[libclang] Expose Rewriter in libclang API

[arphaman]

I think the methods that use the rewriter should be prefixed with clang_Rewriter_ to match the naming convention, e.g. clang_Rewriter_removeText, clang_Rewriter_dispose, clang_Rewriter_create.

Can you add a libclang unit test for the rewriter?

[jkorous]

• added tests
• renamed with prefix

[arphaman]

LGTM, with one comment below:

clang/include/clang-c/Rewrite.h

21

That should be prefixed with CX to be CXRewriter to match the naming convention.

clang/include/clang-c/Rewrite.h

+/*===-- clang-c/Rewrite.h - C CXRewriter   --------------------------*- 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                    *|
+|*                                                                            *|
+|*===----------------------------------------------------------------------===*/
+
+#ifndef LLVM_CLANG_C_REWRITE_H
+#define LLVM_CLANG_C_REWRITE_H
+
+#include "clang-c/CXString.h"
+#include "clang-c/ExternC.h"
+#include "clang-c/Index.h"
+#include "clang-c/Platform.h"
+
+LLVM_CLANG_C_EXTERN_C_BEGIN
+
+typedef void *CXRewriter;
+
+/**
+ * Create CXRewriter.
+ */
+CINDEX_LINKAGE CXRewriter clang_CXRewriter_create(CXTranslationUnit TU);
+
+/**
+ * Insert the specified string at the specified location in the original buffer.
+ */
+CINDEX_LINKAGE void clang_CXRewriter_insertTextBefore(CXRewriter Rew, CXSourceLocation Loc,
+                                           const char *Insert);
+
+/**
+ * Replace the specified range of characters in the input with the specified
+ * replacement.
+ */
+CINDEX_LINKAGE void clang_CXRewriter_replaceText(CXRewriter Rew, CXSourceRange ToBeReplaced,
+                                      const char *Replacement);
+
+/**
+ * Remove the specified range.
+ */
+CINDEX_LINKAGE void clang_CXRewriter_removeText(CXRewriter Rew, CXSourceRange ToBeRemoved);
+
+/**
+ * Save all changed files to disk.
+ * Returns 1 if any files were not saved successfully, returns 0 otherwise.
+ */
+CINDEX_LINKAGE int clang_CXRewriter_overwriteChangedFiles(CXRewriter Rew);
+
+/**
+ * Write out rewritten version of the main file to stdout.
+ */
+CINDEX_LINKAGE void clang_CXRewriter_writeMainFileToStdOut(CXRewriter Rew);
+
+/**
+ * Free the given CXRewriter.
+ */
+CINDEX_LINKAGE void clang_CXRewriter_dispose(CXRewriter Rew);
+
+LLVM_CLANG_C_EXTERN_C_END
+
+#endif

clang/tools/libclang/CMakeLists.txt

set(SOURCES
   CXCompilationDatabase.cpp
   CXLoadedDiagnostic.cpp
   CXSourceLocation.cpp
   CXStoredDiagnostic.cpp
   CXString.cpp
   CXType.cpp
   Indexing.cpp
   FatalErrorHandler.cpp
+  Rewrite.cpp
 
   ADDITIONAL_HEADERS
   CIndexDiagnostic.h
   CIndexer.h
   CXCursor.h
   CXLoadedDiagnostic.h
   CXSourceLocation.h
   CXString.h

clang/tools/libclang/Rewrite.cpp

+//===- Rewrite.cpp --------------------------------------------------------===//
+//
+// 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 "clang-c/Rewrite.h"
+#include "CXSourceLocation.h"
+#include "CXTranslationUnit.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Frontend/ASTUnit.h"
+#include "clang/Rewrite/Core/Rewriter.h"
+
+CXRewriter clang_CXRewriter_create(CXTranslationUnit TU) {
+  if (clang::cxtu::isNotUsableTU(TU)) {
+    LOG_BAD_TU(TU);
+    return {};
+  }
+  clang::ASTUnit *AU = clang::cxtu::getASTUnit(TU);
+  assert(AU);
+  return reinterpret_cast<CXRewriter>(
+      new clang::Rewriter(AU->getSourceManager(), AU->getLangOpts()));
+}
+
+void clang_CXRewriter_insertTextBefore(CXRewriter Rew, CXSourceLocation Loc,
+                            const char *Insert) {
+  assert(Rew);
+  clang::Rewriter &R = *reinterpret_cast<clang::Rewriter *>(Rew);
+  R.InsertTextBefore(clang::cxloc::translateSourceLocation(Loc), Insert);
+}
+
+void clang_CXRewriter_replaceText(CXRewriter Rew, CXSourceRange ToBeReplaced,
+                       const char *Replacement) {
+  assert(Rew);
+  clang::Rewriter &R = *reinterpret_cast<clang::Rewriter *>(Rew);
+  R.ReplaceText(clang::cxloc::translateCXRangeToCharRange(ToBeReplaced),
+                Replacement);
+}
+
+void clang_CXRewriter_removeText(CXRewriter Rew, CXSourceRange ToBeRemoved) {
+  assert(Rew);
+  clang::Rewriter &R = *reinterpret_cast<clang::Rewriter *>(Rew);
+  R.RemoveText(clang::cxloc::translateCXRangeToCharRange(ToBeRemoved));
+}
+
+int clang_CXRewriter_overwriteChangedFiles(CXRewriter Rew) {
+  assert(Rew);
+  clang::Rewriter &R = *reinterpret_cast<clang::Rewriter *>(Rew);
+  return R.overwriteChangedFiles();
+}
+
+void clang_CXRewriter_writeMainFileToStdOut(CXRewriter Rew) {
+  assert(Rew);
+  clang::Rewriter &R = *reinterpret_cast<clang::Rewriter *>(Rew);
+  R.getEditBuffer(R.getSourceMgr().getMainFileID()).write(llvm::outs());
+}
+
+void clang_CXRewriter_dispose(CXRewriter Rew) {
+  if (Rew)
+    delete reinterpret_cast<clang::Rewriter *>(Rew);
+}

