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llvm-mirror/lib/BinaryFormat/MsgPackDocument.cpp
2020-10-27 12:57:00 +01:00

315 lines
9.6 KiB
C++

//===-- MsgPackDocument.cpp - MsgPack Document --------------------------*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// This file implements a class that exposes a simple in-memory representation
/// of a document of MsgPack objects, that can be read from MsgPack, written to
/// MsgPack, and inspected and modified in memory. This is intended to be a
/// lighter-weight (in terms of memory allocations) replacement for
/// MsgPackTypes.
///
//===----------------------------------------------------------------------===//
#include "llvm/BinaryFormat/MsgPackDocument.h"
#include "llvm/BinaryFormat/MsgPackWriter.h"
using namespace llvm;
using namespace msgpack;
// Convert this DocNode into an empty array.
void DocNode::convertToArray() { *this = getDocument()->getArrayNode(); }
// Convert this DocNode into an empty map.
void DocNode::convertToMap() { *this = getDocument()->getMapNode(); }
/// Find the key in the MapDocNode.
DocNode::MapTy::iterator MapDocNode::find(StringRef S) {
return find(getDocument()->getNode(S));
}
/// Member access for MapDocNode. The string data must remain valid for the
/// lifetime of the Document.
DocNode &MapDocNode::operator[](StringRef S) {
return (*this)[getDocument()->getNode(S)];
}
/// Member access for MapDocNode.
DocNode &MapDocNode::operator[](DocNode Key) {
assert(!Key.isEmpty());
DocNode &N = (*Map)[Key];
if (N.isEmpty()) {
// Ensure a new element has its KindAndDoc initialized.
N = getDocument()->getEmptyNode();
}
return N;
}
/// Member access for MapDocNode for integer key.
DocNode &MapDocNode::operator[](int Key) {
return (*this)[getDocument()->getNode(Key)];
}
DocNode &MapDocNode::operator[](unsigned Key) {
return (*this)[getDocument()->getNode(Key)];
}
DocNode &MapDocNode::operator[](int64_t Key) {
return (*this)[getDocument()->getNode(Key)];
}
DocNode &MapDocNode::operator[](uint64_t Key) {
return (*this)[getDocument()->getNode(Key)];
}
/// Array element access. This extends the array if necessary.
DocNode &ArrayDocNode::operator[](size_t Index) {
if (size() <= Index) {
// Ensure new elements have their KindAndDoc initialized.
Array->resize(Index + 1, getDocument()->getEmptyNode());
}
return (*Array)[Index];
}
// Convenience assignment operators. This only works if the destination
// DocNode has an associated Document, i.e. it was not constructed using the
// default constructor. The string one does not copy, so the string must
// remain valid for the lifetime of the Document. Use fromString to avoid
// that restriction.
DocNode &DocNode::operator=(StringRef Val) {
*this = getDocument()->getNode(Val);
return *this;
}
DocNode &DocNode::operator=(bool Val) {
*this = getDocument()->getNode(Val);
return *this;
}
DocNode &DocNode::operator=(int Val) {
*this = getDocument()->getNode(Val);
return *this;
}
DocNode &DocNode::operator=(unsigned Val) {
*this = getDocument()->getNode(Val);
return *this;
}
DocNode &DocNode::operator=(int64_t Val) {
*this = getDocument()->getNode(Val);
return *this;
}
DocNode &DocNode::operator=(uint64_t Val) {
*this = getDocument()->getNode(Val);
return *this;
}
// A level in the document reading stack.
struct StackLevel {
StackLevel(DocNode Node, size_t StartIndex, size_t Length,
DocNode *MapEntry = nullptr)
: Node(Node), Index(StartIndex), End(StartIndex + Length),
MapEntry(MapEntry) {}
DocNode Node;
size_t Index;
size_t End;
// Points to map entry when we have just processed a map key.
DocNode *MapEntry;
DocNode MapKey;
};
// Read a document from a binary msgpack blob, merging into anything already in
// the Document.
// The blob data must remain valid for the lifetime of this Document (because a
// string object in the document contains a StringRef into the original blob).
// If Multi, then this sets root to an array and adds top-level objects to it.
// If !Multi, then it only reads a single top-level object, even if there are
// more, and sets root to that.
// Returns false if failed due to illegal format or merge error.
bool Document::readFromBlob(
StringRef Blob, bool Multi,
function_ref<int(DocNode *DestNode, DocNode SrcNode, DocNode MapKey)>
Merger) {
msgpack::Reader MPReader(Blob);
SmallVector<StackLevel, 4> Stack;
if (Multi) {
// Create the array for multiple top-level objects.
Root = getArrayNode();
Stack.push_back(StackLevel(Root, 0, (size_t)-1));
}
do {
// On to next element (or key if doing a map key next).
// Read the value.
