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-rw-r--r--vendor/golang.org/x/text/internal/catmsg/codec.go407
1 files changed, 407 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/internal/catmsg/codec.go b/vendor/golang.org/x/text/internal/catmsg/codec.go
new file mode 100644
index 0000000..49c9fc9
--- /dev/null
+++ b/vendor/golang.org/x/text/internal/catmsg/codec.go
@@ -0,0 +1,407 @@
+// Copyright 2017 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 catmsg
+
+import (
+ "errors"
+ "fmt"
+
+ "golang.org/x/text/language"
+)
+
+// A Renderer renders a Message.
+type Renderer interface {
+ // Render renders the given string. The given string may be interpreted as a
+ // format string, such as the one used by the fmt package or a template.
+ Render(s string)
+
+ // Arg returns the i-th argument passed to format a message. This method
+ // should return nil if there is no such argument. Messages need access to
+ // arguments to allow selecting a message based on linguistic features of
+ // those arguments.
+ Arg(i int) interface{}
+}
+
+// A Dictionary specifies a source of messages, including variables or macros.
+type Dictionary interface {
+ // Lookup returns the message for the given key. It returns false for ok if
+ // such a message could not be found.
+ Lookup(key string) (data string, ok bool)
+
+ // TODO: consider returning an interface, instead of a string. This will
+ // allow implementations to do their own message type decoding.
+}
+
+// An Encoder serializes a Message to a string.
+type Encoder struct {
+ // The root encoder is used for storing encoded variables.
+ root *Encoder
+ // The parent encoder provides the surrounding scopes for resolving variable
+ // names.
+ parent *Encoder
+
+ tag language.Tag
+
+ // buf holds the encoded message so far. After a message completes encoding,
+ // the contents of buf, prefixed by the encoded length, are flushed to the
+ // parent buffer.
+ buf []byte
+
+ // vars is the lookup table of variables in the current scope.
+ vars []keyVal
+
+ err error
+ inBody bool // if false next call must be EncodeMessageType
+}
+
+type keyVal struct {
+ key string
+ offset int
+}
+
+// Language reports the language for which the encoded message will be stored
+// in the Catalog.
+func (e *Encoder) Language() language.Tag { return e.tag }
+
+func (e *Encoder) setError(err error) {
+ if e.root.err == nil {
+ e.root.err = err
+ }
+}
+
+// EncodeUint encodes x.
+func (e *Encoder) EncodeUint(x uint64) {
+ e.checkInBody()
+ var buf [maxVarintBytes]byte
+ n := encodeUint(buf[:], x)
+ e.buf = append(e.buf, buf[:n]...)
+}
+
+// EncodeString encodes s.
+func (e *Encoder) EncodeString(s string) {
+ e.checkInBody()
+ e.EncodeUint(uint64(len(s)))
+ e.buf = append(e.buf, s...)
+}
+
+// EncodeMessageType marks the current message to be of type h.
+//
+// It must be the first call of a Message's Compile method.
+func (e *Encoder) EncodeMessageType(h Handle) {
+ if e.inBody {
+ panic("catmsg: EncodeMessageType not the first method called")
+ }
+ e.inBody = true
+ e.EncodeUint(uint64(h))
+}
+
+// EncodeMessage serializes the given message inline at the current position.
+func (e *Encoder) EncodeMessage(m Message) error {
+ e = &Encoder{root: e.root, parent: e, tag: e.tag}
+ err := m.Compile(e)
+ if _, ok := m.(*Var); !ok {
+ e.flushTo(e.parent)
+ }
+ return err
+}
+
+func (e *Encoder) checkInBody() {
+ if !e.inBody {
+ panic("catmsg: expected prior call to EncodeMessageType")
+ }
+}
+
+// stripPrefix indicates the number of prefix bytes that must be stripped to
+// turn a single-element sequence into a message that is just this single member
+// without its size prefix. If the message can be stripped, b[1:n] contains the
+// size prefix.
+func stripPrefix(b []byte) (n int) {
+ if len(b) > 0 && Handle(b[0]) == msgFirst {
+ x, n, _ := decodeUint(b[1:])
+ if 1+n+int(x) == len(b) {
+ return 1 + n
+ }
+ }
+ return 0
+}
+
+func (e *Encoder) flushTo(dst *Encoder) {
+ data := e.buf
+ p := stripPrefix(data)
+ if p > 0 {
+ data = data[1:]
+ } else {
+ // Prefix the size.
