Added applyAtomicChanges function.

This re-commits r298913.
o See thread http://lists.llvm.org/pipermail/cfe-commits/Week-of-Mon-20170327/189084.html
o Tested with -DLLVM_ENABLE_LOCAL_SUBMODULE_VISIBILITY=0.

Summary: ... which applies a set of `AtomicChange`s on code.

Reviewers: klimek, djasper

Reviewed By: djasper

Subscribers: arphaman, mgorny, chapuni, cfe-commits

Differential Revision: https://reviews.llvm.org/D30777

llvm-svn: 309548

clang/include/clang/Tooling/Refactoring/AtomicChange.h

@@ -16,6 +16,7 @@
 #define LLVM_CLANG_TOOLING_REFACTOR_ATOMICCHANGE_H
 
 #include "clang/Basic/SourceManager.h"
+#include "clang/Format/Format.h"
 #include "clang/Tooling/Core/Replacement.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Error.h"
@@ -129,6 +130,39 @@ class AtomicChange {
   tooling::Replacements Replaces;
 };
 
+// Defines specs for applying changes.
+struct ApplyChangesSpec {
+  // If true, cleans up redundant/erroneous code around changed code with
+  // clang-format's cleanup functionality, e.g. redundant commas around deleted
+  // parameter or empty namespaces introduced by deletions.
+  bool Cleanup = true;
+
+  format::FormatStyle Style = format::getNoStyle();
+
+  // Options for selectively formatting changes with clang-format:
+  // kAll: Format all changed lines.
+  // kNone: Don't format anything.
+  // kViolations: Format lines exceeding the `ColumnLimit` in `Style`.
+  enum FormatOption { kAll, kNone, kViolations };
+
+  FormatOption Format = kNone;
+};
+
+/// \brief Applies all AtomicChanges in \p Changes to the \p Code.
+///
+/// This completely ignores the file path in each change and replaces them with
+/// \p FilePath, i.e. callers are responsible for ensuring all changes are for
+/// the same file.
+///
+/// \returns The changed code if all changes are applied successfully;
+/// otherwise, an llvm::Error carrying llvm::StringError is returned (the Error
+/// message can be converted to string with `llvm::toString()` and the
+/// error_code should be ignored).
+llvm::Expected<std::string>
+applyAtomicChanges(llvm::StringRef FilePath, llvm::StringRef Code,
+                   llvm::ArrayRef<AtomicChange> Changes,
+                   const ApplyChangesSpec &Spec);
+
 } // end namespace tooling
 } // end namespace clang
 

clang/lib/Tooling/Refactoring/AtomicChange.cpp

@@ -83,6 +83,116 @@ template <> struct MappingTraits<clang::tooling::AtomicChange> {
 
