capnproto-java-rpc/runtime/src/main/java/org/capnproto/MessageBuilder.java
2020-10-22 15:55:11 +01:00

120 lines
4.8 KiB
Java

// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
// Licensed under the MIT License:
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package org.capnproto;
public final class MessageBuilder {
private final BuilderArena arena;
public MessageBuilder() {
this.arena = new BuilderArena(BuilderArena.SUGGESTED_FIRST_SEGMENT_WORDS,
BuilderArena.SUGGESTED_ALLOCATION_STRATEGY);
}
public MessageBuilder(int firstSegmentWords) {
this.arena = new BuilderArena(firstSegmentWords,
BuilderArena.SUGGESTED_ALLOCATION_STRATEGY);
}
public MessageBuilder(int firstSegmentWords, BuilderArena.AllocationStrategy allocationStrategy) {
this.arena = new BuilderArena(firstSegmentWords,
allocationStrategy);
}
/**
* Constructs a new MessageBuilder from an Allocator.
*/
public MessageBuilder(Allocator allocator) {
this.arena = new BuilderArena(allocator);
}
/**
* Constructs a new MessageBuilder from an Allocator and a given first segment buffer.
* This is useful for reusing the first segment buffer between messages, to avoid
* repeated allocations.
*
* You MUST ensure that firstSegment contains only zeroes before calling this method.
* If you are reusing firstSegment from another message, then it suffices to call
* clearFirstSegment() on that message.
*/
public MessageBuilder(Allocator allocator, java.nio.ByteBuffer firstSegment) {
this.arena = new BuilderArena(allocator, firstSegment);
}
/**
* Like the previous constructor, but uses a DefaultAllocator.
*
* You MUST ensure that firstSegment contains only zeroes before calling this method.
* If you are reusing firstSegment from another message, then it suffices to call
* clearFirstSegment() on that message.
*/
public MessageBuilder(java.nio.ByteBuffer firstSegment) {
this.arena = new BuilderArena(new DefaultAllocator(), firstSegment);
}
private AnyPointer.Builder getRootInternal() {
if (this.arena.segments.isEmpty()) {
this.arena.allocate(1);
}
SegmentBuilder rootSegment = this.arena.segments.get(0);
if (rootSegment.currentSize() == 0) {
int location = rootSegment.allocate(1);
if (location == SegmentBuilder.FAILED_ALLOCATION) {
throw new RuntimeException("could not allocate root pointer");
}
if (location != 0) {
throw new RuntimeException("First allocated word of new segment was not at offset 0");
}
return new AnyPointer.Builder(rootSegment, this.arena.getLocalCapTable(), location);
} else {
return new AnyPointer.Builder(rootSegment, this.arena.getLocalCapTable(), 0);
}
}
public <T> T getRoot(FromPointerBuilder<T> factory) {
return this.getRootInternal().getAs(factory);
}
public <T, U> void setRoot(SetPointerBuilder<T, U> factory, U reader) {
this.getRootInternal().setAs(factory, reader);
}
public <T> T initRoot(FromPointerBuilder<T> factory) {
return this.getRootInternal().initAs(factory);
}
public final java.nio.ByteBuffer[] getSegmentsForOutput() {
return this.arena.getSegmentsForOutput();
}
/**
* Sets the first segment buffer to contain all zeros so that it can be reused in
* another message. (See the MessageBuilder(Allocator, ByteBuffer) constructor above.)
*
* After calling this method, the message will be corrupted. Therefore, you need to make
* sure to write the message (via getSegmentsForOutput()) before calling this.
*/
public final void clearFirstSegment() {
this.arena.segments.get(0).clear();
}
}