Object Obj;
if (!MPReader.read(Obj)) {
if (Multi && Stack.size() == 1) {
// OK to finish here as we've just done a top-level element with Multi
break;
}
return false; // Finished too early
}
// Convert it into a DocNode.
DocNode Node;
switch (Obj.Kind) {
case Type::Nil:
Node = getNode();
break;
case Type::Int:
Node = getNode(Obj.Int);
break;
case Type::UInt:
Node = getNode(Obj.UInt);
break;
case Type::Boolean:
Node = getNode(Obj.Bool);
break;
case Type::Float:
Node = getNode(Obj.Float);
break;
case Type::String:
Node = getNode(Obj.Raw);
break;
case Type::Map:
Node = getMapNode();
break;
case Type::Array:
Node = getArrayNode();
break;
default:
return false; // Raw and Extension not supported
}
// Store it.
DocNode *DestNode = nullptr;
if (Stack.empty())
DestNode = &Root;
else if (Stack.back().Node.getKind() == Type::Array) {
// Reading an array entry.
auto &Array = Stack.back().Node.getArray();
DestNode = &Array[Stack.back().Index++];
} else {
auto &Map = Stack.back().Node.getMap();
if (!Stack.back().MapEntry) {
// Reading a map key.
Stack.back().MapKey = Node;
Stack.back().MapEntry = &Map[Node];
continue;
}
// Reading the value for the map key read in the last iteration.
DestNode = Stack.back().MapEntry;
Stack.back().MapEntry = nullptr;
++Stack.back().Index;
}
int MergeResult = 0;
if (!DestNode->isEmpty()) {
// In a merge, there is already a value at this position. Call the
// callback to attempt to resolve the conflict. The resolution must result
// in an array or map if Node is an array or map respectively.
DocNode MapKey = !Stack.empty() && !Stack.back().MapKey.isEmpty()
? Stack.back().MapKey
: getNode();
MergeResult = Merger(DestNode, Node, MapKey);
if (MergeResult < 0)
return false; // Merge conflict resolution failed
assert(!((Node.isMap() && !DestNode->isMap()) ||
(Node.isArray() && !DestNode->isArray())));
} else
*DestNode = Node;
// See if we're starting a new array or map.
switch (DestNode->getKind()) {
case msgpack::Type::Array:
case msgpack::Type::Map:
Stack.push_back(StackLevel(*DestNode, MergeResult, Obj.Length, nullptr));
break;
default:
break;
}
// Pop finished stack levels.
while (!Stack.empty()) {
if (Stack.back().MapEntry)
break;
if (Stack.back().Index != Stack.back().End)
break;
Stack.pop_back();
}
} while (!Stack.empty());
return true;
}
struct WriterStackLevel {
DocNode Node;
DocNode::MapTy::iterator MapIt;
DocNode::ArrayTy::iterator ArrayIt;
bool OnKey;
};
/// Write a MsgPack document to a binary MsgPack blob.
void Document::writeToBlob(std::string &Blob) {
Blob.clear();
raw_string_ostream OS(Blob);
msgpack::Writer MPWriter(OS);
SmallVector<WriterStackLevel, 4> Stack;
DocNode Node = getRoot();
for (;;) {
switch (Node.getKind()) {
case Type::Array:
MPWriter.writeArraySize(Node.getArray().size());
Stack.push_back(
{Node, DocNode::MapTy::iterator(), Node.getArray().begin(), false});
break;
case Type::Map:
MPWriter.writeMapSize(Node.getMap().size());
Stack.push_back(
{Node, Node.getMap().begin(), DocNode::ArrayTy::iterator(), true});
break;
case Type::Nil:
MPWriter.writeNil();
break;
case Type::Boolean:
MPWriter.write(Node.getBool());
break;
case Type::Int:
MPWriter.write(Node.getInt());
break;
case Type::UInt:
MPWriter.write(Node.getUInt());
break;
case Type::String:
MPWriter.write(Node.getString());
break;
case Type::Empty:
llvm_unreachable("unhandled empty msgpack node");
default:
llvm_unreachable("unhandled msgpack object kind");
}
// Pop finished stack levels.
while (!Stack.empty()) {
if (Stack.back().Node.getKind() == Type::Map) {
if (Stack.back().MapIt != Stack.back().Node.getMap().end())
break;
} else {
if (Stack.back().ArrayIt != Stack.back().Node.getArray().end())
break;
}
Stack.pop_back();
}
if (Stack.empty())
break;
// Get the next value.
if (Stack.back().Node.getKind() == Type::Map) {
if (Stack.back().OnKey) {
// Do the key of a key,value pair in a map.
Node = Stack.back().MapIt->first;
Stack.back().OnKey = false;
} else {
Node = Stack.back().MapIt->second;
++Stack.back().MapIt;
Stack.back().OnKey = true;
}
} else {
Node = *Stack.back().ArrayIt;
++Stack.back().ArrayIt;
}
}
}