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// Copyright 2019 The Go Authors. All rights reserved. |
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// Use of this source code is governed by a BSD-style |
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// license that can be found in the LICENSE file. |
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package impl |
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import ( |
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"encoding/binary" |
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"encoding/json" |
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"hash/crc32" |
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"math" |
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"reflect" |
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"google.golang.org/protobuf/internal/errors" |
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"google.golang.org/protobuf/reflect/protoreflect" |
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"google.golang.org/protobuf/runtime/protoiface" |
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) |
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// These functions exist to support exported APIs in generated protobufs. |
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// While these are deprecated, they cannot be removed for compatibility reasons. |
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// LegacyEnumName returns the name of enums used in legacy code. |
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func (Export) LegacyEnumName(ed protoreflect.EnumDescriptor) string { |
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return legacyEnumName(ed) |
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} |
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// LegacyMessageTypeOf returns the protoreflect.MessageType for m, |
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// with name used as the message name if necessary. |
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func (Export) LegacyMessageTypeOf(m protoiface.MessageV1, name protoreflect.FullName) protoreflect.MessageType { |
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if mv := (Export{}).protoMessageV2Of(m); mv != nil { |
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return mv.ProtoReflect().Type() |
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} |
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return legacyLoadMessageType(reflect.TypeOf(m), name) |
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} |
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// UnmarshalJSONEnum unmarshals an enum from a JSON-encoded input. |
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// The input can either be a string representing the enum value by name, |
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// or a number representing the enum number itself. |
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func (Export) UnmarshalJSONEnum(ed protoreflect.EnumDescriptor, b []byte) (protoreflect.EnumNumber, error) { |
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if b[0] == '"' { |
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var name protoreflect.Name |
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if err := json.Unmarshal(b, &name); err != nil { |
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return 0, errors.New("invalid input for enum %v: %s", ed.FullName(), b) |
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} |
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ev := ed.Values().ByName(name) |
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if ev == nil { |
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return 0, errors.New("invalid value for enum %v: %s", ed.FullName(), name) |
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} |
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return ev.Number(), nil |
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} else { |
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var num protoreflect.EnumNumber |
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if err := json.Unmarshal(b, &num); err != nil { |
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return 0, errors.New("invalid input for enum %v: %s", ed.FullName(), b) |
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} |
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return num, nil |
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} |
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} |
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// CompressGZIP compresses the input as a GZIP-encoded file. |
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// The current implementation does no compression. |
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func (Export) CompressGZIP(in []byte) (out []byte) { |
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// RFC 1952, section 2.3.1. |
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var gzipHeader = [10]byte{0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xff} |
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// RFC 1951, section 3.2.4. |
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var blockHeader [5]byte |
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const maxBlockSize = math.MaxUint16 |
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numBlocks := 1 + len(in)/maxBlockSize |
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// RFC 1952, section 2.3.1. |
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var gzipFooter [8]byte |
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binary.LittleEndian.PutUint32(gzipFooter[0:4], crc32.ChecksumIEEE(in)) |
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binary.LittleEndian.PutUint32(gzipFooter[4:8], uint32(len(in))) |
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// Encode the input without compression using raw DEFLATE blocks. |
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out = make([]byte, 0, len(gzipHeader)+len(blockHeader)*numBlocks+len(in)+len(gzipFooter)) |
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out = append(out, gzipHeader[:]...) |
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for blockHeader[0] == 0 { |
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blockSize := maxBlockSize |
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if blockSize > len(in) { |
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blockHeader[0] = 0x01 // final bit per RFC 1951, section 3.2.3. |
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blockSize = len(in) |
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} |
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binary.LittleEndian.PutUint16(blockHeader[1:3], uint16(blockSize)) |
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binary.LittleEndian.PutUint16(blockHeader[3:5], ^uint16(blockSize)) |
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out = append(out, blockHeader[:]...) |
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out = append(out, in[:blockSize]...) |
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in = in[blockSize:] |
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} |
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out = append(out, gzipFooter[:]...) |
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return out |
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} |