//===- GtestMatchers.cpp - AST Matchers for Gtest ---------------*- C++ -*-===//

//

// 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

//

//===----------------------------------------------------------------------===//

//

// This file implements several matchers for popular gtest macros. In general,

// AST matchers cannot match calls to macros. However, we can simulate such

// matches if the macro definition has identifiable elements that themselves can

// be matched. In that case, we can match on those elements and then check that

// the match occurs within an expansion of the desired macro. The more uncommon

// the identified elements, the more efficient this process will be.

//

//===----------------------------------------------------------------------===//

#include "clang/ASTMatchers/GtestMatchers.h"

#include "clang/AST/ASTConsumer.h"

#include "clang/AST/ASTContext.h"

#include "clang/AST/RecursiveASTVisitor.h"

#include "clang/ASTMatchers/ASTMatchFinder.h"

#include "llvm/ADT/DenseMap.h"

#include "llvm/ADT/StringMap.h"

#include "llvm/ADT/StringRef.h"

namespace clang {

namespace ast_matchers {

namespace {

enum class MacroType {

  Expect,

  Assert,

  On,

};

} // namespace

static DeclarationMatcher getComparisonDecl(GtestCmp Cmp) {

  switch (Cmp) {

  case GtestCmp::Eq:

    return cxxMethodDecl(hasName("Compare"),

                         ofClass(cxxRecordDecl(isSameOrDerivedFrom(

                             hasName("::testing::internal::EqHelper")))));

  case GtestCmp::Ne:

    return functionDecl(hasName("::testing::internal::CmpHelperNE"));

  case GtestCmp::Ge:

    return functionDecl(hasName("::testing::internal::CmpHelperGE"));

  case GtestCmp::Gt:

    return functionDecl(hasName("::testing::internal::CmpHelperGT"));

  case GtestCmp::Le:

    return functionDecl(hasName("::testing::internal::CmpHelperLE"));

  case GtestCmp::Lt:

    return functionDecl(hasName("::testing::internal::CmpHelperLT"));

  }

  llvm_unreachable("Unhandled GtestCmp enum");

}

static llvm::StringRef getMacroTypeName(MacroType Macro) {

  switch (Macro) {

  case MacroType::Expect:

    return "EXPECT";

  case MacroType::Assert:

    return "ASSERT";

  case MacroType::On:

    return "ON";

  }

  llvm_unreachable("Unhandled MacroType enum");

}

static llvm::StringRef getComparisonTypeName(GtestCmp Cmp) {

  switch (Cmp) {

  case GtestCmp::Eq:

    return "EQ";

  case GtestCmp::Ne:

    return "NE";

  case GtestCmp::Ge:

    return "GE";

  case GtestCmp::Gt:

    return "GT";

  case GtestCmp::Le:

    return "LE";

  case GtestCmp::Lt:

    return "LT";

  }

  llvm_unreachable("Unhandled GtestCmp enum");

}

static std::string getMacroName(MacroType Macro, GtestCmp Cmp) {

  return (getMacroTypeName(Macro) + "_" + getComparisonTypeName(Cmp)).str();

}

static std::string getMacroName(MacroType Macro, llvm::StringRef Operation) {

  return (getMacroTypeName(Macro) + "_" + Operation).str();

}

// Under the hood, ON_CALL is expanded to a call to `InternalDefaultActionSetAt`

// to set a default action spec to the underlying function mocker, while

// EXPECT_CALL is expanded to a call to `InternalExpectedAt` to set a new

// expectation spec.

static llvm::StringRef getSpecSetterName(MacroType Macro) {

  switch (Macro) {

  case MacroType::On:

    return "InternalDefaultActionSetAt";

  case MacroType::Expect:

    return "InternalExpectedAt";

  default:

    llvm_unreachable("Unhandled MacroType enum");

  }

  llvm_unreachable("Unhandled MacroType enum");

}

// In general, AST matchers cannot match calls to macros. However, we can

// simulate such matches if the macro definition has identifiable elements that

// themselves can be matched. In that case, we can match on those elements and

// then check that the match occurs within an expansion of the desired

// macro. The more uncommon the identified elements, the more efficient this

// process will be.

