From 73df946d56c74384511a194dd01dbe099584fd1a Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 28 Apr 2024 15:14:23 +0200 Subject: Adding upstream version 1.16.10. Signed-off-by: Daniel Baumann --- src/text/template/funcs.go | 766 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 766 insertions(+) create mode 100644 src/text/template/funcs.go (limited to 'src/text/template/funcs.go') diff --git a/src/text/template/funcs.go b/src/text/template/funcs.go new file mode 100644 index 0000000..1b6940a --- /dev/null +++ b/src/text/template/funcs.go @@ -0,0 +1,766 @@ +// Copyright 2011 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. + +package template + +import ( + "bytes" + "errors" + "fmt" + "io" + "net/url" + "reflect" + "strings" + "sync" + "unicode" + "unicode/utf8" +) + +// FuncMap is the type of the map defining the mapping from names to functions. +// Each function must have either a single return value, or two return values of +// which the second has type error. In that case, if the second (error) +// return value evaluates to non-nil during execution, execution terminates and +// Execute returns that error. +// +// When template execution invokes a function with an argument list, that list +// must be assignable to the function's parameter types. Functions meant to +// apply to arguments of arbitrary type can use parameters of type interface{} or +// of type reflect.Value. Similarly, functions meant to return a result of arbitrary +// type can return interface{} or reflect.Value. +type FuncMap map[string]interface{} + +// builtins returns the FuncMap. +// It is not a global variable so the linker can dead code eliminate +// more when this isn't called. See golang.org/issue/36021. +// TODO: revert this back to a global map once golang.org/issue/2559 is fixed. +func builtins() FuncMap { + return FuncMap{ + "and": and, + "call": call, + "html": HTMLEscaper, + "index": index, + "slice": slice, + "js": JSEscaper, + "len": length, + "not": not, + "or": or, + "print": fmt.Sprint, + "printf": fmt.Sprintf, + "println": fmt.Sprintln, + "urlquery": URLQueryEscaper, + + // Comparisons + "eq": eq, // == + "ge": ge, // >= + "gt": gt, // > + "le": le, // <= + "lt": lt, // < + "ne": ne, // != + } +} + +var builtinFuncsOnce struct { + sync.Once + v map[string]reflect.Value +} + +// builtinFuncsOnce lazily computes & caches the builtinFuncs map. +// TODO: revert this back to a global map once golang.org/issue/2559 is fixed. +func builtinFuncs() map[string]reflect.Value { + builtinFuncsOnce.Do(func() { + builtinFuncsOnce.v = createValueFuncs(builtins()) + }) + return builtinFuncsOnce.v +} + +// createValueFuncs turns a FuncMap into a map[string]reflect.Value +func createValueFuncs(funcMap FuncMap) map[string]reflect.Value { + m := make(map[string]reflect.Value) + addValueFuncs(m, funcMap) + return m +} + +// addValueFuncs adds to values the functions in funcs, converting them to reflect.Values. +func addValueFuncs(out map[string]reflect.Value, in FuncMap) { + for name, fn := range in { + if !goodName(name) { + panic(fmt.Errorf("function name %q is not a valid identifier", name)) + } + v := reflect.ValueOf(fn) + if v.Kind() != reflect.Func { + panic("value for " + name + " not a function") + } + if !goodFunc(v.Type()) { + panic(fmt.Errorf("can't install method/function %q with %d results", name, v.Type().NumOut())) + } + out[name] = v + } +} + +// addFuncs adds to values the functions in funcs. It does no checking of the input - +// call addValueFuncs first. +func addFuncs(out, in FuncMap) { + for name, fn := range in { + out[name] = fn + } +} + +// goodFunc reports whether the function or method has the right result signature. +func goodFunc(typ reflect.Type) bool { + // We allow functions with 1 result or 2 results where the second is an error. + switch { + case typ.NumOut() == 1: + return true + case typ.NumOut() == 2 && typ.Out(1) == errorType: + return true + } + return false +} + +// goodName reports whether the function name is a valid identifier. +func goodName(name string) bool { + if name == "" { + return false + } + for i, r := range name { + switch { + case r == '_': + case