1//===- YAMLParser.h - Simple YAML parser ------------------------*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This is a YAML 1.2 parser.
11//
12// See http://www.yaml.org/spec/1.2/spec.html for the full standard.
13//
14// This currently does not implement the following:
15// * Multi-line literal folding.
16// * Tag resolution.
17// * UTF-16.
18// * BOMs anywhere other than the first Unicode scalar value in the file.
19//
20// The most important class here is Stream. This represents a YAML stream with
21// 0, 1, or many documents.
22//
23// SourceMgr sm;
24// StringRef input = getInput();
25// yaml::Stream stream(input, sm);
26//
27// for (yaml::document_iterator di = stream.begin(), de = stream.end();
28// di != de; ++di) {
29// yaml::Node *n = di->getRoot();
30// if (n) {
31// // Do something with n...
32// } else
33// break;
34// }
35//
36//===----------------------------------------------------------------------===//
37
38#ifndef LLVM_SUPPORT_YAMLPARSER_H
39#define LLVM_SUPPORT_YAMLPARSER_H
40
41#include "llvm/ADT/StringRef.h"
42#include "llvm/Support/Allocator.h"
43#include "llvm/Support/SMLoc.h"
44#include <cassert>
45#include <cstddef>
46#include <iterator>
47#include <map>
48#include <memory>
49#include <string>
50#include <system_error>
51
52namespace llvm {
53
54class MemoryBufferRef;
55class SourceMgr;
56class raw_ostream;
57class Twine;
58
59namespace yaml {
60
61class Document;
62class document_iterator;
63class Node;
64class Scanner;
65struct Token;
66
67/// Dump all the tokens in this stream to OS.
68/// \returns true if there was an error, false otherwise.
69bool dumpTokens(StringRef Input, raw_ostream &);
70
71/// Scans all tokens in input without outputting anything. This is used
72/// for benchmarking the tokenizer.
73/// \returns true if there was an error, false otherwise.
74bool scanTokens(StringRef Input);
75
76/// Escape \a Input for a double quoted scalar; if \p EscapePrintable
77/// is true, all UTF8 sequences will be escaped, if \p EscapePrintable is
78/// false, those UTF8 sequences encoding printable unicode scalars will not be
79/// escaped, but emitted verbatim.
80std::string escape(StringRef Input, bool EscapePrintable = true);
81
82/// This class represents a YAML stream potentially containing multiple
83/// documents.
84class Stream {
85public:
86 /// This keeps a reference to the string referenced by \p Input.
87 Stream(StringRef Input, SourceMgr &, bool ShowColors = true,
88 std::error_code *EC = nullptr);
89
90 Stream(MemoryBufferRef InputBuffer, SourceMgr &, bool ShowColors = true,
91 std::error_code *EC = nullptr);
92 ~Stream();
93
94 document_iterator begin();
95 document_iterator end();
96 void skip();
97 bool failed();
98
99 bool validate() {
100 skip();
101 return !failed();
102 }
103
104 void printError(Node *N, const Twine &Msg);
105
106private:
107 friend class Document;
108
109 std::unique_ptr<Scanner> scanner;
110 std::unique_ptr<Document> CurrentDoc;
111};
112
113/// Abstract base class for all Nodes.
114class Node {
115 virtual void anchor();
116
117public:
118 enum NodeKind {
119 NK_Null,
120 NK_Scalar,
121 NK_BlockScalar,
122 NK_KeyValue,
123 NK_Mapping,
124 NK_Sequence,
125 NK_Alias
126 };
127
128 Node(unsigned int Type, std::unique_ptr<Document> &, StringRef Anchor,
129 StringRef Tag);
130
131 // It's not safe to copy YAML nodes; the document is streamed and the position
132 // is part of the state.
133 Node(const Node &) = delete;
134 void operator=(const Node &) = delete;
135
136 void *operator new(size_t Size, BumpPtrAllocator &Alloc,
137 size_t Alignment = 16) noexcept {
138 return Alloc.Allocate(Size, Alignment);
139 }
140
141 void operator delete(void *Ptr, BumpPtrAllocator &Alloc,
142 size_t Size) noexcept {
143 Alloc.Deallocate(Ptr, Size);
144 }
145
146 void operator delete(void *) noexcept = delete;
147
148 /// Get the value of the anchor attached to this node. If it does not
149 /// have one, getAnchor().size() will be 0.
150 StringRef getAnchor() const { return Anchor; }
151
152 /// Get the tag as it was written in the document. This does not
153 /// perform tag resolution.
154 StringRef getRawTag() const { return Tag; }
155
156 /// Get the verbatium tag for a given Node. This performs tag resoluton
157 /// and substitution.
