgs).Elem()) + if err != nil { + return err + } + ai.stepVariadicConverter = conv + // Pass -1 to sqlite so that it allows any number of + // arguments. The call helper verifies that the minimum number + // of arguments is present for variadic functions. + stepNArgs = -1 + } + + doneFn, found := agg.MethodByName("Done") + if !found { + return errors.New("SQlite aggregator doesn't have a Done() function") + } + done := doneFn.Type + doneNArgs := done.NumIn() + if agg.Kind() == reflect.Ptr { + // Skip over the method receiver + doneNArgs-- + } + if doneNArgs != 0 { + return errors.New("SQlite aggregator Done() function must have no arguments") + } + if done.NumOut() != 1 && done.NumOut() != 2 { + return errors.New("SQLite aggregator Done() function must return 1 or 2 values") + } + if done.NumOut() == 2 && !done.Out(1).Implements(reflect.TypeOf((*error)(nil)).Elem()) { + return errors.New("second return value of SQLite aggregator Done() function must be error") + } + + conv, err := callbackRet(done.Out(0)) + if err != nil { + return err + } + ai.doneRetConverter = conv + ai.active = make(map[int64]reflect.Value) + ai.next = 1 + + // ai must outlast the database connection, or we'll have dangling pointers. + c.aggregators = append(c.aggregators, &ai) + + cname := C.CString(name) + defer C.free(unsafe.Pointer(cname)) + opts := C.SQLITE_UTF8 + if pure { + opts |= C.SQLITE_DETERMINISTIC + } + rv := sqlite3CreateFunction(c.db, cname, C.int(stepNArgs), C.int(opts), newHandle(c, &ai), nil, C.stepTrampoline, C.doneTrampoline) + if rv != C.SQLITE_OK { + return c.lastError() + } + return nil +} + // AutoCommit return which currently auto commit or not. func (c *SQLiteConn) AutoCommit() bool { return int(C.sqlite3_get_autocommit(c.db)) != 0 diff --git a/sqlite3_test.go b/sqlite3_test.go index 9d4b373..84ecb5a 100644 --- a/sqlite3_test.go +++ b/sqlite3_test.go @@ -1232,6 +1232,66 @@ func TestFunctionRegistration(t *testing.T) { } } +type sumAggregator int64 + +func (s *sumAggregator) Step(x int64) { + *s += sumAggregator(x) +} + +func (s *sumAggregator) Done() int64 { + return int64(*s) +} + +func TestAggregatorRegistration(t *testing.T) { + customSum := func() *sumAggregator { + var ret sumAggregator + return &ret + } + + sql.Register("sqlite3_AggregatorRegistration", &SQLiteDriver{ + ConnectHook: func(conn *SQLiteConn) error { + if err := conn.RegisterAggregator("customSum", customSum, true); err != nil { + return err + } + return nil + }, + }) + db, err := sql.Open("sqlite3_AggregatorRegistration", ":memory:") + if err != nil { + t.Fatal("Failed to open database:", err) + } + defer db.Close() + + _, err = db.Exec("create table foo (department integer, profits integer)") + if err != nil { + // trace feature is not implemented + t.Skip("Failed to create table:", err) + } + + _, err = db.Exec("insert into foo values (1, 10), (1, 20), (2, 42)") + if err != nil { + t.Fatal("Failed to insert records:", err) + } + + tests := []struct { + dept, sum int64 + }{ + {1, 30}, + {2, 42}, + } + + for _, test := range tests { + var ret int64 + err = db.QueryRow("select customSum(profits) from foo where department = $1 group by department", test.dept).Scan(&ret) + if err != nil { + t.Fatal("Query failed:", err) + } + if ret != test.sum { + t.Fatalf("Custom sum returned wrong value, got %d, want %d", ret, test.sum) + } + } +} + func rot13(r rune) rune { switch { case r >= 'A' && r <= 'Z': diff --git a/sqlite3_trace.go b/sqlite3_trace.go index a75f52a..ece6035 100644 --- a/sqlite3_trace.go +++ b/sqlite3_trace.go @@ -14,16 +14,12 @@ package sqlite3 #endif #include -void stepTrampoline(sqlite3_context*, int, sqlite3_value**); -void doneTrampoline(sqlite3_context*); int traceCallbackTrampoline(unsigned int traceEventCode, void *ctx, void *p, void *x); */ import "C" import ( - "errors" "fmt" - "reflect" "strings" "sync" "unsafe" @@ -239,131 +235,6 @@ func popTraceMapping(connHandle uintptr) (TraceConfig, bool) { return entryCopy.config, found } -// RegisterAggregator makes a Go type available as a SQLite aggregation function. -// -// Because aggregation is incremental, it's implemented in Go with a -// type that has 2 methods: func Step(values) accumulates one row of -// data into the accumulator, and func Done() ret finalizes and -// returns the aggregate value. "values" and "ret" may be any type -// supported by RegisterFunc. -// -// RegisterAggregator takes as implementation a constructor function -// that constructs an instance of the aggregator type each time an -// aggregation begins. The constructor must return a pointer to a -// type, or an interface that implements Step() and Done(). -// -// The constructor function and the Step/Done methods may optionally -// return an error in addition to their other return values. -// -// See _example/go_custom_funcs for a detailed example. -func (c *SQLiteConn) RegisterAggregator(name string, impl interface{}, pure bool) error { - var ai aggInfo - ai.constructor = reflect.ValueOf(impl) - t := ai.constructor.Type() - if t.Kind() != reflect.Func { - return errors.New("non-function passed to RegisterAggregator") - } - if