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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
package com.google.protobuf;
/**
* RawMessageInfo stores the same amount of information as {@link MessageInfo} but in a more compact
* format.
*/
@CheckReturnValue
final class RawMessageInfo implements MessageInfo {
private static final int IS_PROTO2_BIT = 0x1;
private static final int IS_EDITION_BIT = 0x4;
private final MessageLite defaultInstance;
/**
* The compact format packs everything in a String object and a Object[] array. The String object
* is encoded with field number, field type, hasbits offset, oneof index, etc., whereas the
* Object[] array contains field references, class references, instance references, etc.
*
* The String object encodes a sequence of integers into UTF-16 characters. For each int, it
* will be encoding into 1 to 3 UTF-16 characters depending on its unsigned value:
*
*
* - 1 char: [c1: 0x0000 - 0xD7FF] = int of the same value.
*
- 2 chars: [c1: 0xE000 - 0xFFFF], [c2: 0x0000 - 0xD7FF] = (c2 << 13) | (c1 & 0x1FFF)
*
- 3 chars: [c1: 0xE000 - 0xFFFF], [c2: 0xE000 - 0xFFFF], [c3: 0x0000 - 0xD7FF] = (c3 << 26)
* | ((c2 & 0x1FFF) << 13) | (c1 & 0x1FFF)
*
*
* Note that we don't use UTF-16 surrogate pairs [0xD800 - 0xDFFF] because they have to come in
* pairs to form a valid UTF-16char sequence and don't help us encode values more efficiently.
*
*
The integer sequence encoded in the String object has the following layout:
*
*
* - [0]: flags, flags & 0x1 = is proto2?, flags & 0x2 = is message?, flags & 0x4 = is
* edition?
*
- [1]: field count, if 0, this is the end of the integer sequence and the corresponding
* Object[] array should be null.
*
- [2]: oneof count
*
- [3]: hasbits count, how many hasbits integers are generated.
*
- [4]: min field number
*
- [5]: max field number
*
- [6]: total number of entries need to allocate
*
- [7]: map field count
*
- [8]: repeated field count, this doesn't include map fields.
*
- [9]: size of checkInitialized array
*
- [...]: field entries
*
*
* Each field entry starts with a field number and the field type:
*
*
* - [0]: field number
*
- [1]: field type with extra bits:
*
* - v & 0xFF = field type as defined in the FieldType class
*
- v & 0x0100 = is required?
*
- v & 0x0200 = is checkUtf8?
*
- v & 0x0400 = needs isInitialized check?
*
- v & 0x0800 = is enum field or map field enum value with legacy closedness?
*
- v & 0x1000 = supports presence checking?
*
*
*
* If the (singular) field supports presence checking:
*
*
* - [2]: hasbits offset
*
*
* If the field is in an oneof:
*
*
* - [2]: oneof index
*
*
* For other types, the field entry only has field number and field type.
*
* The Object[] array has 3 sections:
*
*
* - ---- oneof section ----
*
* - [0]: value field for oneof 1.
*
- [1]: case field for oneof 1.
*
- ...
*
- [.]: value field for oneof n.
*
- [.]: case field for oneof n.
*
* - ---- hasbits section ----
*
* - [.]: hasbits field 1
*
- [.]: hasbits field 2
*
- ...
*
- [.]: hasbits field n
*
* - ---- field section ----
*
* - [...]: field entries
*
*
*
* In the Object[] array, field entries are ordered in the same way as field entries in the
* String object. The size of each entry is determined by the field type.
*
*
* - Oneof field:
*
* - Oneof message field:
*
* - [0]: message class reference.
*
* - Oneof enum fieldin proto2:
*
* - [0]: EnumLiteMap
*
* - For all other oneof fields, field entry in the Object[] array is empty.
*
* - Repeated message field:
*
* - [0]: field reference
*
- [1]: message class reference
*
* - Proto2 singular/repeated enum field:
*
* - [0]: field reference
*
- [1]: EnumLiteMap
*
* - Map field with a proto2 enum value:
*
* - [0]: field reference
*
- [1]: map default entry instance
*
- [2]: EnumLiteMap
*
* - Map field with other value types:
*
* - [0]: field reference
*
- [1]: map default entry instance
*
* - All other field type:
*
* - [0]: field reference
*
*
*
* In order to read the field info from this compact format, a reader needs to progress through
* the String object and the Object[] array simultaneously.
*/
private final String info;
private final Object[] objects;
private final int flags;
RawMessageInfo(MessageLite defaultInstance, String info, Object[] objects) {
this.defaultInstance = defaultInstance;
this.info = info;
this.objects = objects;
int position = 0;
int value = (int) info.charAt(position++);
if (value < 0xD800) {
flags = value;
} else {
int result = value & 0x1FFF;
int shift = 13;
while ((value = info.charAt(position++)) >= 0xD800) {
result |= (value & 0x1FFF) << shift;
shift += 13;
}
flags = result | (value << shift);
}
}
String getStringInfo() {
return info;
}
Object[] getObjects() {
return objects;
}
@Override
public MessageLite getDefaultInstance() {
return defaultInstance;
}
@Override
public ProtoSyntax getSyntax() {
if ((flags & IS_PROTO2_BIT) != 0) {
return ProtoSyntax.PROTO2;
} else if ((flags & IS_EDITION_BIT) == 0x4) {
return ProtoSyntax.EDITIONS;
} else {
return ProtoSyntax.PROTO3;
}
}
@Override
public boolean isMessageSetWireFormat() {
return (flags & 0x2) == 0x2;
}
}