+ dst.EncodeUint(uint64(len(data)))
+ }
+ dst.buf = append(dst.buf, data...)
+}
+
+func (e *Encoder) addVar(key string, m Message) error {
+ for _, v := range e.parent.vars {
+ if v.key == key {
+ err := fmt.Errorf("catmsg: duplicate variable %q", key)
+ e.setError(err)
+ return err
+ }
+ }
+ scope := e.parent
+ // If a variable message is Incomplete, and does not evaluate to a message
+ // during execution, we fall back to the variable name. We encode this by
+ // appending the variable name if the message reports it's incomplete.
+
+ err := m.Compile(e)
+ if err != ErrIncomplete {
+ e.setError(err)
+ }
+ switch {
+ case len(e.buf) == 1 && Handle(e.buf[0]) == msgFirst: // empty sequence
+ e.buf = e.buf[:0]
+ e.inBody = false
+ fallthrough
+ case len(e.buf) == 0:
+ // Empty message.
+ if err := String(key).Compile(e); err != nil {
+ e.setError(err)
+ }
+ case err == ErrIncomplete:
+ if Handle(e.buf[0]) != msgFirst {
+ seq := &Encoder{root: e.root, parent: e}
+ seq.EncodeMessageType(msgFirst)
+ e.flushTo(seq)
+ e = seq
+ }
+ // e contains a sequence; append the fallback string.
+ e.EncodeMessage(String(key))
+ }
+
+ // Flush result to variable heap.
+ offset := len(e.root.buf)
+ e.flushTo(e.root)
+ e.buf = e.buf[:0]
+
+ // Record variable offset in current scope.
+ scope.vars = append(scope.vars, keyVal{key: key, offset: offset})
+ return err
+}
+
+const (
+ substituteVar = iota
+ substituteMacro
+ substituteError
+)
+
+// EncodeSubstitution inserts a resolved reference to a variable or macro.
+//
+// This call must be matched with a call to ExecuteSubstitution at decoding
+// time.
+func (e *Encoder) EncodeSubstitution(name string, arguments ...int) {
+ if arity := len(arguments); arity > 0 {
+ // TODO: also resolve macros.
+ e.EncodeUint(substituteMacro)
+ e.EncodeString(name)
+ for _, a := range arguments {
+ e.EncodeUint(uint64(a))
+ }
+ return
+ }
+ for scope := e; scope != nil; scope = scope.parent {
+ for _, v := range scope.vars {
+ if v.key != name {
+ continue
+ }
+ e.EncodeUint(substituteVar) // TODO: support arity > 0
+ e.EncodeUint(uint64(v.offset))
+ return
+ }
+ }
+ // TODO: refer to dictionary-wide scoped variables.
+ e.EncodeUint(substituteError)
+ e.EncodeString(name)
+ e.setError(fmt.Errorf("catmsg: unknown var %q", name))
+}
+
+// A Decoder deserializes and evaluates messages that are encoded by an encoder.
+type Decoder struct {
+ tag language.Tag
+ dst Renderer
+ macros Dictionary
+
+ err error
+ vars string
+ data string
+
+ macroArg int // TODO: allow more than one argument
+}
+
+// NewDecoder returns a new Decoder.
+//
+// Decoders are designed to be reused for multiple invocations of Execute.
+// Only one goroutine may call Execute concurrently.
+func NewDecoder(tag language.Tag, r Renderer, macros Dictionary) *Decoder {
+ return &Decoder{
+ tag: tag,
+ dst: r,
+ macros: macros,
+ }
+}
+
+func (d *Decoder) setError(err error) {
+ if d.err == nil {
+ d.err = err
+ }
+}
+
+// Language returns the language in which the message is being rendered.
+//
+// The destination language may be a child language of the language used for
+// encoding. For instance, a decoding language of "pt-PT"" is consistent with an
+// encoding language of "pt".
+func (d *Decoder) Language() language.Tag { return d.tag }
+
+// Done reports whether there are more bytes to process in this message.
+func (d *Decoder) Done() bool { return len(d.data) == 0 }
+
+// Render implements Renderer.
+func (d *Decoder) Render(s string) { d.dst.Render(s) }
+
+// Arg implements Renderer.