i == 0 && !unicode.IsLetter(r): + return false + case !unicode.IsLetter(r) && !unicode.IsDigit(r): + return false + } + } + return true +} + +// findFunction looks for a function in the template, and global map. +func findFunction(name string, tmpl *Template) (reflect.Value, bool) { + if tmpl != nil && tmpl.common != nil { + tmpl.muFuncs.RLock() + defer tmpl.muFuncs.RUnlock() + if fn := tmpl.execFuncs[name]; fn.IsValid() { + return fn, true + } + } + if fn := builtinFuncs()[name]; fn.IsValid() { + return fn, true + } + return reflect.Value{}, false +} + +// prepareArg checks if value can be used as an argument of type argType, and +// converts an invalid value to appropriate zero if possible. +func prepareArg(value reflect.Value, argType reflect.Type) (reflect.Value, error) { + if !value.IsValid() { + if !canBeNil(argType) { + return reflect.Value{}, fmt.Errorf("value is nil; should be of type %s", argType) + } + value = reflect.Zero(argType) + } + if value.Type().AssignableTo(argType) { + return value, nil + } + if intLike(value.Kind()) && intLike(argType.Kind()) && value.Type().ConvertibleTo(argType) { + value = value.Convert(argType) + return value, nil + } + return reflect.Value{}, fmt.Errorf("value has type %s; should be %s", value.Type(), argType) +} + +func intLike(typ reflect.Kind) bool { + switch typ { + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + return true + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + return true + } + return false +} + +// indexArg checks if a reflect.Value can be used as an index, and converts it to int if possible. +func indexArg(index reflect.Value, cap int) (int, error) { + var x int64 + switch index.Kind() { + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + x = index.Int() + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + x = int64(index.Uint()) + case reflect.Invalid: + return 0, fmt.Errorf("cannot index slice/array with nil") + default: + return 0, fmt.Errorf("cannot index slice/array with type %s", index.Type()) + } + if x < 0 || int(x) < 0 || int(x) > cap { + return 0, fmt.Errorf("index out of range: %d", x) + } + return int(x), nil +} + +// Indexing. + +// index returns the result of indexing its first argument by the following +// arguments. Thus "index x 1 2 3" is, in Go syntax, x[1][2][3]. Each +// indexed item must be a map, slice, or array. +func index(item reflect.Value, indexes ...reflect.Value) (reflect.Value, error) { + item = indirectInterface(item) + if !item.IsValid() { + return reflect.Value{}, fmt.Errorf("index of untyped nil") + } + for _, index := range indexes { + index = indirectInterface(index) + var isNil bool + if item, isNil = indirect(item); isNil { + return reflect.Value{}, fmt.Errorf("index of nil pointer") + } + switch item.Kind() { + case reflect.Array, reflect.Slice, reflect.String: + x, err := indexArg(index, item.Len()) + if err != nil { + return reflect.Value{}, err + } + item = item.Index(x) + case reflect.Map: + index, err := prepareArg(index, item.Type().Key()) + if err != nil { + return reflect.Value{}, err + } + if x := item.MapIndex(index); x.IsValid() { + item = x + } else { + item = reflect.Zero(item.Type().Elem()) + } + case reflect.Invalid: + // the loop holds invariant: item.IsValid() + panic("unreachable") + default: + return reflect.Value{}, fmt.Errorf("can't index item of type %s", item.Type()) + } + } + return item, nil +} + +// Slicing. + +// slice returns the result of slicing its first argument by the remaining +// arguments. Thus "slice x 1 2" is, in Go syntax, x[1:2], while "slice x" +// is x[:], "slice x 1" is x[1:], and "slice x 1 2 3" is x[1:2:3]. The first +// argument must be a string, slice, or array. +func slice(item reflect.Value, indexes ...reflect.Value) (reflect.Value, error) { + item = indirectInterface(item) + if !item.IsValid() { + return reflect.Value{}, fmt.Errorf("slice of untyped nil") + } + if len(indexes) > 3 { + return reflect.Value{}, fmt.Errorf("too many slice indexes: %d", len(indexes)) + } + var cap int + switch item.Kind() { + case reflect.String: + if len(indexes) == 3 { + return reflect.Value{}, fmt.Errorf("cannot 3-index slice