omtcyf0 updated this revision to Diff 48231.
omtcyf0 added a comment.

Followed some suggestions Richard has kindly given me; fixed the nonsense in 
SourceRanges' extracting code


http://reviews.llvm.org/D17244

Files:
  clang-tidy/readability/BracesAroundStatementsCheck.cpp
  clang-tidy/readability/CMakeLists.txt
  clang-tidy/readability/ReadabilityTidyModule.cpp
  clang-tidy/readability/TernaryOperatorCheck.cpp
  clang-tidy/readability/TernaryOperatorCheck.h
  clang-tidy/utils/LexerUtils.cpp
  clang-tidy/utils/LexerUtils.h
  docs/clang-tidy/checks/list.rst
  docs/clang-tidy/checks/readability-ternary-operator.rst
  test/clang-tidy/readability-ternary-operator.cpp

Index: test/clang-tidy/readability-ternary-operator.cpp
===================================================================
--- /dev/null
+++ test/clang-tidy/readability-ternary-operator.cpp
@@ -0,0 +1,134 @@
+// RUN: %check_clang_tidy %s readability-ternary-operator %t
+
+bool Condition = true;
+int Variable = 0;
+
+void call_me(int value);
+void or_me(int value);
+
+//===----------------------------------------------------------------------===//
+// Section #0: warnings without autofixes
+//===----------------------------------------------------------------------===//
+
+int foo() {
+  // regular expressions
+  if (Condition) {
+    Variable++; // comment
+  } else {
+    Variable--;
+  }
+  // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use ternary operator
+
+  if (Condition) {
+    call_me(0);
+  } else {
+    /* something */or_me(1);
+  }
+  // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use ternary operator
+
+  // autofixing is not currently supported for ReturnStmt's
+  if (Condition) {
+    return 0;
+  } else {
+    return 1;
+  }
+  // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use ternary operator
+
+  if (true || /* whatever */ false) {
+    call_me(0);
+  } else {
+    or_me(/* whoops; */ 0);
+  }
+  // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use ternary operator
+
+  if (Condition) {
+#define BLAH 1
+    Variable++;
+  } else {
+    Variable--;
+  }
+  // CHECK-MESSAGES: :[[@LINE-6]]:3: warning: use ternary operator
+}
+
+//===----------------------------------------------------------------------===//
+// Section #1: warnings with autofixes
+//===----------------------------------------------------------------------===//
+
+void boo() {
+  // regular expressions
+  if (Condition) {
+    Variable++;
+  } else {
+    Variable--;
+  }
+  // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use ternary operator
+  // CHECK-FIXES: (Condition) ? Variable++ : Variable--;
+
+  if (Condition)
+    Variable++;
+  else {
+    Variable--;
+  }
+  // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use ternary operator
+  // CHECK-FIXES: (Condition) ? Variable++ : Variable--;
+
+  if (Condition) {
+    Variable++;
+  } else
+    Variable--;
+  // CHECK-MESSAGES: :[[@LINE-4]]:3: warning: use ternary operator
+  // CHECK-FIXES: (Condition) ? Variable++ : Variable--;
+
+  if (Condition)
+    Variable++;
+  else
+    Variable--;
+  // CHECK-MESSAGES: :[[@LINE-4]]:3: warning: use ternary operator
+  // CHECK-FIXES: (Condition) ? Variable++ : Variable--;
+
+  if (Condition) {
+    call_me(0);
+  } else {
+    or_me(0);
+  }
+  // CHECK-MESSAGES: :[[@LINE-5]]:3: warning: use ternary operator
+  // CHECK-FIXES: (Condition) ? call_me(0) : or_me(0);
+
+  // p00rly f0rm4tt3d c0d3
+  if ( true || false ) {true;} else false;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use ternary operator
+  // CHECK-FIXES: ( true || false ) ?true : false;
+
+  if (true)true;else false;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use ternary operator
+  // CHECK-FIXES: (true) ?true : false;
+
+  if (true){true;}else false;
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use ternary operator
+  // CHECK-FIXES: (true) ?true : false;
+
+  if (true)true;else{false;}
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: use ternary operator
+  // CHECK-FIXES: (true) ?true :false;
+}
+
+//===----------------------------------------------------------------------===//
+// Section #2: no warnings and autofixes
+//===----------------------------------------------------------------------===//
+
+void baz() {
+  if (Condition) {
+    Variable = 0;
+  } else if (!Condition) {
+    Variable = 1;
+  } else {
+    Variable = 2;
+  }
+
+  if (Condition) {
+    Variable++;
+    Variable--;
+  } else {
+    Variable++;
+  }
+}
Index: docs/clang-tidy/checks/readability-ternary-operator.rst
===================================================================
--- /dev/null
+++ docs/clang-tidy/checks/readability-ternary-operator.rst
@@ -0,0 +1,26 @@
+.. title:: clang-tidy - readability-ternary-operator
+
+readability-ternary-operator
+============================
+
+This check suggests using ternary operator in where it's possible to do so.
+A typical case where it might improve readability follows this pattern::
+  if (condition) expression0; else expression1;
+And it gets transformed into::
+  (condition ? expression0 : expression1);
+
+Another situation when ternary operator would be suggested::
+  if (condition) return literal0; else return literal1;
+
+Autofixes
+----------------------------
+
+The autofixes are only suggested when no comments and intermediate preprocessor
+lines would be lost.
+
+Consider the following piece of code::
+  if (condition) /* comment */ expression0; else /* and here */ expression1;
+While trying to modify this into an equal piece of code with ternary operator
+both comments will be lost, therefore there will be no autofix suggested for
+such case. If you want the check to perform an autofix, either reposition or
+remove the comments and intermediate preprocessor lines.
Index: docs/clang-tidy/checks/list.rst
===================================================================
--- docs/clang-tidy/checks/list.rst
+++ docs/clang-tidy/checks/list.rst
@@ -94,4 +94,5 @@
    readability-redundant-smartptr-get
    readability-redundant-string-cstr
    readability-simplify-boolean-expr
+   readability-ternary-operator
    readability-uniqueptr-delete-release
Index: clang-tidy/utils/LexerUtils.h
===================================================================
--- clang-tidy/utils/LexerUtils.h
+++ clang-tidy/utils/LexerUtils.h
@@ -22,6 +22,9 @@
 Token getPreviousNonCommentToken(const ASTContext &Context,
                                  SourceLocation Location);
 
