1 //===---- QueryParser.cpp - clang-query command parser --------------------===//
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 #include "QueryParser.h"
11 #include "Query.h"
12 #include "QuerySession.h"
13 #include "clang/ASTMatchers/Dynamic/Parser.h"
14 #include "clang/Basic/CharInfo.h"
15 #include "llvm/ADT/StringRef.h"
16 #include "llvm/ADT/StringSwitch.h"
17 #include <set>
18 
19 using namespace llvm;
20 using namespace clang::ast_matchers::dynamic;
21 
22 namespace clang {
23 namespace query {
24 
25 // Lex any amount of whitespace followed by a "word" (any sequence of
26 // non-whitespace characters) from the start of region [Begin,End).  If no word
27 // is found before End, return StringRef().  Begin is adjusted to exclude the
28 // lexed region.
29 StringRef QueryParser::lexWord() {
30   while (true) {
31     if (Begin == End)
32       return StringRef(Begin, 0);
33 
34     if (!isWhitespace(*Begin))
35       break;
36 
37     ++Begin;
38   }
39 
40   const char *WordBegin = Begin;
41 
42   while (true) {
43     ++Begin;
44 
45     if (Begin == End || isWhitespace(*Begin))
46       return StringRef(WordBegin, Begin - WordBegin);
47   }
48 }
49 
50 // This is the StringSwitch-alike used by lexOrCompleteWord below. See that
51 // function for details.
52 template <typename T> struct QueryParser::LexOrCompleteWord {
53   StringSwitch<T> Switch;
54 
55   QueryParser *P;
56   StringRef Word;
57   // Set to the completion point offset in Word, or StringRef::npos if
58   // completion point not in Word.
59   size_t WordCompletionPos;
60 
61   LexOrCompleteWord(QueryParser *P, StringRef Word, size_t WCP)
62       : Switch(Word), P(P), Word(Word), WordCompletionPos(WCP) {}
63 
64   template <unsigned N>
65   LexOrCompleteWord &Case(const char (&S)[N], const T &Value,
66                           bool IsCompletion = true) {
67     StringRef CaseStr(S, N - 1);
68 
69     if (WordCompletionPos == StringRef::npos)
70       Switch.Case(S, Value);
71     else if (N != 1 && IsCompletion && WordCompletionPos <= CaseStr.size() &&
72              CaseStr.substr(0, WordCompletionPos) ==
73                  Word.substr(0, WordCompletionPos))
74       P->Completions.push_back(LineEditor::Completion(
75           (CaseStr.substr(WordCompletionPos) + " ").str(), CaseStr));
76     return *this;
77   }
78 
79   T Default(const T& Value) const {
80     return Switch.Default(Value);
81   }
82 };
83 
84 // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
85 // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
86 // completions if the lexed word contains the completion point.
87 template <typename T>
88 QueryParser::LexOrCompleteWord<T>
89 QueryParser::lexOrCompleteWord(StringRef &Word) {
90   Word = lexWord();
91   size_t WordCompletionPos = StringRef::npos;
92   if (CompletionPos && CompletionPos <= Word.data() + Word.size()) {
93     if (CompletionPos < Word.data())
94       WordCompletionPos = 0;
95     else
96       WordCompletionPos = CompletionPos - Word.data();
97   }
98   return LexOrCompleteWord<T>(this, Word, WordCompletionPos);
99 }
100 
101 QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
102   StringRef ValStr;
103   unsigned Value = lexOrCompleteWord<unsigned>(ValStr)
104                       .Case("false", 0)
105                       .Case("true", 1)
106                       .Default(~0u);
107   if (Value == ~0u) {
108     return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
109   }
110   return new SetQuery<bool>(Var, Value);
111 }
112 
113 QueryRef QueryParser::parseSetOutputKind() {
114   StringRef ValStr;
115   unsigned OutKind = lexOrCompleteWord<unsigned>(ValStr)
116                          .Case("diag", OK_Diag)
117                          .Case("print", OK_Print)
118                          .Case("dump", OK_Dump)
119                          .Default(~0u);