158 std::string getVerbatimTag() const;
159
160 SMRange getSourceRange() const { return SourceRange; }
161 void setSourceRange(SMRange SR) { SourceRange = SR; }
162
163 // These functions forward to Document and Scanner.
164 Token &peekNext();
165 Token getNext();
166 Node *parseBlockNode();
167 BumpPtrAllocator &getAllocator();
168 void setError(const Twine &Message, Token &Location) const;
169 bool failed() const;
170
171 virtual void skip() {}
172
173 unsigned int getType() const { return TypeID; }
174
175protected:
176 std::unique_ptr<Document> &Doc;
177 SMRange SourceRange;
178
179 ~Node() = default;
180
181private:
182 unsigned int TypeID;
183 StringRef Anchor;
184 /// The tag as typed in the document.
185 StringRef Tag;
186};
187
188/// A null value.
189///
190/// Example:
191/// !!null null
192class NullNode final : public Node {
193 void anchor() override;
194
195public:
196 NullNode(std::unique_ptr<Document> &D)
197 : Node(NK_Null, D, StringRef(), StringRef()) {}
198
199 static bool classof(const Node *N) { return N->getType() == NK_Null; }
200};
201
202/// A scalar node is an opaque datum that can be presented as a
203/// series of zero or more Unicode scalar values.
204///
205/// Example:
206/// Adena
207class ScalarNode final : public Node {
208 void anchor() override;
209
210public:
211 ScalarNode(std::unique_ptr<Document> &D, StringRef Anchor, StringRef Tag,
212 StringRef Val)
213 : Node(NK_Scalar, D, Anchor, Tag), Value(Val) {
214 SMLoc Start = SMLoc::getFromPointer(Val.begin());
215 SMLoc End = SMLoc::getFromPointer(Val.end());
216 SourceRange = SMRange(Start, End);
217 }
218
219 // Return Value without any escaping or folding or other fun YAML stuff. This
220 // is the exact bytes that are contained in the file (after conversion to
221 // utf8).
222 StringRef getRawValue() const { return Value; }
223
224 /// Gets the value of this node as a StringRef.
225 ///
226 /// \param Storage is used to store the content of the returned StringRef iff
227 /// it requires any modification from how it appeared in the source.
228 /// This happens with escaped characters and multi-line literals.
229 StringRef getValue(SmallVectorImpl<char> &Storage) const;
230
231 static bool classof(const Node *N) {
232 return N->getType() == NK_Scalar;
233 }
234
235private:
236 StringRef Value;
237
238 StringRef unescapeDoubleQuoted(StringRef UnquotedValue,
239 StringRef::size_type Start,
240 SmallVectorImpl<char> &Storage) const;
241};
242
243/// A block scalar node is an opaque datum that can be presented as a
244/// series of zero or more Unicode scalar values.
245///
246/// Example:
247/// |
248/// Hello
249/// World
250class BlockScalarNode final : public Node {
251 void anchor() override;
252
253public:
254 BlockScalarNode(std::unique_ptr<Document> &D, StringRef Anchor, StringRef Tag,
255 StringRef Value, StringRef RawVal)
256 : Node(NK_BlockScalar, D, Anchor, Tag), Value(Value) {
257 SMLoc Start = SMLoc::getFromPointer(RawVal.begin());
258 SMLoc End = SMLoc::getFromPointer(RawVal.end());
259 SourceRange = SMRange(Start, End);
260 }
261
262 /// Gets the value of this node as a StringRef.
263 StringRef getValue() const { return Value; }
264
265 static bool classof(const Node *N) {
266 return N->getType() == NK_BlockScalar;
267 }
268
269private:
270 StringRef Value;
271};
272
273/// A key and value pair. While not technically a Node under the YAML
274/// representation graph, it is easier to treat them this way.
275///
276/// TODO: Consider making this not a child of Node.
277///
278/// Example:
279/// Section: .text
280class KeyValueNode final : public Node {
281 void anchor() override;
282
283public:
284 KeyValueNode(std::unique_ptr<Document> &D)
285 : Node(NK_KeyValue, D, StringRef(), StringRef()) {}
286
287 /// Parse and return the key.
288 ///
289 /// This may be called multiple times.
290 ///
291 /// \returns The key, or nullptr if failed() == true.
292 Node *getKey();
293
294 /// Parse and return the value.
295 ///
296 /// This may be called multiple times.
297 ///
298 /// \returns The value, or nullptr if failed() == true.
299 Node *getValue();
300
301 void skip() override {
302 if (Node *Key = getKey()) {
303 Key->skip();
304 if (Node *Val = getValue())
305 Val->skip();
306 }
307 }
308
309 static bool classof(const Node *N) {
310 return N->getType() == NK_KeyValue;
311 }
312
313private:
314 Node *Key = nullptr;
315 Node *Value = nullptr;
316};
317
318/// This is an iterator abstraction over YAML collections shared by both
319/// sequences and maps.
