--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang-tools-extra/clang-query/QueryParser.cpp	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,351 @@
+//===---- QueryParser.cpp - clang-query command parser --------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "QueryParser.h"
+#include "Query.h"
+#include "QuerySession.h"
+#include "clang/ASTMatchers/Dynamic/Parser.h"
+#include "clang/Basic/CharInfo.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/StringSwitch.h"
+#include <set>
+
+using namespace llvm;
+using namespace clang::ast_matchers::dynamic;
+
+namespace clang {
+namespace query {
+
+// Lex any amount of whitespace followed by a "word" (any sequence of
+// non-whitespace characters) from the start of region [Begin,End).  If no word
+// is found before End, return StringRef().  Begin is adjusted to exclude the
+// lexed region.
+StringRef QueryParser::lexWord() {
+  Line = Line.drop_while([](char c) {
+    // Don't trim newlines.
+    return StringRef(" \t\v\f\r").contains(c);
+  });
+
+  if (Line.empty())
+    // Even though the Line is empty, it contains a pointer and
+    // a (zero) length. The pointer is used in the LexOrCompleteWord
+    // code completion.
+    return Line;
+
+  StringRef Word;
+  if (Line.front() == '#')
+    Word = Line.substr(0, 1);
+  else
+    Word = Line.take_until(isWhitespace);
+
+  Line = Line.drop_front(Word.size());
+  return Word;
+}
+
+// This is the StringSwitch-alike used by lexOrCompleteWord below. See that
+// function for details.
+template <typename T> struct QueryParser::LexOrCompleteWord {
+  StringRef Word;
+  StringSwitch<T> Switch;
+
+  QueryParser *P;
+  // Set to the completion point offset in Word, or StringRef::npos if
+  // completion point not in Word.
+  size_t WordCompletionPos;
+
+  // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
+  // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
+  // completions if the lexed word contains the completion point.
+  LexOrCompleteWord(QueryParser *P, StringRef &OutWord)
+      : Word(P->lexWord()), Switch(Word), P(P),
+        WordCompletionPos(StringRef::npos) {
+    OutWord = Word;
+    if (P->CompletionPos && P->CompletionPos <= Word.data() + Word.size()) {
+      if (P->CompletionPos < Word.data())
+        WordCompletionPos = 0;
+      else
+        WordCompletionPos = P->CompletionPos - Word.data();
+    }
+  }
+
+  LexOrCompleteWord &Case(llvm::StringLiteral CaseStr, const T &Value,
+                          bool IsCompletion = true) {
+
+    if (WordCompletionPos == StringRef::npos)
+      Switch.Case(CaseStr, Value);
+    else if (CaseStr.size() != 0 && IsCompletion && WordCompletionPos <= CaseStr.size() &&
+             CaseStr.substr(0, WordCompletionPos) ==
+                 Word.substr(0, WordCompletionPos))
+      P->Completions.push_back(LineEditor::Completion(
+          (CaseStr.substr(WordCompletionPos) + " ").str(),
+          std::string(CaseStr)));
+    return *this;
+  }
+
+  T Default(T Value) { return Switch.Default(Value); }
+};
+
+QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
+  StringRef ValStr;
+  unsigned Value = LexOrCompleteWord<unsigned>(this, ValStr)
+                       .Case("false", 0)
+                       .Case("true", 1)
+                       .Default(~0u);
+  if (Value == ~0u) {
+    return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
+  }
+  return new SetQuery<bool>(Var, Value);
+}
+
+template <typename QueryType> QueryRef QueryParser::parseSetOutputKind() {
+  StringRef ValStr;
+  unsigned OutKind = LexOrCompleteWord<unsigned>(this, ValStr)
+                         .Case("diag", OK_Diag)