+tok::TokenKind getTokenKind(SourceLocation Location, const SourceManager &SM,
+                            const ASTContext *Context);
+
 } // namespace lexer_utils
 } // namespace tidy
 } // namespace clang
Index: clang-tidy/utils/LexerUtils.cpp
===================================================================
--- clang-tidy/utils/LexerUtils.cpp
+++ clang-tidy/utils/LexerUtils.cpp
@@ -34,6 +34,18 @@
   return Token;
 }
 
+
+tok::TokenKind getTokenKind(SourceLocation Location, const SourceManager &SM,
+                            const ASTContext *Context) {
+  Token Tok;
+  SourceLocation Beginning =
+      Lexer::GetBeginningOfToken(Location, SM, Context->getLangOpts());
+  const bool Invalid =
+      Lexer::getRawToken(Beginning, Tok, SM, Context->getLangOpts());
+
+  return (Invalid ? tok::NUM_TOKENS : Tok.getKind());
+}
+
 } // namespace lexer_utils
 } // namespace tidy
 } // namespace clang
Index: clang-tidy/readability/TernaryOperatorCheck.h
===================================================================
--- /dev/null
+++ clang-tidy/readability/TernaryOperatorCheck.h
@@ -0,0 +1,64 @@
+//===--- TernaryOperatorCheck.h - clang-tidy---------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_TERNARY_OPERATOR_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_TERNARY_OPERATOR_H
+
+#include "../ClangTidy.h"
+#include <string>
+#include <vector>
+
+namespace clang {
+namespace tidy {
+namespace readability {
+
+/// Check that suggests using ternary operator where it's possible to.
+///
+/// Before:
+///
+/// \code
+///   if (condition) {
+///     expression0;
+///   } else {
+///     expression1;
+///   }
+/// \endcode
+///
+/// After:
+///
+/// \code
+///   (condition ? expression0 : expression1);
+/// \endcode
+///
+/// Note that if no autofix would be suggested if any comments may be lost.
+///
+/// For the user-facing documentation and more examples see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/readability-ternary-operator.html
+class TernaryOperatorCheck : public ClangTidyCheck {
+public:
+  TernaryOperatorCheck(StringRef Name, ClangTidyContext *Context)
+      : ClangTidyCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+  bool matchIf(const IfStmt *IfNode);
+  std::vector<FixItHint> getHints(const IfStmt *IfNode, const Expr *ThenNode,
+                                  const Expr *ElseNode);
+
+  const SourceManager *SM;
+  const LangOptions *Opts;
+  ASTContext *Ctx;
+};
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_TERNARY_OPERATOR_H
Index: clang-tidy/readability/TernaryOperatorCheck.cpp
===================================================================
--- /dev/null
+++ clang-tidy/readability/TernaryOperatorCheck.cpp
@@ -0,0 +1,188 @@
+//===--- TernaryOperatorCheck.cpp - clang-tidy-----------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TernaryOperatorCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "../utils/LexerUtils.h"
+
+#include <vector>
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace readability {
+namespace {
+
