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Removes template magic to build up containers. 

Instead, we now put the attributes of the container into members.

llvm-svn: 148302
This commit is contained in:
Manuel Klimek 2012-01-17 09:34:07 +00:00
parent 86c3807b99
commit 85d26f9807
2 changed files with 212 additions and 131 deletions
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254
llvm/include/llvm/Support/JSONParser.h
View File

@ -22,11 +22,13 @@
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/SourceMgr.h"
namespace llvm {
class JSONContainer;
class JSONString;
class JSONValue;
class JSONKeyValuePair;
@ -50,10 +52,6 @@ protected:
private:
Kind MyKind;
friend class JSONParser;
friend class JSONKeyValuePair;
template <typename, char, char, JSONAtom::Kind> friend class JSONContainer;
};
/// \brief A parser for JSON text.
@ -100,14 +98,15 @@ private:
JSONKeyValuePair *parseKeyValuePair();
/// @}
/// \brief Templated helpers to parse the elements out of both forms of JSON
/// containers.
/// \brief Helpers to parse the elements out of both forms of containers.
/// @{
template <typename AtomT> AtomT *parseElement();
template <typename AtomT, char StartChar, char EndChar>
StringRef::iterator parseFirstElement(const AtomT *&Element);
template <typename AtomT, char EndChar>
StringRef::iterator parseNextElement(const AtomT *&Element);
const JSONAtom *parseElement(JSONAtom::Kind ContainerKind);
StringRef::iterator parseFirstElement(JSONAtom::Kind ContainerKind,
char StartChar, char EndChar,
const JSONAtom *&Element);
StringRef::iterator parseNextElement(JSONAtom::Kind ContainerKind,
char EndChar,
const JSONAtom *&Element);
/// @}
/// \brief Whitespace parsing.
@ -125,17 +124,7 @@ private:
/// }
/// \brief Skips all elements in the given container.
template <typename ContainerT>
bool skipContainer(const ContainerT &Container) {
for (typename ContainerT::const_iterator I = Container.current(),
E = Container.end();
I != E; ++I) {
assert(*I != 0);
if (!skip(**I))
return false;
}
return !failed();
}
bool skipContainer(const JSONContainer &Container);
/// \brief Skips to the next position behind the given JSON atom.
bool skip(const JSONAtom &Atom);
@ -160,8 +149,6 @@ private:
/// \brief If true, an error has occurred.
bool Failed;
template <typename AtomT, char StartChar, char EndChar,
JSONAtom::Kind ContainerKind>
friend class JSONContainer;
};
@ -210,7 +197,6 @@ private:
StringRef RawText;
friend class JSONAtom;
friend class JSONParser;
public:
@ -237,9 +223,7 @@ private:
JSONKeyValuePair(const JSONString *Key, const JSONValue *Value)
: JSONAtom(JK_KeyValuePair), Key(Key), Value(Value) {}
friend class JSONAtom;
friend class JSONParser;
template <typename, char, char, JSONAtom::Kind> friend class JSONContainer;
public:
/// \brief dyn_cast helpers
@ -255,41 +239,43 @@ public:
///
/// JSONContainers drive the lazy parsing of JSON arrays and objects via
/// forward iterators.
template <typename AtomT, char StartChar, char EndChar,
JSONAtom::Kind ContainerKind>
class JSONContainer : public JSONValue {
public:
private:
/// \brief An iterator that parses the underlying container during iteration.
///
/// Iterators on the same collection use shared state, so when multiple copies
/// of an iterator exist, only one is allowed to be used for iteration;
/// iterating multiple copies of an iterator of the same collection will lead
/// to undefined behavior.
class const_iterator : public std::iterator<std::forward_iterator_tag,
const AtomT*> {
class AtomIterator {
public:
const_iterator(const const_iterator &I) : Container(I.Container) {}
AtomIterator(const AtomIterator &I) : Container(I.Container) {}
bool operator==(const const_iterator &I) const {
/// \brief Iterator interface.