a string") + } + cap = item.Len() + case reflect.Array, reflect.Slice: + cap = item.Cap() + default: + return reflect.Value{}, fmt.Errorf("can't slice item of type %s", item.Type()) + } + // set default values for cases item[:], item[i:]. + idx := [3]int{0, item.Len()} + for i, index := range indexes { + x, err := indexArg(index, cap) + if err != nil { + return reflect.Value{}, err + } + idx[i] = x + } + // given item[i:j], make sure i <= j. + if idx[0] > idx[1] { + return reflect.Value{}, fmt.Errorf("invalid slice index: %d > %d", idx[0], idx[1]) + } + if len(indexes) < 3 { + return item.Slice(idx[0], idx[1]), nil + } + // given item[i:j:k], make sure i <= j <= k. + if idx[1] > idx[2] { + return reflect.Value{}, fmt.Errorf("invalid slice index: %d > %d", idx[1], idx[2]) + } + return item.Slice3(idx[0], idx[1], idx[2]), nil +} + +// Length + +// length returns the length of the item, with an error if it has no defined length. +func length(item reflect.Value) (int, error) { + item, isNil := indirect(item) + if isNil { + return 0, fmt.Errorf("len of nil pointer") + } + switch item.Kind() { + case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice, reflect.String: + return item.Len(), nil + } + return 0, fmt.Errorf("len of type %s", item.Type()) +} + +// Function invocation + +// call returns the result of evaluating the first argument as a function. +// The function must return 1 result, or 2 results, the second of which is an error. +func call(fn reflect.Value, args ...reflect.Value) (reflect.Value, error) { + fn = indirectInterface(fn) + if !fn.IsValid() { + return reflect.Value{}, fmt.Errorf("call of nil") + } + typ := fn.Type() + if typ.Kind() != reflect.Func { + return reflect.Value{}, fmt.Errorf("non-function of type %s", typ) + } + if !goodFunc(typ) { + return reflect.Value{}, fmt.Errorf("function called with %d args; should be 1 or 2", typ.NumOut()) + } + numIn := typ.NumIn() + var dddType reflect.Type + if typ.IsVariadic() { + if len(args) < numIn-1 { + return reflect.Value{}, fmt.Errorf("wrong number of args: got %d want at least %d", len(args), numIn-1) + } + dddType = typ.In(numIn - 1).Elem() + } else { + if len(args) != numIn { + return reflect.Value{}, fmt.Errorf("wrong number of args: got %d want %d", len(args), numIn) + } + } + argv := make([]reflect.Value, len(args)) + for i, arg := range args { + arg = indirectInterface(arg) + // Compute the expected type. Clumsy because of variadics. + argType := dddType + if !typ.IsVariadic() || i < numIn-1 { + argType = typ.In(i) + } + + var err error + if argv[i], err = prepareArg(arg, argType); err != nil { + return reflect.Value{}, fmt.Errorf("arg %d: %s", i, err) + } + } + return safeCall(fn, argv) +} + +// safeCall runs fun.Call(args), and returns the resulting value and error, if +// any. If the call panics, the panic value is returned as an error. +func safeCall(fun reflect.Value, args []reflect.Value) (val reflect.Value, err error) { + defer func() { + if r := recover(); r != nil { + if e, ok := r.(error); ok { + err = e + } else { + err = fmt.Errorf("%v", r) + } + } + }() + ret := fun.Call(args) + if len(ret) == 2 && !ret[1].IsNil() { + return ret[0], ret[1].Interface().(error) + } + return ret[0], nil +} + +// Boolean logic. + +func truth(arg reflect.Value) bool { + t, _ := isTrue(indirectInterface(arg)) + return t +} + +// and computes the Boolean AND of its arguments, returning +// the first false argument it encounters, or the last argument. +func and(arg0 reflect.Value, args ...reflect.Value) reflect.Value { + if !truth(arg0) { + return arg0 + } + for i := range args { + arg0 = args[i] + if !truth(arg0) { + break + } + } + return arg0 +} + +// or computes the Boolean OR of its arguments, returning +// the first true argument it encounters, or the last argument. +func or(arg0 reflect.Value, args ...reflect.Value) reflect.Value { + if truth(arg0) { + return arg0 + } + for i := range args { + arg0 = args[i] + if truth(arg0) { + break + } + } + return arg0 +} + +// not returns the Boolean negation of its argument. +func not(arg reflect.Value) bool { + return !truth(arg) +} + +// Comparison. + +// TODO: Perhaps