+bool hasTokensInside(const std::vector<tok::TokenKind> TokenKinds,
+                     const SourceRange SR, const SourceManager &SM,
+                     const ASTContext *Context) {
+  for (SourceLocation it = SR.getBegin(); it != SR.getEnd();
+       it = it.getLocWithOffset(1)) {
+    tok::TokenKind TokKind = lexer_utils::getTokenKind(it, SM, Context);
+    for (auto Kind : TokenKinds) {
+      if (Kind == TokKind) {
+        return true;
+      }
+    }
+    // Fast-forward current token.
+    // it = Lexer::getLocForEndOfToken(it, 0, SM, Context->getLangOpts());
+  }
+  return false;
+}
+
+SourceLocation getNextTokenLoc(tok::TokenKind TokKind, SourceLocation Loc,
+                               const SourceManager &SM,
+                               const ASTContext *Context, bool After = true) {
+  SourceLocation Result =
+      Lexer::getLocForEndOfToken(Loc, 0, SM, Context->getLangOpts());
+  while (lexer_utils::getTokenKind(Result, SM, Context) != TokKind) {
+    Result = Result.getLocWithOffset(1);
+  }
+  return Result;
+}
+
+SourceLocation getPrevTokenLoc(tok::TokenKind TokKind, SourceLocation Loc,
+                               const SourceManager &SM,
+                               const ASTContext *Context, bool After = true) {
+  SourceLocation Result =
+      Lexer::GetBeginningOfToken(Loc, SM, Context->getLangOpts());
+  while (lexer_utils::getTokenKind(Result, SM, Context) != TokKind) {
+    Result = Result.getLocWithOffset(-1);
+  }
+  return Result;
+}
+
+} // namespace
+
+void TernaryOperatorCheck::registerMatchers(MatchFinder *Finder) {
+  Finder->addMatcher(ifStmt().bind("IfNode"), this);
+}
+
+bool TernaryOperatorCheck::matchIf(const IfStmt *IfNode) {
+  if (IfNode->getElse() == nullptr) {
+    return false;
+  }
+  if (const auto *ElseIfStmt = dyn_cast<IfStmt>(IfNode->getElse())) {
+    if (ElseIfStmt->getElse() != nullptr) {
+      return false;
+    }
+  }
+  for (const auto Parent : Ctx->getParents(*IfNode)) {
+    if (const IfStmt *ParentIf = Parent.get<IfStmt>()) {
+      if (ParentIf->getElse() == IfNode) {
+        return false;
+      }
+    }
+  }
+  if (const auto *ThenNode = dyn_cast<CompoundStmt>(IfNode->getThen())) {
+    if (ThenNode->size() > 1) {
+      return false;
+    }
+  }
+  if (const auto *ElseNode = dyn_cast<CompoundStmt>(IfNode->getElse())) {
+    if (ElseNode->size() > 1) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void TernaryOperatorCheck::check(const MatchFinder::MatchResult &Result) {
+  this->Opts = &Result.Context->getLangOpts();
+  this->SM = Result.SourceManager;
+  this->Ctx = Result.Context;
+
+  const auto *IfNode = Result.Nodes.getNodeAs<IfStmt>("IfNode");
+  if (!matchIf(IfNode)) {
+    return;
+  }
+
+  const auto *ThenNode =
+      (dyn_cast<CompoundStmt>(IfNode->getThen())
+           ? dyn_cast<CompoundStmt>(IfNode->getThen())->body_front()
+           : IfNode->getThen());
+  const auto *ElseNode =
+      (dyn_cast<CompoundStmt>(IfNode->getElse())
+           ? dyn_cast<CompoundStmt>(IfNode->getElse())->body_front()
+           : IfNode->getElse());