120   if (OutKind == ~0u) {
121     return new InvalidQuery("expected 'diag', 'print' or 'dump', got '" +
122                             ValStr + "'");
123   }
124   return new SetQuery<OutputKind>(&QuerySession::OutKind, OutputKind(OutKind));
125 }
126 
127 QueryRef QueryParser::endQuery(QueryRef Q) {
128   const char *Extra = Begin;
129   if (!lexWord().empty())
130     return new InvalidQuery("unexpected extra input: '" +
131                             StringRef(Extra, End - Extra) + "'");
132   return Q;
133 }
134 
135 enum ParsedQueryKind {
136   PQK_Invalid,
137   PQK_NoOp,
138   PQK_Help,
139   PQK_Match,
140   PQK_Set
141 };
142 
143 enum ParsedQueryVariable {
144   PQV_Invalid,
145   PQV_Output,
146   PQV_BindRoot
147 };
148 
149 QueryRef QueryParser::doParse() {
150   StringRef CommandStr;
151   ParsedQueryKind QKind = lexOrCompleteWord<ParsedQueryKind>(CommandStr)
152                               .Case("", PQK_NoOp)
153                               .Case("help", PQK_Help)
154                               .Case("m", PQK_Match, /*IsCompletion=*/false)
155                               .Case("match", PQK_Match)
156                               .Case("set", PQK_Set)
157                               .Default(PQK_Invalid);
158 
159   switch (QKind) {
160   case PQK_NoOp:
161     return new NoOpQuery;
162 
163   case PQK_Help:
164     return endQuery(new HelpQuery);
165 
166   case PQK_Match: {
167     if (CompletionPos) {
168       std::vector<MatcherCompletion> Comps = Parser::completeExpression(
169           StringRef(Begin, End - Begin), CompletionPos - Begin);
170       for (std::vector<MatcherCompletion>::iterator I = Comps.begin(),
171                                                     E = Comps.end();
172            I != E; ++I) {
173         Completions.push_back(
174             LineEditor::Completion(I->TypedText, I->MatcherDecl));
175       }
176       return QueryRef();
177     } else {
178       Diagnostics Diag;
179       Optional<DynTypedMatcher> Matcher =
180           Parser::parseMatcherExpression(StringRef(Begin, End - Begin), &Diag);
181       if (!Matcher) {
182         std::string ErrStr;
183         llvm::raw_string_ostream OS(ErrStr);
184         Diag.printToStreamFull(OS);
185         return new InvalidQuery(OS.str());
186       }
187       return new MatchQuery(*Matcher);
188     }
189   }
190 
191   case PQK_Set: {
192     StringRef VarStr;
193     ParsedQueryVariable Var = lexOrCompleteWord<ParsedQueryVariable>(VarStr)
194                                   .Case("output", PQV_Output)
195                                   .Case("bind-root", PQV_BindRoot)
196                                   .Default(PQV_Invalid);
197     if (VarStr.empty())
198       return new InvalidQuery("expected variable name");
199     if (Var == PQV_Invalid)
200       return new InvalidQuery("unknown variable: '" + VarStr + "'");
201 
202     QueryRef Q;
203     switch (Var) {
204     case PQV_Output:
205       Q = parseSetOutputKind();
206       break;
207     case PQV_BindRoot:
208       Q = parseSetBool(&QuerySession::BindRoot);
209       break;
210     case PQV_Invalid:
211       llvm_unreachable("Invalid query kind");
212     }
213 
214     return endQuery(Q);
215   }
216 
217   case PQK_Invalid:
218     return new InvalidQuery("unknown command: " + CommandStr);
219   }
220 
221   llvm_unreachable("Invalid query kind");
222 }
223 
224 QueryRef QueryParser::parse(StringRef Line) {
225   return QueryParser(Line).doParse();
226 }
227 
228 std::vector<LineEditor::Completion> QueryParser::complete(StringRef Line,
229                                                           size_t Pos) {
230   QueryParser P(Line);
231   P.CompletionPos = Line.data() + Pos;
232 
233   P.doParse();
234   return P.Completions;
235 }
236 
237 } // namespace query
238 } // namespace clang
239