+                         .Case("print", OK_Print)
+                         .Case("detailed-ast", OK_DetailedAST)
+                         .Case("dump", OK_DetailedAST)
+                         .Default(~0u);
+  if (OutKind == ~0u) {
+    return new InvalidQuery(
+        "expected 'diag', 'print', 'detailed-ast' or 'dump', got '" + ValStr +
+        "'");
+  }
+
+  switch (OutKind) {
+  case OK_DetailedAST:
+    return new QueryType(&QuerySession::DetailedASTOutput);
+  case OK_Diag:
+    return new QueryType(&QuerySession::DiagOutput);
+  case OK_Print:
+    return new QueryType(&QuerySession::PrintOutput);
+  }
+
+  llvm_unreachable("Invalid output kind");
+}
+
+QueryRef QueryParser::endQuery(QueryRef Q) {
+  StringRef Extra = Line;
+  StringRef ExtraTrimmed = Extra.drop_while(
+      [](char c) { return StringRef(" \t\v\f\r").contains(c); });
+
+  if ((!ExtraTrimmed.empty() && ExtraTrimmed[0] == '\n') ||
+      (ExtraTrimmed.size() >= 2 && ExtraTrimmed[0] == '\r' &&
+       ExtraTrimmed[1] == '\n'))
+    Q->RemainingContent = Extra;
+  else {
+    StringRef TrailingWord = lexWord();
+    if (!TrailingWord.empty() && TrailingWord.front() == '#') {
+      Line = Line.drop_until([](char c) { return c == '\n'; });
+      Line = Line.drop_while([](char c) { return c == '\n'; });
+      return endQuery(Q);
+    }
+    if (!TrailingWord.empty()) {
+      return new InvalidQuery("unexpected extra input: '" + Extra + "'");
+    }
+  }
+  return Q;
+}
+
+namespace {
+
+enum ParsedQueryKind {
+  PQK_Invalid,
+  PQK_Comment,
+  PQK_NoOp,
+  PQK_Help,
+  PQK_Let,
+  PQK_Match,
+  PQK_Set,
+  PQK_Unlet,
+  PQK_Quit,
+  PQK_Enable,
+  PQK_Disable
+};
+
+enum ParsedQueryVariable {
+  PQV_Invalid,
+  PQV_Output,
+  PQV_BindRoot,
+  PQV_PrintMatcher
+};
+
+QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
+  std::string ErrStr;
+  llvm::raw_string_ostream OS(ErrStr);
+  Diag.printToStreamFull(OS);
+  return new InvalidQuery(OS.str());
+}
+
+} // namespace
+
+QueryRef QueryParser::completeMatcherExpression() {
+  std::vector<MatcherCompletion> Comps = Parser::completeExpression(
+      Line, CompletionPos - Line.begin(), nullptr, &QS.NamedValues);
+  for (auto I = Comps.begin(), E = Comps.end(); I != E; ++I) {
+    Completions.push_back(LineEditor::Completion(I->TypedText, I->MatcherDecl));
+  }
+  return QueryRef();
+}
+
+QueryRef QueryParser::doParse() {
+  StringRef CommandStr;
+  ParsedQueryKind QKind = LexOrCompleteWord<ParsedQueryKind>(this, CommandStr)
+                              .Case("", PQK_NoOp)
+                              .Case("#", PQK_Comment, /*IsCompletion=*/false)
+                              .Case("help", PQK_Help)
+                              .Case("l", PQK_Let, /*IsCompletion=*/false)
+                              .Case("let", PQK_Let)
+                              .Case("m", PQK_Match, /*IsCompletion=*/false)
+                              .Case("match", PQK_Match)
+                              .Case("q", PQK_Quit,  /*IsCompletion=*/false)
+                              .Case("quit", PQK_Quit)
+                              .Case("set", PQK_Set)
+                              .Case("enable", PQK_Enable)
+                              .Case("disable", PQK_Disable)
+                              .Case("unlet", PQK_Unlet)
+                              .Default(PQK_Invalid);
+
+  switch (QKind) {
+  case PQK_Comment:
+  case PQK_NoOp:
+    Line = Line.drop_until([](char c) { return c == '\n'; });
+    Line = Line.drop_while([](char c) { return c == '\n'; });
+    if (Line.empty())
+      return new NoOpQuery;
+    return doParse();
+
+  case PQK_Help:
+    return endQuery(new HelpQuery);