+
+  if (ThenNode->getStmtClass() != ElseNode->getStmtClass()) {
+    return;
+  }
+  if (IfNode->getLocStart().isMacroID()) {
+    return;
+  }
+
+  std::vector<FixItHint> Hints;
+  if (dyn_cast<Expr>(ThenNode) &&
+      !hasTokensInside({tok::comment, tok::hash}, IfNode->getSourceRange(), *SM,
+                       Ctx)) {
+    Hints =
+        getHints(IfNode, dyn_cast<Expr>(ThenNode), dyn_cast<Expr>(ElseNode));
+  }
+
+  auto Diagnostic = diag(IfNode->getLocStart(), "use ternary operator");
+  for (auto Hint : Hints) {
+    Diagnostic.AddFixItHint(Hint);
+  }
+}
+
+std::vector<FixItHint> TernaryOperatorCheck::getHints(const IfStmt *IfNode,
+                                                      const Expr *ThenNode,
+                                                      const Expr *ElseNode) {
+  // Having if (condition) { expression0; else { expression1; }
+  //        ^ ^          ^  ^           ^       ^           ^ ^
+  //        1 2          3  4           5       6           7 8
+  //
+  // Transform into: (condition ? expression0 : expression1);
+  // 1. Replace 1-2 range with "("
+  // 2. Replace 3-4 range with " ? "
+  // 3. Replace 5-6 range with " : "
+  // 4. Insert ")" before 7
+  // 5. Remove 7-8 range
+
+  SourceRange NextRange;
+  std::string NextReplacement;
+  std::vector<FixItHint> Hints;
+
+  NextRange = SourceRange(
+      IfNode->getLocStart(),
+      getPrevTokenLoc(tok::l_paren, IfNode->getCond()->getLocStart(), *SM, Ctx)
+          .getLocWithOffset(-1));
+  Hints.push_back(FixItHint::CreateRemoval(NextRange));
+
+  NextRange = SourceRange(
+      getNextTokenLoc(tok::r_paren, IfNode->getCond()->getLocEnd(), *SM, Ctx),
+      ThenNode->getLocStart().getLocWithOffset(-1));
+  NextReplacement = ") ?";
+
+  Hints.push_back(FixItHint::CreateReplacement(NextRange, NextReplacement));
+  NextRange =
+      SourceRange(getNextTokenLoc(tok::semi, ThenNode->getLocEnd(), *SM, Ctx),
+                  ElseNode->getLocStart().getLocWithOffset(-1));
+  NextReplacement = " :";
+  Hints.push_back(FixItHint::CreateReplacement(NextRange, NextReplacement));
+
+  NextRange = SourceRange(
+      getNextTokenLoc(tok::semi, ElseNode->getLocEnd(), *SM, Ctx)
+          .getLocWithOffset(1),
+      (dyn_cast<CompoundStmt>(IfNode->getElse())
+           ? IfNode->getElse()->getLocEnd()
+           : getNextTokenLoc(tok::semi, ElseNode->getLocEnd(), *SM, Ctx)
+                 .getLocWithOffset(1)));
+  Hints.push_back(FixItHint::CreateRemoval(NextRange));
+
+  return Hints;
+}
+
+} // namespace readability
+} // namespace tidy
+} // namespace clang
Index: clang-tidy/readability/ReadabilityTidyModule.cpp
===================================================================
--- clang-tidy/readability/ReadabilityTidyModule.cpp
+++ clang-tidy/readability/ReadabilityTidyModule.cpp
@@ -22,6 +22,7 @@
 #include "RedundantSmartptrGetCheck.h"
 #include "RedundantStringCStrCheck.h"
 #include "SimplifyBooleanExprCheck.h"
+#include "TernaryOperatorCheck.h"
 #include "UniqueptrDeleteReleaseCheck.h"
 