///@{
bool operator==(const AtomIterator &I) const {
if (isEnd() || I.isEnd())
return isEnd() == I.isEnd();
return Container->Position == I.Container->Position;
}
bool operator!=(const const_iterator &I) const { return !(*this == I); }
const_iterator &operator++() {
bool operator!=(const AtomIterator &I) const {
return !(*this == I);
}
AtomIterator &operator++() {
Container->parseNextElement();
return *this;
}
const AtomT *operator*() { return Container->Current; }
const JSONAtom *operator*() {
return Container->Current;
}
///@}
private:
/// \brief Create an iterator for which 'isEnd' returns true.
const_iterator() : Container(0) {}
AtomIterator() : Container(0) {}
/// \brief Create an iterator for the given container.
const_iterator(const JSONContainer *Container) : Container(Container) {}
AtomIterator(const JSONContainer *Container) : Container(Container) {}
bool isEnd() const {
return Container == 0 || Container->Position == StringRef::iterator();
@ -300,34 +286,62 @@ public:
friend class JSONContainer;
};
protected:
/// \brief An iterator for the specified AtomT.
///
/// Used for the implementation of iterators for JSONArray and JSONObject.
template <typename AtomT>
class IteratorTemplate : public std::iterator<std::forward_iterator_tag,
const AtomT*> {
public:
explicit IteratorTemplate(const AtomIterator& AtomI)
: AtomI(AtomI) {}
bool operator==(const IteratorTemplate &I) const {
return AtomI == I.AtomI;
}
bool operator!=(const IteratorTemplate &I) const { return !(*this == I); }
IteratorTemplate &operator++() {
++AtomI;
return *this;
}
const AtomT *operator*() { return dyn_cast<AtomT>(*AtomI); }
private:
AtomIterator AtomI;
};
JSONContainer(JSONParser *Parser, char StartChar, char EndChar,
JSONAtom::Kind ContainerKind)
: JSONValue(ContainerKind), Parser(Parser),
Position(), Current(0), Started(false),
StartChar(StartChar), EndChar(EndChar) {}
/// \brief Returns a lazy parsing iterator over the container.
///
/// As the iterator drives the parse stream, begin() must only be called
/// once per container.
const_iterator begin() const {
AtomIterator atom_begin() const {
if (Started)
report_fatal_error("Cannot parse container twice.");
Started = true;
// Set up the position and current element when we begin iterating over the
// container.
Position = Parser->parseFirstElement<AtomT, StartChar, EndChar>(Current);
return const_iterator(this);
Position = Parser->parseFirstElement(getKind(), StartChar, EndChar, Current);
return AtomIterator(this);
}
const_iterator end() const {
return const_iterator();
AtomIterator atom_end() const {
return AtomIterator();
}
private:
JSONContainer(JSONParser *Parser)
: JSONValue(ContainerKind), Parser(Parser),
Position(), Current(0), Started(false) {}
const_iterator current() const {
AtomIterator atom_current() const {
if (!Started)
return begin();
return atom_begin();
return const_iterator(this);
return AtomIterator(this);
}
/// \brief Parse the next element in the container into the Current element.
@ -337,7 +351,7 @@ private:
/// the next atom of the container.
void parseNextElement() const {
Parser->skip(*Current);
Position = Parser->parseNextElement<AtomT, EndChar>(Current);
Position = Parser->parseNextElement(getKind(), EndChar, Current);
}
// For parsing, JSONContainers call back into the JSONParser.