 namespace clang {
 namespace tooling {
+namespace {
+
+// Returns true if there is any line that violates \p ColumnLimit in range
+// [Start, End].
+bool violatesColumnLimit(llvm::StringRef Code, unsigned ColumnLimit,
+                         unsigned Start, unsigned End) {
+  auto StartPos = Code.rfind('\n', Start);
+  StartPos = (StartPos == llvm::StringRef::npos) ? 0 : StartPos + 1;
+
+  auto EndPos = Code.find("\n", End);
+  if (EndPos == llvm::StringRef::npos)
+    EndPos = Code.size();
+
+  llvm::SmallVector<llvm::StringRef, 8> Lines;
+  Code.substr(StartPos, EndPos - StartPos).split(Lines, '\n');
+  for (llvm::StringRef Line : Lines)
+    if (Line.size() > ColumnLimit)
+      return true;
+  return false;
+}
+
+std::vector<Range>
+getRangesForFormating(llvm::StringRef Code, unsigned ColumnLimit,
+                      ApplyChangesSpec::FormatOption Format,
+                      const clang::tooling::Replacements &Replaces) {
+  // kNone suppresses formatting entirely.
+  if (Format == ApplyChangesSpec::kNone)
+    return {};
+  std::vector<clang::tooling::Range> Ranges;
+  // This works assuming that replacements are ordered by offset.
+  // FIXME: use `getAffectedRanges()` to calculate when it does not include '\n'
+  // at the end of an insertion in affected ranges.
+  int Offset = 0;
+  for (const clang::tooling::Replacement &R : Replaces) {
+    int Start = R.getOffset() + Offset;
+    int End = Start + R.getReplacementText().size();
+    if (!R.getReplacementText().empty() &&
+        R.getReplacementText().back() == '\n' && R.getLength() == 0 &&
+        R.getOffset() > 0 && R.getOffset() <= Code.size() &&
+        Code[R.getOffset() - 1] == '\n')
+      // If we are inserting at the start of a line and the replacement ends in
+      // a newline, we don't need to format the subsequent line.
+      --End;
+    Offset += R.getReplacementText().size() - R.getLength();
+
+    if (Format == ApplyChangesSpec::kAll ||
+        violatesColumnLimit(Code, ColumnLimit, Start, End))
+      Ranges.emplace_back(Start, End - Start);
+  }
+  return Ranges;
+}
+
+inline llvm::Error make_string_error(const llvm::Twine &Message) {
+  return llvm::make_error<llvm::StringError>(Message,
+                                             llvm::inconvertibleErrorCode());
+}
+
+// Creates replacements for inserting/deleting #include headers.
+llvm::Expected<Replacements>
+createReplacementsForHeaders(llvm::StringRef FilePath, llvm::StringRef Code,
+                             llvm::ArrayRef<AtomicChange> Changes,
+                             const format::FormatStyle &Style) {
+  // Create header insertion/deletion replacements to be cleaned up
+  // (i.e. converted to real insertion/deletion replacements).
+  Replacements HeaderReplacements;
+  for (const auto &Change : Changes) {
+    for (llvm::StringRef Header : Change.getInsertedHeaders()) {
+      std::string EscapedHeader =
+          Header.startswith("<") || Header.startswith("\"")
+              ? Header.str()
+              : ("\"" + Header + "\"").str();
+      std::string ReplacementText = "#include " + EscapedHeader;
+      // Offset UINT_MAX and length 0 indicate that the replacement is a header
+      // insertion.
+      llvm::Error Err = HeaderReplacements.add(
+          tooling::Replacement(FilePath, UINT_MAX, 0, ReplacementText));
+      if (Err)
+        return std::move(Err);
+    }
+    for (const std::string &Header : Change.getRemovedHeaders()) {
+      // Offset UINT_MAX and length 1 indicate that the replacement is a header
+      // deletion.
+      llvm::Error Err =
+          HeaderReplacements.add(Replacement(FilePath, UINT_MAX, 1, Header));
+      if (Err)
+        return std::move(Err);
+    }
+  }
+
+  // cleanupAroundReplacements() converts header insertions/deletions into
+  // actual replacements that add/remove headers at the right location.
+  return clang::format::cleanupAroundReplacements(Code, HeaderReplacements,
+                                                  Style);
+}
+
+// Combine replacements in all Changes as a `Replacements`. This ignores the
+// file path in all replacements and replaces them with \p FilePath.
+llvm::Expected<Replacements>
+combineReplacementsInChanges(llvm::StringRef FilePath,
+                             llvm::ArrayRef<AtomicChange> Changes) {
+  Replacements Replaces;
+  for (const auto &Change : Changes)
+    for (const auto &R : Change.getReplacements())
+      if (auto Err = Replaces.add(Replacement(
+              FilePath, R.getOffset(), R.getLength(), R.getReplacementText())))
+        return std::move(Err);
+  return Replaces;
+}
+
+} // end namespace
 
 AtomicChange::AtomicChange(const SourceManager &SM,
                            SourceLocation KeyPosition) {
@@ -173,5 +283,74 @@ void AtomicChange::removeHeader(llvm::StringRef Header) {
   RemovedHeaders.push_back(Header);
 }
 