 namespace clang {
@@ -45,6 +46,8 @@
         "readability-implicit-bool-cast");
     CheckFactories.registerCheck<InconsistentDeclarationParameterNameCheck>(
         "readability-inconsistent-declaration-parameter-name");
+    CheckFactories.registerCheck<TernaryOperatorCheck>(
+        "readability-ternary-operator");
     CheckFactories.registerCheck<readability::NamedParameterCheck>(
         "readability-named-parameter");
     CheckFactories.registerCheck<RedundantControlFlowCheck>(
Index: clang-tidy/readability/CMakeLists.txt
===================================================================
--- clang-tidy/readability/CMakeLists.txt
+++ clang-tidy/readability/CMakeLists.txt
@@ -15,6 +15,7 @@
   RedundantStringCStrCheck.cpp
   RedundantSmartptrGetCheck.cpp
   SimplifyBooleanExprCheck.cpp
+  TernaryOperatorCheck.cpp
   UniqueptrDeleteReleaseCheck.cpp
 
   LINK_LIBS
Index: clang-tidy/readability/BracesAroundStatementsCheck.cpp
===================================================================
--- clang-tidy/readability/BracesAroundStatementsCheck.cpp
+++ clang-tidy/readability/BracesAroundStatementsCheck.cpp
@@ -10,30 +10,16 @@
 #include "BracesAroundStatementsCheck.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/ASTMatchers/ASTMatchers.h"
-#include "clang/Lex/Lexer.h"
+#include "../utils/LexerUtils.h"
 
 using namespace clang::ast_matchers;
+using namespace clang::tidy::lexer_utils;
 
 namespace clang {
 namespace tidy {
 namespace readability {
 namespace {
 
-tok::TokenKind getTokenKind(SourceLocation Loc, const SourceManager &SM,
-                            const ASTContext *Context) {
-  Token Tok;
-  SourceLocation Beginning =
-      Lexer::GetBeginningOfToken(Loc, SM, Context->getLangOpts());
-  const bool Invalid =
-      Lexer::getRawToken(Beginning, Tok, SM, Context->getLangOpts());
-  assert(!Invalid && "Expected a valid token.");
-
-  if (Invalid)
-    return tok::NUM_TOKENS;
-
-  return Tok.getKind();
-}
-
 SourceLocation forwardSkipWhitespaceAndComments(SourceLocation Loc,
                                                 const SourceManager &SM,
                                                 const ASTContext *Context) {
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