+
+  case PQK_Quit:
+    return endQuery(new QuitQuery);
+
+  case PQK_Let: {
+    StringRef Name = lexWord();
+
+    if (Name.empty())
+      return new InvalidQuery("expected variable name");
+
+    if (CompletionPos)
+      return completeMatcherExpression();
+
+    Diagnostics Diag;
+    ast_matchers::dynamic::VariantValue Value;
+    if (!Parser::parseExpression(Line, nullptr, &QS.NamedValues, &Value,
+                                 &Diag)) {
+      return makeInvalidQueryFromDiagnostics(Diag);
+    }
+
+    auto *Q = new LetQuery(Name, Value);
+    Q->RemainingContent = Line;
+    return Q;
+  }
+
+  case PQK_Match: {
+    if (CompletionPos)
+      return completeMatcherExpression();
+
+    Diagnostics Diag;
+    auto MatcherSource = Line.ltrim();
+    auto OrigMatcherSource = MatcherSource;
+    Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
+        MatcherSource, nullptr, &QS.NamedValues, &Diag);
+    if (!Matcher) {
+      return makeInvalidQueryFromDiagnostics(Diag);
+    }
+    auto ActualSource = OrigMatcherSource.slice(0, OrigMatcherSource.size() -
+                                                       MatcherSource.size());
+    auto *Q = new MatchQuery(ActualSource, *Matcher);
+    Q->RemainingContent = MatcherSource;
+    return Q;
+  }
+
+  case PQK_Set: {
+    StringRef VarStr;
+    ParsedQueryVariable Var =
+        LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
+            .Case("output", PQV_Output)
+            .Case("bind-root", PQV_BindRoot)
+            .Case("print-matcher", PQV_PrintMatcher)
+            .Default(PQV_Invalid);
+    if (VarStr.empty())
+      return new InvalidQuery("expected variable name");
+    if (Var == PQV_Invalid)
+      return new InvalidQuery("unknown variable: '" + VarStr + "'");
+
+    QueryRef Q;
+    switch (Var) {
+    case PQV_Output:
+      Q = parseSetOutputKind<SetExclusiveOutputQuery>();
+      break;
+    case PQV_BindRoot:
+      Q = parseSetBool(&QuerySession::BindRoot);
+      break;
+    case PQV_PrintMatcher:
+      Q = parseSetBool(&QuerySession::PrintMatcher);
+      break;
+    case PQV_Invalid:
+      llvm_unreachable("Invalid query kind");
+    }
+
+    return endQuery(Q);
+  }
+  case PQK_Enable:
+  case PQK_Disable: {
+    StringRef VarStr;
+    ParsedQueryVariable Var =
+        LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
+            .Case("output", PQV_Output)
+            .Default(PQV_Invalid);
+    if (VarStr.empty())
+      return new InvalidQuery("expected variable name");
+    if (Var == PQV_Invalid)
+      return new InvalidQuery("unknown variable: '" + VarStr + "'");
+
+    QueryRef Q;
+
+    if (QKind == PQK_Enable)
+      Q = parseSetOutputKind<EnableOutputQuery>();
+    else if (QKind == PQK_Disable)
+      Q = parseSetOutputKind<DisableOutputQuery>();
+    else
+      llvm_unreachable("Invalid query kind");
+    return endQuery(Q);
+  }
+
+  case PQK_Unlet: {
+    StringRef Name = lexWord();
+
+    if (Name.empty())
+      return new InvalidQuery("expected variable name");
+
+    return endQuery(new LetQuery(Name, VariantValue()));
+  }
+
+  case PQK_Invalid:
+    return new InvalidQuery("unknown command: " + CommandStr);
+  }
+
+  llvm_unreachable("Invalid query kind");
+}
+
+QueryRef QueryParser::parse(StringRef Line, const QuerySession &QS) {
+  return QueryParser(Line, QS).doParse();
+}
+
+std::vector<LineEditor::Completion>
+QueryParser::complete(StringRef Line, size_t Pos, const QuerySession &QS) {
+  QueryParser P(Line, QS);
+  P.CompletionPos = Line.data() + Pos;
+
+  P.doParse();
+  return P.Completions;
+}
+
+} // namespace query
+} // namespace clang