//

// We use this approach to implement the derived matchers gtestAssert and

// gtestExpect.

static internal::BindableMatcher<Stmt>

gtestComparisonInternal(MacroType Macro, GtestCmp Cmp, StatementMatcher Left,

                        StatementMatcher Right) {

  return callExpr(isExpandedFromMacro(getMacroName(Macro, Cmp)),

                  callee(getComparisonDecl(Cmp)), hasArgument(2, Left),

                  hasArgument(3, Right));

}

static internal::BindableMatcher<Stmt>

gtestThatInternal(MacroType Macro, StatementMatcher Actual,

                  StatementMatcher Matcher) {

  return cxxOperatorCallExpr(

      isExpandedFromMacro(getMacroName(Macro, "THAT")),

      hasOverloadedOperatorName("()"), hasArgument(2, Actual),

      hasArgument(

          0, expr(hasType(classTemplateSpecializationDecl(hasName(

                      "::testing::internal::PredicateFormatterFromMatcher"))),

                  ignoringImplicit(

                      callExpr(callee(functionDecl(hasName(

                                   "::testing::internal::"

                                   "MakePredicateFormatterFromMatcher"))),

                               hasArgument(0, ignoringImplicit(Matcher)))))));

}

static internal::BindableMatcher<Stmt>

gtestCallInternal(MacroType Macro, StatementMatcher MockCall, MockArgs Args) {

  // A ON_CALL or EXPECT_CALL macro expands to different AST structures

  // depending on whether the mock method has arguments or not.

  switch (Args) {

  // For example,

  // `ON_CALL(mock, TwoParamMethod)` is expanded to

  // `mock.gmock_TwoArgsMethod(WithoutMatchers(),

  // nullptr).InternalDefaultActionSetAt(...)`.

  // EXPECT_CALL is the same except

  // that it calls `InternalExpectedAt` instead of `InternalDefaultActionSetAt`

  // in the end.

  case MockArgs::None:

    return cxxMemberCallExpr(

        isExpandedFromMacro(getMacroName(Macro, "CALL")),

        callee(functionDecl(hasName(getSpecSetterName(Macro)))),

        onImplicitObjectArgument(ignoringImplicit(MockCall)));

  // For example,

  // `ON_CALL(mock, TwoParamMethod(m1, m2))` is expanded to

  // `mock.gmock_TwoParamMethod(m1,m2)(WithoutMatchers(),

  // nullptr).InternalDefaultActionSetAt(...)`.

  // EXPECT_CALL is the same except that it calls `InternalExpectedAt` instead

  // of `InternalDefaultActionSetAt` in the end.

  case MockArgs::Some:

    return cxxMemberCallExpr(

        isExpandedFromMacro(getMacroName(Macro, "CALL")),

        callee(functionDecl(hasName(getSpecSetterName(Macro)))),

        onImplicitObjectArgument(ignoringImplicit(cxxOperatorCallExpr(

            hasOverloadedOperatorName("()"), argumentCountIs(3),

            hasArgument(0, ignoringImplicit(MockCall))))));

  }

  llvm_unreachable("Unhandled MockArgs enum");

}

static internal::BindableMatcher<Stmt>

gtestCallInternal(MacroType Macro, StatementMatcher MockObject,

                  llvm::StringRef MockMethodName, MockArgs Args) {

  return gtestCallInternal(

      Macro,

      cxxMemberCallExpr(

          onImplicitObjectArgument(MockObject),

          callee(functionDecl(hasName(("gmock_" + MockMethodName).str())))),

      Args);

}

internal::BindableMatcher<Stmt> gtestAssert(GtestCmp Cmp, StatementMatcher Left,

                                            StatementMatcher Right) {

  return gtestComparisonInternal(MacroType::Assert, Cmp, Left, Right);

}

internal::BindableMatcher<Stmt> gtestExpect(GtestCmp Cmp, StatementMatcher Left,

                                            StatementMatcher Right) {

  return gtestComparisonInternal(MacroType::Expect, Cmp, Left, Right);

}

internal::BindableMatcher<Stmt> gtestAssertThat(StatementMatcher Actual,

                                                StatementMatcher Matcher) {

  return gtestThatInternal(MacroType::Assert, Actual, Matcher);

}

internal::BindableMatcher<Stmt> gtestExpectThat(StatementMatcher Actual,

                                                StatementMatcher Matcher) {

  return gtestThatInternal(MacroType::Expect, Actual, Matcher);

}

internal::BindableMatcher<Stmt> gtestOnCall(StatementMatcher MockObject,

                                            llvm::StringRef MockMethodName,

                                            MockArgs Args) {

  return gtestCallInternal(MacroType::On, MockObject, MockMethodName, Args);

}

internal::BindableMatcher<Stmt> gtestOnCall(StatementMatcher MockCall,

                                            MockArgs Args) {

  return gtestCallInternal(MacroType::On, MockCall, Args);

}

internal::BindableMatcher<Stmt> gtestExpectCall(StatementMatcher MockObject,

                                                llvm::StringRef MockMethodName,

                                                MockArgs Args) {

  return gtestCallInternal(MacroType::Expect, MockObject, MockMethodName, Args);

}

internal::BindableMatcher<Stmt> gtestExpectCall(StatementMatcher MockCall,

                                                MockArgs Args) {

  return gtestCallInternal(MacroType::Expect, MockCall, Args);

}

} // end namespace ast_matchers

} // end namespace clang