clang/tools/libclang/libclang.exports

 clang_PrintingPolicy_getProperty
 clang_PrintingPolicy_setProperty
 clang_PrintingPolicy_dispose
 clang_install_aborting_llvm_fatal_error_handler
 clang_uninstall_llvm_fatal_error_handler
 clang_Cursor_getVarDeclInitializer
 clang_Cursor_hasVarDeclGlobalStorage
 clang_Cursor_hasVarDeclExternalStorage
+clang_CXRewriter_create
+clang_CXRewriter_insertTextBefore
+clang_CXRewriter_replaceText
+clang_CXRewriter_removeText
+clang_CXRewriter_overwriteChangedFiles
+clang_CXRewriter_writeMainFileToStdOut
+clang_CXRewriter_dispose

clang/unittests/libclang/LibclangTest.cpp

 //===- unittests/libclang/LibclangTest.cpp --- libclang tests -------------===//
 //
 // 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 "clang-c/Index.h"
+#include "clang-c/Rewrite.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_ostream.h"
 #include "gtest/gtest.h"
 #include "TestUtils.h"
 #include <fstream>
clang_visitChildren(
         if (clang_getCursorKind(cursor) == CXCursor_VarDecl) {
           EXPECT_TRUE(clang_Cursor_hasVarDeclExternalStorage(cursor));
           return CXChildVisit_Break;
         }
         return CXChildVisit_Continue;
       },
       nullptr);
 }
+class LibclangRewriteTest : public LibclangParseTest {
+public:
+  CXRewriter Rew = nullptr;
+  std::string Filename;
+  CXFile File = nullptr;
+
+  void SetUp() override {
+    LibclangParseTest::SetUp();
+    Filename = "file.cpp";
+    WriteFile(Filename, "int main() { return 0; }");
+    ClangTU = clang_parseTranslationUnit(Index, Filename.c_str(), nullptr, 0,
+                                         nullptr, 0, TUFlags);
+    Rew = clang_CXRewriter_create(ClangTU);
+    File = clang_getFile(ClangTU, Filename.c_str());
+  }
+  void TearDown() override {
+    clang_CXRewriter_dispose(Rew);
+    LibclangParseTest::TearDown();
+  }
+};
+
+static std::string getFileContent(const std::string& Filename) {
+  std::ifstream RewrittenFile(Filename);
+  std::string RewrittenFileContent;
+  std::string Line;
+  while (std::getline(RewrittenFile, Line)) {
+    if (RewrittenFileContent.empty())
+      RewrittenFileContent = Line;
+    else {
+      RewrittenFileContent += "\n" + Line;
+    }
+  }
+  return RewrittenFileContent;
+}
+
+TEST_F(LibclangRewriteTest, RewriteReplace) {
+  CXSourceLocation B = clang_getLocation(ClangTU, File, 1, 5);
+  CXSourceLocation E = clang_getLocation(ClangTU, File, 1, 9);
+  CXSourceRange Rng = clang_getRange(B, E);
+
+  clang_CXRewriter_replaceText(Rew, Rng, "MAIN");
+
+  ASSERT_EQ(clang_CXRewriter_overwriteChangedFiles(Rew), 0);
+  EXPECT_EQ(getFileContent(Filename), "int MAIN() { return 0; }");
+}
+
+TEST_F(LibclangRewriteTest, RewriteReplaceShorter) {
+  CXSourceLocation B = clang_getLocation(ClangTU, File, 1, 5);
+  CXSourceLocation E = clang_getLocation(ClangTU, File, 1, 9);
+  CXSourceRange Rng = clang_getRange(B, E);
+
+  clang_CXRewriter_replaceText(Rew, Rng, "foo");
+
+  ASSERT_EQ(clang_CXRewriter_overwriteChangedFiles(Rew), 0);
+  EXPECT_EQ(getFileContent(Filename), "int foo() { return 0; }");
+}
+
+TEST_F(LibclangRewriteTest, RewriteReplaceLonger) {
+  CXSourceLocation B = clang_getLocation(ClangTU, File, 1, 5);
+  CXSourceLocation E = clang_getLocation(ClangTU, File, 1, 9);
+  CXSourceRange Rng = clang_getRange(B, E);
+
+  clang_CXRewriter_replaceText(Rew, Rng, "patatino");
+
+  ASSERT_EQ(clang_CXRewriter_overwriteChangedFiles(Rew), 0);
+  EXPECT_EQ(getFileContent(Filename), "int patatino() { return 0; }");
+}
+
+TEST_F(LibclangRewriteTest, RewriteInsert) {
+  CXSourceLocation Loc = clang_getLocation(ClangTU, File, 1, 5);
+
+  clang_CXRewriter_insertTextBefore(Rew, Loc, "ro");
+
+  ASSERT_EQ(clang_CXRewriter_overwriteChangedFiles(Rew), 0);
+  EXPECT_EQ(getFileContent(Filename), "int romain() { return 0; }");
+}
+
+TEST_F(LibclangRewriteTest, RewriteRemove) {
+  CXSourceLocation B = clang_getLocation(ClangTU, File, 1, 5);
+  CXSourceLocation E = clang_getLocation(ClangTU, File, 1, 9);
+  CXSourceRange Rng = clang_getRange(B, E);
+
+  clang_CXRewriter_removeText(Rew, Rng);
+
+  ASSERT_EQ(clang_CXRewriter_overwriteChangedFiles(Rew), 0);
+  EXPECT_EQ(getFileContent(Filename), "int () { return 0; }");
+}