@ -347,95 +361,87 @@ private:
// for iterators on the container, they don't change the container's elements
// and are thus marked as mutable.
mutable StringRef::iterator Position;
mutable const AtomT *Current;
mutable const JSONAtom *Current;
mutable bool Started;
friend class JSONAtom;
const char StartChar;
const char EndChar;
friend class JSONParser;
friend class const_iterator;
public:
/// \brief dyn_cast helpers
///@{
static bool classof(const JSONAtom *Atom) {
return Atom->getKind() == ContainerKind;
switch (Atom->getKind()) {
case JK_Array:
case JK_Object:
return true;
case JK_KeyValuePair:
case JK_String:
return false;
};
llvm_unreachable("Invalid JSONAtom kind");
}
static bool classof(const JSONContainer *Container) { return true; }
///@}
};
/// \brief A simple JSON array.
typedef JSONContainer<JSONValue, '[', ']', JSONAtom::JK_Array> JSONArray;
class JSONArray : public JSONContainer {
public:
typedef IteratorTemplate<JSONValue> const_iterator;
/// \brief Returns a lazy parsing iterator over the container.
///
/// As the iterator drives the parse stream, begin() must only be called
/// once per container.
const_iterator begin() const { return const_iterator(atom_begin()); }
const_iterator end() const { return const_iterator(atom_end()); }
private:
JSONArray(JSONParser *Parser)
: JSONContainer(Parser, '[', ']', JSONAtom::JK_Array) {}
public:
/// \brief dyn_cast helpers
///@{
static bool classof(const JSONAtom *Atom) {
return Atom->getKind() == JSONAtom::JK_Array;
}
static bool classof(const JSONArray *Array) { return true; }
///@}
friend class JSONParser;
};
/// \brief A JSON object: an iterable list of JSON key-value pairs.
typedef JSONContainer<JSONKeyValuePair, '{', '}', JSONAtom::JK_Object>
JSONObject;
class JSONObject : public JSONContainer {
public:
typedef IteratorTemplate<JSONKeyValuePair> const_iterator;
/// \brief Template adaptor to dispatch element parsing for values.
template <> JSONValue *JSONParser::parseElement();
/// \brief Returns a lazy parsing iterator over the container.
///
/// As the iterator drives the parse stream, begin() must only be called
/// once per container.
const_iterator begin() const { return const_iterator(atom_begin()); }
const_iterator end() const { return const_iterator(atom_end()); }
/// \brief Template adaptor to dispatch element parsing for key value pairs.
template <> JSONKeyValuePair *JSONParser::parseElement();
private:
JSONObject(JSONParser *Parser)
: JSONContainer(Parser, '{', '}', JSONAtom::JK_Object) {}
/// \brief Parses the first element of a JSON array or object, or closes the
/// array.
///
/// The method assumes that the current position is before the first character
/// of the element, with possible white space in between. When successful, it
/// returns the new position after parsing the element. Otherwise, if there is
/// no next value, it returns a default constructed StringRef::iterator.
template <typename AtomT, char StartChar, char EndChar>
StringRef::iterator JSONParser::parseFirstElement(const AtomT *&Element) {
assert(*Position == StartChar);
Element = 0;
nextNonWhitespace();
if (errorIfAtEndOfFile("value or end of container at start of container"))
return StringRef::iterator();
if (*Position == EndChar)
return StringRef::iterator();
Element = parseElement<AtomT>();
if (Element == 0)
return StringRef::iterator();
return Position;
}
/// \brief Parses the next element of a JSON array or object, or closes the
/// array.
///
/// The method assumes that the current position is before the ',' which
/// separates the next element from the current element. When successful, it
/// returns the new position after parsing the element. Otherwise, if there is
/// no next value, it returns a default constructed StringRef::iterator.