t.NumOut() != 1 && t.NumOut() != 2 { - return errors.New("SQLite aggregator constructors must return 1 or 2 values") - } - if t.NumOut() == 2 && !t.Out(1).Implements(reflect.TypeOf((*error)(nil)).Elem()) { - return errors.New("Second return value of SQLite function must be error") - } - if t.NumIn() != 0 { - return errors.New("SQLite aggregator constructors must not have arguments") - } - - agg := t.Out(0) - switch agg.Kind() { - case reflect.Ptr, reflect.Interface: - default: - return errors.New("SQlite aggregator constructor must return a pointer object") - } - stepFn, found := agg.MethodByName("Step") - if !found { - return errors.New("SQlite aggregator doesn't have a Step() function") - } - step := stepFn.Type - if step.NumOut() != 0 && step.NumOut() != 1 { - return errors.New("SQlite aggregator Step() function must return 0 or 1 values") - } - if step.NumOut() == 1 && !step.Out(0).Implements(reflect.TypeOf((*error)(nil)).Elem()) { - return errors.New("type of SQlite aggregator Step() return value must be error") - } - - stepNArgs := step.NumIn() - start := 0 - if agg.Kind() == reflect.Ptr { - // Skip over the method receiver - stepNArgs-- - start++ - } - if step.IsVariadic() { - stepNArgs-- - } - for i := start; i < start+stepNArgs; i++ { - conv, err := callbackArg(step.In(i)) - if err != nil { - return err - } - ai.stepArgConverters = append(ai.stepArgConverters, conv) - } - if step.IsVariadic() { - conv, err := callbackArg(t.In(start + stepNArgs).Elem()) - if err != nil { - return err - } - ai.stepVariadicConverter = conv - // Pass -1 to sqlite so that it allows any number of - // arguments. The call helper verifies that the minimum number - // of arguments is present for variadic functions. - stepNArgs = -1 - } - - doneFn, found := agg.MethodByName("Done") - if !found { - return errors.New("SQlite aggregator doesn't have a Done() function") - } - done := doneFn.Type - doneNArgs := done.NumIn() - if agg.Kind() == reflect.Ptr { - // Skip over the method receiver - doneNArgs-- - } - if doneNArgs != 0 { - return errors.New("SQlite aggregator Done() function must have no arguments") - } - if done.NumOut() != 1 && done.NumOut() != 2 { - return errors.New("SQLite aggregator Done() function must return 1 or 2 values") - } - if done.NumOut() == 2 && !done.Out(1).Implements(reflect.TypeOf((*error)(nil)).Elem()) { - return errors.New("second return value of SQLite aggregator Done() function must be error") - } - - conv, err := callbackRet(done.Out(0)) - if err != nil { - return err - } - ai.doneRetConverter = conv - ai.active = make(map[int64]reflect.Value) - ai.next = 1 - - // ai must outlast the database connection, or we'll have dangling pointers. - c.aggregators = append(c.aggregators, &ai) - - cname := C.CString(name) - defer C.free(unsafe.Pointer(cname)) - opts := C.SQLITE_UTF8 - if pure { - opts |= C.SQLITE_DETERMINISTIC - } - rv := sqlite3CreateFunction(c.db, cname, C.int(stepNArgs), C.int(opts), newHandle(c, &ai), nil, C.stepTrampoline, C.doneTrampoline) - if rv != C.SQLITE_OK { - return c.lastError() - } - return nil -} - // SetTrace installs or removes the trace callback for the given database connection. // It's not named 'RegisterTrace' because only one callback can be kept and called. // Calling SetTrace a second time on same database connection diff --git a/sqlite3_trace_test.go b/sqlite3_trace_test.go deleted file mode 100644 index 57a6757..0000000 --- a/sqlite3_trace_test.go +++ /dev/null @@ -1,72 +0,0 @@ -// Copyright (C) 2016 Yasuhiro Matsumoto . -// -// Use of this source code is governed by an MIT-style -// license that can be found in the LICENSE file. -// +build trace - -package sqlite3 - -import ( - "database/sql" - "testing" -) - -type sumAggregator int64 - -func (s *sumAggregator) Step(x int64) { - *s += sumAggregator(x) -} - -func (s *sumAggregator) Done() int64 { - return int64(*s) -} - -func TestAggregatorRegistration(t *testing.T) { - customSum := func() *sumAggregator { - var ret sumAggregator - return &ret - } - - sql.Register("sqlite3_AggregatorRegistration", &SQLiteDriver{ - ConnectHook: func(conn *SQLiteConn) error { - if err := conn.RegisterAggregator("customSum", customSum, true); err != nil { - return err - } - return nil - }, - }) - db, err := sql.Open("sqlite3_AggregatorRegistration", ":memory:") - if err != nil { - t.Fatal("Failed to open database:", err) - } - defer db.Close() - - _, err = db.Exec("create table foo (department integer, profits integer)") - if err != nil { - // trace feature is not implemented - t.Skip("Failed to create table:", err) - } - - _, err = db.Exec("insert into foo values (1, 10), (1, 20), (2, 42)") - if err != nil { - t.Fatal("Failed to insert records:", err) - } - - tests := []struct { - dept, sum int64 - }{ - {1, 30}, - {2, 42}, - } - - for _, test := range tests { - var ret int64 - err = db.QueryRow("select customSum(profits) from foo where department = $1 group by department", test.dept).Scan(&ret) - if err != nil { - t.Fatal("Query failed:", err) - } - if ret != test.sum { - t.Fatalf("Custom sum returned wrong value, got %d, want %d", ret, test.sum) - } - } -}