320///
321/// BaseT must have a ValueT* member named CurrentEntry and a member function
322/// increment() which must set CurrentEntry to 0 to create an end iterator.
323template <class BaseT, class ValueT>
324class basic_collection_iterator
325 : public std::iterator<std::input_iterator_tag, ValueT> {
326public:
327 basic_collection_iterator() = default;
328 basic_collection_iterator(BaseT *B) : Base(B) {}
329
330 ValueT *operator->() const {
331 assert(Base && Base->CurrentEntry && "Attempted to access end iterator!");
332 return Base->CurrentEntry;
333 }
334
335 ValueT &operator*() const {
336 assert(Base && Base->CurrentEntry &&
337 "Attempted to dereference end iterator!");
338 return *Base->CurrentEntry;
339 }
340
341 operator ValueT *() const {
342 assert(Base && Base->CurrentEntry && "Attempted to access end iterator!");
343 return Base->CurrentEntry;
344 }
345
346 /// Note on EqualityComparable:
347 ///
348 /// The iterator is not re-entrant,
349 /// it is meant to be used for parsing YAML on-demand
350 /// Once iteration started - it can point only to one entry at a time
351 /// hence Base.CurrentEntry and Other.Base.CurrentEntry are equal
352 /// iff Base and Other.Base are equal.
353 bool operator==(const basic_collection_iterator &Other) const {
354 if (Base && (Base == Other.Base)) {
355 assert((Base->CurrentEntry == Other.Base->CurrentEntry)
356 && "Equal Bases expected to point to equal Entries");
357 }
358
359 return Base == Other.Base;
360 }
361
362 bool operator!=(const basic_collection_iterator &Other) const {
363 return !(Base == Other.Base);
364 }
365
366 basic_collection_iterator &operator++() {
367 assert(Base && "Attempted to advance iterator past end!");
368 Base->increment();
369 // Create an end iterator.
370 if (!Base->CurrentEntry)
371 Base = nullptr;
372 return *this;
373 }
374
375private:
376 BaseT *Base = nullptr;
377};
378
379// The following two templates are used for both MappingNode and Sequence Node.
380template <class CollectionType>
381typename CollectionType::iterator begin(CollectionType &C) {
382 assert(C.IsAtBeginning && "You may only iterate over a collection once!");
383 C.IsAtBeginning = false;
384 typename CollectionType::iterator ret(&C);
385 ++ret;
386 return ret;
387}
388
389template <class CollectionType> void skip(CollectionType &C) {
390 // TODO: support skipping from the middle of a parsed collection ;/
391 assert((C.IsAtBeginning || C.IsAtEnd) && "Cannot skip mid parse!");
392 if (C.IsAtBeginning)
393 for (typename CollectionType::iterator i = begin(C), e = C.end(); i != e;
394 ++i)
395 i->skip();
396}
397
398/// Represents a YAML map created from either a block map for a flow map.
399///
400/// This parses the YAML stream as increment() is called.
401///
402/// Example:
403/// Name: _main
404/// Scope: Global
405class MappingNode final : public Node {
406 void anchor() override;
407
408public:
409 enum MappingType {
410 MT_Block,
411 MT_Flow,
412 MT_Inline ///< An inline mapping node is used for "[key: value]".
413 };
414
415 MappingNode(std::unique_ptr<Document> &D, StringRef Anchor, StringRef Tag,
416 MappingType MT)
417 : Node(NK_Mapping, D, Anchor, Tag), Type(MT) {}
418
419 friend class basic_collection_iterator<MappingNode, KeyValueNode>;
420
421 using iterator = basic_collection_iterator<MappingNode, KeyValueNode>;
422
423 template <class T> friend typename T::iterator yaml::begin(T &);
424 template <class T> friend void yaml::skip(T &);
425
426 iterator begin() { return yaml::begin(*this); }
427
428 iterator end() { return iterator(); }
429
430 void skip() override { yaml::skip(*this); }
431
432 static bool classof(const Node *N) {
433 return N->getType() == NK_Mapping;
434 }
435
436private:
437 MappingType Type;
438 bool IsAtBeginning = true;
439 bool IsAtEnd = false;
440 KeyValueNode *CurrentEntry = nullptr;
441
442 void increment();
443};
444
445/// Represents a YAML sequence created from either a block sequence for a
446/// flow sequence.
447///
448/// This parses the YAML stream as increment() is called.