template <typename AtomT, char EndChar>
StringRef::iterator JSONParser::parseNextElement(const AtomT *&Element) {
Element = 0;
nextNonWhitespace();
if (errorIfAtEndOfFile("',' or end of container for next element"))
return 0;
switch (*Position) {
case ',':
nextNonWhitespace();
if (errorIfAtEndOfFile("element in container"))
return StringRef::iterator();
Element = parseElement<AtomT>();
if (Element == 0)
return StringRef::iterator();
return Position;
case EndChar:
return StringRef::iterator();
default:
setExpectedError("',' or end of container for next element", *Position);
return StringRef::iterator();
public:
/// \brief dyn_cast helpers
///@{
static bool classof(const JSONAtom *Atom) {
return Atom->getKind() == JSONAtom::JK_Object;
}
}
static bool classof(const JSONObject *Object) { return true; }
///@}
friend class JSONParser;
};
} // end namespace llvm

89
llvm/lib/Support/JSONParser.cpp
View File

@ -55,9 +55,11 @@ bool JSONParser::validate() {
bool JSONParser::skip(const JSONAtom &Atom) {
switch(Atom.getKind()) {
case JSONAtom::JK_Array: return skipContainer(*cast<JSONArray>(&Atom));
case JSONAtom::JK_Object: return skipContainer(*cast<JSONObject>(&Atom));
case JSONAtom::JK_String: return true;
case JSONAtom::JK_Array:
case JSONAtom::JK_Object:
return skipContainer(*cast<JSONContainer>(&Atom));
case JSONAtom::JK_String:
return true;
case JSONAtom::JK_KeyValuePair:
return skip(*cast<JSONKeyValuePair>(&Atom)->Value);
}
@ -218,10 +220,83 @@ JSONKeyValuePair *JSONParser::parseKeyValuePair() {
JSONKeyValuePair(Key, Value);
}
template <> JSONValue *JSONParser::parseElement() {
return parseValue();
/// \brief Parses the first element of a JSON array or object, or closes the
/// array.
///
/// The method assumes that the current position is before the first character
/// of the element, with possible white space in between. When successful, it
/// returns the new position after parsing the element. Otherwise, if there is
/// no next value, it returns a default constructed StringRef::iterator.
StringRef::iterator JSONParser::parseFirstElement(JSONAtom::Kind ContainerKind,
char StartChar, char EndChar,
const JSONAtom *&Element) {
assert(*Position == StartChar);
Element = 0;
nextNonWhitespace();
if (errorIfAtEndOfFile("value or end of container at start of container"))
return StringRef::iterator();
if (*Position == EndChar)
return StringRef::iterator();
Element = parseElement(ContainerKind);
if (Element == 0)
return StringRef::iterator();
return Position;
}
template <> JSONKeyValuePair *JSONParser::parseElement() {
return parseKeyValuePair();
/// \brief Parses the next element of a JSON array or object, or closes the
/// array.
///
/// The method assumes that the current position is before the ',' which
/// separates the next element from the current element. When successful, it
/// returns the new position after parsing the element. Otherwise, if there is
/// no next value, it returns a default constructed StringRef::iterator.
StringRef::iterator JSONParser::parseNextElement(JSONAtom::Kind ContainerKind,
char EndChar,
const JSONAtom *&Element) {
Element = 0;
nextNonWhitespace();
if (errorIfAtEndOfFile("',' or end of container for next element"))
return 0;
if (*Position == ',') {
nextNonWhitespace();
if (errorIfAtEndOfFile("element in container"))
return StringRef::iterator();
Element = parseElement(ContainerKind);
if (Element == 0)
return StringRef::iterator();
return Position;
} else if (*Position == EndChar) {
return StringRef::iterator();
} else {
setExpectedError("',' or end of container for next element", *Position);
return StringRef::iterator();
}
}
const JSONAtom *JSONParser::parseElement(JSONAtom::Kind ContainerKind) {
switch (ContainerKind) {
case JSONAtom::JK_Array:
return parseValue();
case JSONAtom::JK_Object:
return parseKeyValuePair();
default:
llvm_unreachable("Impossible code path");
}
}
bool JSONParser::skipContainer(const JSONContainer &Container) {
for (JSONContainer::AtomIterator I = Container.atom_current(),
E = Container.atom_end();
I != E; ++I) {
assert(*I != 0);
if (!skip(**I))
return false;
}
return !failed();
}