Add functions to apply replacements and reformat them.

This is a commonly useful feature to have, and we have implemented it
multiple times with different kinds of bugs. This implementation
centralizes the idea in a set of functions that we can then use from the various
tools.

Reverts r262234, which is a revert of r262232, and puts the functions
into FOrmat.h, as they are closely coupled to clang-format, and we
otherwise introduce a cyclic dependency between libFormat and
libTooling.

Patch by Eric Liu.

llvm-svn: 262323

7 files changed, 137 insertions, 3 deletions

diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index b32fc3a..f0636ac 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -731,6 +731,28 @@ tooling::Replacements sortIncludes(const FormatStyle &Style, StringRef Code,
                                    StringRef FileName,
                                    unsigned *Cursor = nullptr);
 
+/// \brief Returns the replacements corresponding to applying and formatting
+/// \p Replaces.
+tooling::Replacements formatReplacements(StringRef Code,
+                                         const tooling::Replacements &Replaces,
+                                         const FormatStyle &Style);
+
+/// \brief In addition to applying all replacements in \p Replaces to \p Code,
+/// this function also reformats the changed code after applying replacements.
+///
+/// \pre Replacements must be for the same file and conflict-free.
+///
+/// Replacement applications happen independently of the success of
+/// other applications.
+///
+/// \returns the changed code with all replacements applied and formatted, if
+/// successful. An empty string otherwise.
+///
+/// See also "include/clang/Tooling/Core/Replacements.h".
+std::string applyAllReplacementsAndFormat(StringRef Code,
+                                          const tooling::Replacements &Replaces,
+                                          const FormatStyle &Style);
+
 /// \brief Reformats the given \p Ranges in the file \p ID.
 ///
 /// Each range is extended on either end to its next bigger logic unit, i.e.
diff --git a/clang/include/clang/Tooling/Core/Replacement.h b/clang/include/clang/Tooling/Core/Replacement.h
index 37389ac..4ef7184 100644
--- a/clang/include/clang/Tooling/Core/Replacement.h
+++ b/clang/include/clang/Tooling/Core/Replacement.h
@@ -220,6 +220,13 @@ bool applyAllReplacements(const std::vector<Replacement> &Replaces,
 /// replacements cannot be applied, this returns an empty \c string.
 std::string applyAllReplacements(StringRef Code, const Replacements &Replaces);
 
+/// \brief Calculate the ranges in a single file that are affected by the
+/// Replacements.
+///
+/// \pre Replacements must be for the same file.
+std::vector<tooling::Range>
+calculateChangedRangesInFile(const tooling::Replacements &Replaces);
+
 /// \brief Merges two sets of replacements with the second set referring to the
 /// code after applying the first set. Within both 'First' and 'Second',
 /// replacements must not overlap.
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 85a0152..9d5c0bc 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -1884,6 +1884,34 @@ tooling::Replacements sortIncludes(const FormatStyle &Style, StringRef Code,
   return Replaces;
 }
 
+tooling::Replacements formatReplacements(StringRef Code,
+                                         const tooling::Replacements &Replaces,
+                                         const FormatStyle &Style) {
+  if (Replaces.empty())
+    return tooling::Replacements();
+
+  std::string NewCode = applyAllReplacements(Code, Replaces);
+  std::vector<tooling::Range> ChangedRanges =
+      tooling::calculateChangedRangesInFile(Replaces);
+  StringRef FileName = Replaces.begin()->getFilePath();
+  tooling::Replacements FormatReplaces =
+      reformat(Style, NewCode, ChangedRanges, FileName);
+
+  tooling::Replacements MergedReplacements =
+      mergeReplacements(Replaces, FormatReplaces);
+  return MergedReplacements;
+}
+
+std::string applyAllReplacementsAndFormat(StringRef Code,
+                                          const tooling::Replacements &Replaces,
+                                          const FormatStyle &Style) {
+  tooling::Replacements NewReplacements =
+      formatReplacements(Code, Replaces, Style);
+  if (NewReplacements.empty())
+    return Code; // Exit early to avoid overhead in `applyAllReplacements`.
+  return applyAllReplacements(Code, NewReplacements);
+}
+
 tooling::Replacements reformat(const FormatStyle &Style,
                                SourceManager &SourceMgr, FileID ID,
                                ArrayRef<CharSourceRange> Ranges,
diff --git a/clang/lib/Tooling/Core/Replacement.cpp b/clang/lib/Tooling/Core/Replacement.cpp
index 47bbdeb..6226cf2 100644
--- a/clang/lib/Tooling/Core/Replacement.cpp
+++ b/clang/lib/Tooling/Core/Replacement.cpp
@@ -11,6 +11,8 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "clang/Tooling/Core/Replacement.h"
+
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticIDs.h"
 #include "clang/Basic/DiagnosticOptions.h"
@@ -18,7 +20,6 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Rewrite/Core/Rewriter.h"
-#include "clang/Tooling/Core/Replacement.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/raw_os_ostream.h"
@@ -281,6 +282,18 @@ std::string applyAllReplacements(StringRef Code, const Replacements &Replaces) {
   return Result;
 }
 