+//
+// During evaluation of macros, the argument positions may be mapped to
+// arguments that differ from the original call.
+func (d *Decoder) Arg(i int) interface{} {
+ if d.macroArg != 0 {
+ if i != 1 {
+ panic("catmsg: only macros with single argument supported")
+ }
+ i = d.macroArg
+ }
+ return d.dst.Arg(i)
+}
+
+// DecodeUint decodes a number that was encoded with EncodeUint and advances the
+// position.
+func (d *Decoder) DecodeUint() uint64 {
+ x, n, err := decodeUintString(d.data)
+ d.data = d.data[n:]
+ if err != nil {
+ d.setError(err)
+ }
+ return x
+}
+
+// DecodeString decodes a string that was encoded with EncodeString and advances
+// the position.
+func (d *Decoder) DecodeString() string {
+ size := d.DecodeUint()
+ s := d.data[:size]
+ d.data = d.data[size:]
+ return s
+}
+
+// SkipMessage skips the message at the current location and advances the
+// position.
+func (d *Decoder) SkipMessage() {
+ n := int(d.DecodeUint())
+ d.data = d.data[n:]
+}
+
+// Execute decodes and evaluates msg.
+//
+// Only one goroutine may call execute.
+func (d *Decoder) Execute(msg string) error {
+ d.err = nil
+ if !d.execute(msg) {
+ return ErrNoMatch
+ }
+ return d.err
+}
+
+func (d *Decoder) execute(msg string) bool {
+ saved := d.data
+ d.data = msg
+ ok := d.executeMessage()
+ d.data = saved
+ return ok
+}
+
+// executeMessageFromData is like execute, but also decodes a leading message
+// size and clips the given string accordingly.
+//
+// It reports the number of bytes consumed and whether a message was selected.
+func (d *Decoder) executeMessageFromData(s string) (n int, ok bool) {
+ saved := d.data
+ d.data = s
+ size := int(d.DecodeUint())
+ n = len(s) - len(d.data)
+ // Sanitize the setting. This allows skipping a size argument for
+ // RawString and method Done.
+ d.data = d.data[:size]
+ ok = d.executeMessage()
+ n += size - len(d.data)
+ d.data = saved
+ return n, ok
+}
+
+var errUnknownHandler = errors.New("catmsg: string contains unsupported handler")
+
+// executeMessage reads the handle id, initializes the decoder and executes the
+// message. It is assumed that all of d.data[d.p:] is the single message.
+func (d *Decoder) executeMessage() bool {
+ if d.Done() {
+ // We interpret no data as a valid empty message.
+ return true
+ }
+ handle := d.DecodeUint()
+
+ var fn Handler
+ mutex.Lock()
+ if int(handle) < len(handlers) {
+ fn = handlers[handle]
+ }
+ mutex.Unlock()
+ if fn == nil {
+ d.setError(errUnknownHandler)
+ d.execute(fmt.Sprintf("\x02$!(UNKNOWNMSGHANDLER=%#x)", handle))
+ return true
+ }
+ return fn(d)
+}
+
+// ExecuteMessage decodes and executes the message at the current position.
+func (d *Decoder) ExecuteMessage() bool {
+ n, ok := d.executeMessageFromData(d.data)
+ d.data = d.data[n:]
+ return ok
+}
+
+// ExecuteSubstitution executes the message corresponding to the substitution
+// as encoded by EncodeSubstitution.
+func (d *Decoder) ExecuteSubstitution() {
+ switch x := d.DecodeUint(); x {
+ case substituteVar:
+ offset := d.DecodeUint()
+ d.executeMessageFromData(d.vars[offset:])
+ case substituteMacro:
+ name := d.DecodeString()
+ data, ok := d.macros.Lookup(name)
+ old := d.macroArg
+ // TODO: support macros of arity other than 1.
+ d.macroArg = int(d.DecodeUint())
+ switch {
+ case !ok:
+ // TODO: detect this at creation time.
+ d.setError(fmt.Errorf("catmsg: undefined macro %q", name))
+ fallthrough
+ case !d.execute(data):
+ d.dst.Render(name) // fall back to macro name.
+ }
+ d.macroArg = old
+ case substituteError:
+ d.dst.Render(d.DecodeString())
+ default:
+ panic("catmsg: unreachable")
+ }
+}