449///
450/// Example:
451/// - Hello
452/// - World
453class SequenceNode final : public Node {
454 void anchor() override;
455
456public:
457 enum SequenceType {
458 ST_Block,
459 ST_Flow,
460 // Use for:
461 //
462 // key:
463 // - val1
464 // - val2
465 //
466 // As a BlockMappingEntry and BlockEnd are not created in this case.
467 ST_Indentless
468 };
469
470 SequenceNode(std::unique_ptr<Document> &D, StringRef Anchor, StringRef Tag,
471 SequenceType ST)
472 : Node(NK_Sequence, D, Anchor, Tag), SeqType(ST) {}
473
474 friend class basic_collection_iterator<SequenceNode, Node>;
475
476 using iterator = basic_collection_iterator<SequenceNode, Node>;
477
478 template <class T> friend typename T::iterator yaml::begin(T &);
479 template <class T> friend void yaml::skip(T &);
480
481 void increment();
482
483 iterator begin() { return yaml::begin(*this); }
484
485 iterator end() { return iterator(); }
486
487 void skip() override { yaml::skip(*this); }
488
489 static bool classof(const Node *N) {
490 return N->getType() == NK_Sequence;
491 }
492
493private:
494 SequenceType SeqType;
495 bool IsAtBeginning = true;
496 bool IsAtEnd = false;
497 bool WasPreviousTokenFlowEntry = true; // Start with an imaginary ','.
498 Node *CurrentEntry = nullptr;
499};
500
501/// Represents an alias to a Node with an anchor.
502///
503/// Example:
504/// *AnchorName
505class AliasNode final : public Node {
506 void anchor() override;
507
508public:
509 AliasNode(std::unique_ptr<Document> &D, StringRef Val)
510 : Node(NK_Alias, D, StringRef(), StringRef()), Name(Val) {}
511
512 StringRef getName() const { return Name; }
513 Node *getTarget();
514
515 static bool classof(const Node *N) { return N->getType() == NK_Alias; }
516
517private:
518 StringRef Name;
519};
520
521/// A YAML Stream is a sequence of Documents. A document contains a root
522/// node.
523class Document {
524public:
525 Document(Stream &ParentStream);
526
527 /// Root for parsing a node. Returns a single node.
528 Node *parseBlockNode();
529
530 /// Finish parsing the current document and return true if there are
531 /// more. Return false otherwise.
532 bool skip();
533
534 /// Parse and return the root level node.
535 Node *getRoot() {
536 if (Root)
537 return Root;
538 return Root = parseBlockNode();
539 }
540
541 const std::map<StringRef, StringRef> &getTagMap() const { return TagMap; }
542
543private:
544 friend class Node;
545 friend class document_iterator;
546
547 /// Stream to read tokens from.
548 Stream &stream;
549
550 /// Used to allocate nodes to. All are destroyed without calling their
551 /// destructor when the document is destroyed.
552 BumpPtrAllocator NodeAllocator;
553
554 /// The root node. Used to support skipping a partially parsed
555 /// document.
556 Node *Root;
557
558 /// Maps tag prefixes to their expansion.
559 std::map<StringRef, StringRef> TagMap;
560
561 Token &peekNext();
562 Token getNext();
563 void setError(const Twine &Message, Token &Location) const;
564 bool failed() const;
565
566 /// Parse %BLAH directives and return true if any were encountered.
567 bool parseDirectives();
568
569 /// Parse %YAML
570 void parseYAMLDirective();
571
572 /// Parse %TAG
573 void parseTAGDirective();
574
575 /// Consume the next token and error if it is not \a TK.
576 bool expectToken(int TK);
577};
578
579/// Iterator abstraction for Documents over a Stream.
580class document_iterator {
581public:
582 document_iterator() = default;
583 document_iterator(std::unique_ptr<Document> &D) : Doc(&D) {}
584
585 bool operator==(const document_iterator &Other) const {
586 if (isAtEnd() || Other.isAtEnd())
587 return isAtEnd() && Other.isAtEnd();
588
589 return Doc == Other.Doc;
590 }
591 bool operator!=(const document_iterator &Other) const {
592 return !(*this == Other);
593 }
594
595 document_iterator operator++() {
596 assert(Doc && "incrementing iterator past the end.");
597 if (!(*Doc)->skip()) {
598 Doc->reset(nullptr);
599 } else {
600 Stream &S = (*Doc)->stream;
601 Doc->reset(new Document(S));
602 }
603 return *this;
604 }
605
606 Document &operator*() { return *Doc->get(); }
607
608 std::unique_ptr<Document> &operator->() { return *Doc; }
609
610private:
611 bool isAtEnd() const { return !Doc || !*Doc; }
612
613 std::unique_ptr<Document> *Doc = nullptr;
614};
615
616} // end namespace yaml
617
618} // end namespace llvm
619
620#endif // LLVM_SUPPORT_YAMLPARSER_H
621