+llvm::Expected<std::string>
+applyAtomicChanges(llvm::StringRef FilePath, llvm::StringRef Code,
+                   llvm::ArrayRef<AtomicChange> Changes,
+                   const ApplyChangesSpec &Spec) {
+  llvm::Expected<Replacements> HeaderReplacements =
+      createReplacementsForHeaders(FilePath, Code, Changes, Spec.Style);
+  if (!HeaderReplacements)
+    return make_string_error(
+        "Failed to create replacements for header changes: " +
+        llvm::toString(HeaderReplacements.takeError()));
+
+  llvm::Expected<Replacements> Replaces =
+      combineReplacementsInChanges(FilePath, Changes);
+  if (!Replaces)
+    return make_string_error("Failed to combine replacements in all changes: " +
+                             llvm::toString(Replaces.takeError()));
+
+  Replacements AllReplaces = std::move(*Replaces);
+  for (const auto &R : *HeaderReplacements) {
+    llvm::Error Err = AllReplaces.add(R);
+    if (Err)
+      return make_string_error(
+          "Failed to combine existing replacements with header replacements: " +
+          llvm::toString(std::move(Err)));
+  }
+
+  if (Spec.Cleanup) {
+    llvm::Expected<Replacements> CleanReplaces =
+        format::cleanupAroundReplacements(Code, AllReplaces, Spec.Style);
+    if (!CleanReplaces)
+      return make_string_error("Failed to cleanup around replacements: " +
+                               llvm::toString(CleanReplaces.takeError()));
+    AllReplaces = std::move(*CleanReplaces);
+  }
+
+  // Apply all replacements.
+  llvm::Expected<std::string> ChangedCode =
+      applyAllReplacements(Code, AllReplaces);
+  if (!ChangedCode)
+    return make_string_error("Failed to apply all replacements: " +
+                             llvm::toString(ChangedCode.takeError()));
+
+  // Sort inserted headers. This is done even if other formatting is turned off
+  // as incorrectly sorted headers are always just wrong, it's not a matter of
+  // taste.
+  Replacements HeaderSortingReplacements = format::sortIncludes(
+      Spec.Style, *ChangedCode, AllReplaces.getAffectedRanges(), FilePath);
+  ChangedCode = applyAllReplacements(*ChangedCode, HeaderSortingReplacements);
+  if (!ChangedCode)
+    return make_string_error(
+        "Failed to apply replacements for sorting includes: " +
+        llvm::toString(ChangedCode.takeError()));
+
+  AllReplaces = AllReplaces.merge(HeaderSortingReplacements);
+
+  std::vector<Range> FormatRanges = getRangesForFormating(
+      *ChangedCode, Spec.Style.ColumnLimit, Spec.Format, AllReplaces);
+  if (!FormatRanges.empty()) {
+    Replacements FormatReplacements =
+        format::reformat(Spec.Style, *ChangedCode, FormatRanges, FilePath);
+    ChangedCode = applyAllReplacements(*ChangedCode, FormatReplacements);
+    if (!ChangedCode)
+      return make_string_error(
+          "Failed to apply replacements for formatting changed code: " +
+          llvm::toString(ChangedCode.takeError()));
+  }
+  return ChangedCode;
+}
+
 } // end namespace tooling
 } // end namespace clang

clang/lib/Tooling/Refactoring/CMakeLists.txt

@@ -1,7 +1,4 @@
-set(LLVM_LINK_COMPONENTS
-  Option
-  Support
-  )
+set(LLVM_LINK_COMPONENTS Support)
 
 add_clang_library(clangToolingRefactor
   AtomicChange.cpp
@@ -14,6 +11,7 @@ add_clang_library(clangToolingRefactor
   clangAST
   clangASTMatchers
   clangBasic
+  clangFormat
   clangIndex
   clangLex
   clangToolingCore