+std::vector<Range> calculateChangedRangesInFile(const Replacements &Replaces) {
+  std::vector<Range> ChangedRanges;
+  int Shift = 0;
+  for (const Replacement &R : Replaces) {
+    unsigned Offset = R.getOffset() + Shift;
+    unsigned Length = R.getReplacementText().size();
+    Shift += Length - R.getLength();
+    ChangedRanges.push_back(Range(Offset, Length));
+  }
+  return ChangedRanges;
+}
+
 namespace {
 // Represents a merged replacement, i.e. a replacement consisting of multiple
 // overlapping replacements from 'First' and 'Second' in mergeReplacements.
@@ -314,7 +327,7 @@ public:
 
   // Merges the next element 'R' into this merged element. As we always merge
   // from 'First' into 'Second' or vice versa, the MergedReplacement knows what
-  // set the next element is coming from. 
+  // set the next element is coming from.
   void merge(const Replacement &R) {
     if (MergeSecond) {
       unsigned REnd = R.getOffset() + Delta + R.getLength();
diff --git a/clang/unittests/Format/CMakeLists.txt b/clang/unittests/Format/CMakeLists.txt
index 01af435..de26a47 100644
--- a/clang/unittests/Format/CMakeLists.txt
+++ b/clang/unittests/Format/CMakeLists.txt
@@ -13,5 +13,6 @@ add_clang_unittest(FormatTests
 
 target_link_libraries(FormatTests
   clangFormat
+  clangFrontend
   clangToolingCore
   )
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 164909f..4872565 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -7,8 +7,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "FormatTestUtils.h"
 #include "clang/Format/Format.h"
+
+#include "../Tooling/RewriterTestContext.h"
+#include "FormatTestUtils.h"
+
+#include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "llvm/Support/Debug.h"
 #include "gtest/gtest.h"
 
@@ -11171,6 +11175,46 @@ TEST_F(FormatTest, FormatsTableGenCode) {
   verifyFormat("include \"a.td\"\ninclude \"b.td\"", Style);
 }
 
+class ReplacementTest : public ::testing::Test {
+protected:
+  tooling::Replacement createReplacement(SourceLocation Start, unsigned Length,
+                                         llvm::StringRef ReplacementText) {
+    return tooling::Replacement(Context.Sources, Start, Length,
+                                ReplacementText);
+  }
+
+  RewriterTestContext Context;
+};
+
+TEST_F(ReplacementTest, FormatCodeAfterReplacements) {
+  // Column limit is 20.
+  std::string Code = "Type *a =\n"
+                     "    new Type();\n"
+                     "g(iiiii, 0, jjjjj,\n"
+                     "  0, kkkkk, 0, mm);\n"
+                     "int  bad     = format   ;";
+  std::string Expected = "auto a = new Type();\n"
+                         "g(iiiii, nullptr,\n"
+                         "  jjjjj, nullptr,\n"
+                         "  kkkkk, nullptr,\n"
+                         "  mm);\n"
+                         "int  bad     = format   ;";
+  FileID ID = Context.createInMemoryFile("format.cpp", Code);
+  tooling::Replacements Replaces;
+  Replaces.insert(tooling::Replacement(
+      Context.Sources, Context.getLocation(ID, 1, 1), 6, "auto "));
+  Replaces.insert(tooling::Replacement(
+      Context.Sources, Context.getLocation(ID, 3, 10), 1, "nullptr"));
+  Replaces.insert(tooling::Replacement(
+      Context.Sources, Context.getLocation(ID, 4, 3), 1, "nullptr"));
+  Replaces.insert(tooling::Replacement(
+      Context.Sources, Context.getLocation(ID, 4, 13), 1, "nullptr"));
+
+  format::FormatStyle Style = format::getLLVMStyle();
+  Style.ColumnLimit = 20; // Set column limit to 20 to increase readibility.
+  EXPECT_EQ(Expected, applyAllReplacementsAndFormat(Code, Replaces, Style));
+}
+
 } // end namespace
 } // end namespace format
 } // end namespace clang
diff --git a/clang/unittests/Tooling/RefactoringTest.cpp b/clang/unittests/Tooling/RefactoringTest.cpp
index ff11aea..73da5a8 100644
--- a/clang/unittests/Tooling/RefactoringTest.cpp
+++ b/clang/unittests/Tooling/RefactoringTest.cpp
@@ -418,6 +418,25 @@ TEST(Range, contains) {
   EXPECT_FALSE(Range(0, 10).contains(Range(0, 11)));
 }
 
+TEST(Range, CalculateRangesOfReplacements) {
+  // Before: aaaabbbbbbz
+  // After : bbbbbbzzzzzzoooooooooooooooo
+  Replacements Replaces;
+  Replaces.insert(Replacement("foo", 0, 4, ""));
+  Replaces.insert(Replacement("foo", 10, 1, "zzzzzz"));
+  Replaces.insert(Replacement("foo", 11, 0, "oooooooooooooooo"));
+
+  std::vector<Range> Ranges = calculateChangedRangesInFile(Replaces);
+
+  EXPECT_EQ(3ul, Ranges.size());
+  EXPECT_TRUE(Ranges[0].getOffset() == 0);
+  EXPECT_TRUE(Ranges[0].getLength() == 0);
+  EXPECT_TRUE(Ranges[1].getOffset() == 6);
+  EXPECT_TRUE(Ranges[1].getLength() == 6);
+  EXPECT_TRUE(Ranges[2].getOffset() == 12);
+  EXPECT_TRUE(Ranges[2].getLength() == 16);
+}
+
 TEST(DeduplicateTest, removesDuplicates) {
   std::vector<Replacement> Input;
   Input.push_back(Replacement("fileA", 50, 0, " foo "));