allow comparison between signed and unsigned integers. + +var ( + errBadComparisonType = errors.New("invalid type for comparison") + errBadComparison = errors.New("incompatible types for comparison") + errNoComparison = errors.New("missing argument for comparison") +) + +type kind int + +const ( + invalidKind kind = iota + boolKind + complexKind + intKind + floatKind + stringKind + uintKind +) + +func basicKind(v reflect.Value) (kind, error) { + switch v.Kind() { + case reflect.Bool: + return boolKind, nil + case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: + return intKind, nil + case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: + return uintKind, nil + case reflect.Float32, reflect.Float64: + return floatKind, nil + case reflect.Complex64, reflect.Complex128: + return complexKind, nil + case reflect.String: + return stringKind, nil + } + return invalidKind, errBadComparisonType +} + +// eq evaluates the comparison a == b || a == c || ... +func eq(arg1 reflect.Value, arg2 ...reflect.Value) (bool, error) { + arg1 = indirectInterface(arg1) + if arg1 != zero { + if t1 := arg1.Type(); !t1.Comparable() { + return false, fmt.Errorf("uncomparable type %s: %v", t1, arg1) + } + } + if len(arg2) == 0 { + return false, errNoComparison + } + k1, _ := basicKind(arg1) + for _, arg := range arg2 { + arg = indirectInterface(arg) + k2, _ := basicKind(arg) + truth := false + if k1 != k2 { + // Special case: Can compare integer values regardless of type's sign. + switch { + case k1 == intKind && k2 == uintKind: + truth = arg1.Int() >= 0 && uint64(arg1.Int()) == arg.Uint() + case k1 == uintKind && k2 == intKind: + truth = arg.Int() >= 0 && arg1.Uint() == uint64(arg.Int()) + default: + return false, errBadComparison + } + } else { + switch k1 { + case boolKind: + truth = arg1.Bool() == arg.Bool() + case complexKind: + truth = arg1.Complex() == arg.Complex() + case floatKind: + truth = arg1.Float() == arg.Float() + case intKind: + truth = arg1.Int() == arg.Int() + case stringKind: + truth = arg1.String() == arg.String() + case uintKind: + truth = arg1.Uint() == arg.Uint() + default: + if arg == zero { + truth = arg1 == arg + } else { + if t2 := arg.Type(); !t2.Comparable() { + return false, fmt.Errorf("uncomparable type %s: %v", t2, arg) + } + truth = arg1.Interface() == arg.Interface() + } + } + } + if truth { + return true, nil + } + } + return false, nil +} + +// ne evaluates the comparison a != b. +func ne(arg1, arg2 reflect.Value) (bool, error) { + // != is the inverse of ==. + equal, err := eq(arg1, arg2) + return !equal, err +} + +// lt evaluates the comparison a < b. +func lt(arg1, arg2 reflect.Value) (bool, error) { + arg1 = indirectInterface(arg1) + k1, err := basicKind(arg1) + if err != nil { + return false, err + } + arg2 = indirectInterface(arg2) + k2, err := basicKind(arg2) + if err != nil { + return false, err + } + truth := false + if k1 != k2 { + // Special case: Can compare integer values regardless of type's sign. + switch { + case k1 == intKind && k2 == uintKind: + truth = arg1.Int() < 0 || uint64(arg1.Int()) < arg2.Uint() + case k1 == uintKind && k2 == intKind: + truth = arg2.Int() >= 0 && arg1.Uint() < uint64(arg2.Int()) + default: + return false, errBadComparison + } + } else { + switch k1 { + case boolKind, complexKind: + return false, errBadComparisonType + case floatKind: + truth = arg1.Float() < arg2.Float() + case intKind: + truth = arg1.Int() < arg2.Int() + case stringKind: + truth = arg1.String() < arg2.String() + case uintKind: + truth = arg1.Uint() < arg2.Uint() + default: + panic("invalid kind") + } + } + return truth, nil +} + +// le evaluates the comparison <= b. +func le(arg1, arg2 reflect.Value) (bool, error) { + // <= is < or ==. + lessThan, err := lt(arg1, arg2) + if lessThan || err != nil { + return lessThan, err + } + return eq(arg1, arg2) +} + +// gt evaluates the comparison a > b. +func gt(arg1, arg2 reflect.Value) (bool, error) { + // > is the inverse of <=. + lessOrEqual, err := le(arg1, arg2) + if err != nil { + return false, err + } + return !lessOrEqual, nil +} + +// ge evaluates the comparison a >= b. +func ge(arg1, arg2 reflect.Value) (bool, error) { + // >= is the inverse of <. + lessThan, err := lt(arg1, arg2) + if err != nil { + return false, err + } + return !lessThan, nil +} + +// HTML escaping. + +var ( + htmlQuot = []byte(""") // shorter than """ + htmlApos = []byte("'") // shorter than "'" and apos was not in HTML until HTML5 + htmlAmp = []byte("&") + htmlLt = []byte("<") + htmlGt = []byte(">") + htmlNull = []byte("\uFFFD") +) + +// HTMLEscape writes to w the escaped HTML equivalent of the plain text data b. +func HTMLEscape(w io.Writer, b []byte) { + last := 0 + for i, c := range b { + var html []byte + switch c { + case '\000': + html = htmlNull + case '"': + html = htmlQuot + case '\'': + html = htmlApos + case '&': + html = htmlAmp + case '<': + html = htmlLt + case '>': + html = htmlGt + default: + continue + } + w.Write(b[last:i]) + w.Write(html) + last = i + 1 + } + w.Write(b[last:]) +} + +// HTMLEscapeString returns the escaped HTML equivalent of the plain text data s. +func HTMLEscapeString(s string) string { + // Avoid allocation if we can. + if !strings.ContainsAny(s, "'\"&<>\000") { + return s + } + var b bytes.Buffer + HTMLEscape(&b, []byte(s)) + return b.String() +} + +// HTMLEscaper returns the escaped HTML equivalent of the textual +// representation of its arguments. +func HTMLEscaper(args ...interface{}) string { + return HTMLEscapeString(evalArgs(args)) +} + +// JavaScript escaping. + +var ( + jsLowUni = []byte(`\u00`) + hex = []byte("0123456789ABCDEF") + + jsBackslash = []byte(`\\`) + jsApos = []byte(`\'`) + jsQuot = []byte(`\"`) + jsLt = []byte(`\u003C`) + jsGt = []byte(`\u003E`) + jsAmp = []byte(`\u0026`) + jsEq = []byte(`\u003D`) +) + +// JSEscape writes to w the escaped JavaScript equivalent of the plain text data b. +func JSEscape(w io.Writer, b []byte) { + last := 0 + for i := 0; i < len(b); i++ { + c := b[i] + + if !jsIsSpecial(rune(c)) { + // fast path: nothing to do + continue + } + w.Write(b[last:i]) + + if c < utf8.RuneSelf { + // Quotes, slashes and angle brackets get quoted. + // Control characters get written as \u00XX. + switch c { + case '\\': + w.Write(jsBackslash) + case '\'': + w.Write(jsApos) + case '"': + w.Write(jsQuot) + case '<': + w.Write(jsLt) + case '>': + w.Write(jsGt) + case '&': + w.Write(jsAmp) + case '=': + w.Write(jsEq) + default: + w.Write(jsLowUni) + t, b := c>>4, c&0x0f + w.Write(hex[t : t+1]) + w.Write(hex[b : b+1]) + } + } else { + // Unicode rune. + r, size := utf8.DecodeRune(b[i:]) + if unicode.IsPrint(r) { + w.Write(b[i : i+size]) + } else { + fmt.Fprintf(w, "\\u%04X", r) + } + i += size - 1 + } + last = i + 1 + } + w.Write(b[last:]) +} + +// JSEscapeString returns the escaped JavaScript equivalent of the plain text data s. +func JSEscapeString(s string) string { + // Avoid allocation if we can. + if strings.IndexFunc(s, jsIsSpecial) < 0 { + return s + } + var b bytes.Buffer + JSEscape(&b, []byte(s)) + return b.String() +} + +func jsIsSpecial(r rune) bool { + switch r { + case '\\', '\'', '"', '<', '>', '&', '=': + return true + } + return r < ' ' || utf8.RuneSelf <= r +} + +// JSEscaper returns the escaped JavaScript equivalent of the textual +// representation of its arguments. +func JSEscaper(args ...interface{}) string { + return JSEscapeString(evalArgs(args)) +} + +// URLQueryEscaper returns the escaped value of the textual representation of +// its arguments in a form suitable for embedding in a URL query. +func URLQueryEscaper(args ...interface{}) string { + return url.QueryEscape(evalArgs(args)) +} + +// evalArgs formats the list of arguments into a string. It is therefore equivalent to +// fmt.Sprint(args...) +// except that each argument is indirected (if a pointer), as required, +// using the same rules as the default string evaluation during template +// execution. +func evalArgs(args []interface{}) string { + ok := false + var s string + // Fast path for simple common case. + if len(args) == 1 { + s, ok = args[0].(string) + } + if !ok { + for i, arg := range args { + a, ok := printableValue(reflect.ValueOf(arg)) + if ok { + args[i] = a + } // else let fmt do its thing + } + s = fmt.Sprint(args...) + } + return s +} -- cgit v1.2.3