Added Fixer implementation and fix() interface in clang-format for removing redundant code.

Summary:
After applying replacements, redundant code like extra commas or empty namespaces
might be introduced. Fixer can detect and remove any redundant code introduced by replacements.
The current implementation only handles redundant commas.

Reviewers: djasper, klimek

Subscribers: ioeric, mprobst, klimek, cfe-commits

Differential Revision: http://reviews.llvm.org/D18551

llvm-svn: 267416

1 files changed, 150 insertions, 0 deletions

diff --git a/clang/lib/Format/AffectedRangeManager.cpp b/clang/lib/Format/AffectedRangeManager.cpp
new file mode 100644
index 0000000..5d4df19
--- /dev/null
+++ b/clang/lib/Format/AffectedRangeManager.cpp
@@ -0,0 +1,150 @@
+//===--- AffectedRangeManager.cpp - Format C++ code -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file implements AffectRangeManager class.
+///
+//===----------------------------------------------------------------------===//
+
+#include "AffectedRangeManager.h"
+
+#include "FormatToken.h"
+#include "TokenAnnotator.h"
+
+namespace clang {
+namespace format {
+
+bool AffectedRangeManager::computeAffectedLines(
+    SmallVectorImpl<AnnotatedLine *>::iterator I,
+    SmallVectorImpl<AnnotatedLine *>::iterator E) {
+  bool SomeLineAffected = false;
+  const AnnotatedLine *PreviousLine = nullptr;
+  while (I != E) {
+    AnnotatedLine *Line = *I;
+    Line->LeadingEmptyLinesAffected = affectsLeadingEmptyLines(*Line->First);
+
+    // If a line is part of a preprocessor directive, it needs to be formatted
+    // if any token within the directive is affected.
+    if (Line->InPPDirective) {
+      FormatToken *Last = Line->Last;
+      SmallVectorImpl<AnnotatedLine *>::iterator PPEnd = I + 1;
+      while (PPEnd != E && !(*PPEnd)->First->HasUnescapedNewline) {
+        Last = (*PPEnd)->Last;
+        ++PPEnd;
+      }
+
+      if (affectsTokenRange(*Line->First, *Last,
+                            /*IncludeLeadingNewlines=*/false)) {
+        SomeLineAffected = true;
+        markAllAsAffected(I, PPEnd);
+      }
+      I = PPEnd;
+      continue;
+    }
+
+    if (nonPPLineAffected(Line, PreviousLine))
+      SomeLineAffected = true;
+
+    PreviousLine = Line;
+    ++I;
+  }
+  return SomeLineAffected;
+}
+
+bool AffectedRangeManager::affectsCharSourceRange(
+    const CharSourceRange &Range) {
+  for (SmallVectorImpl<CharSourceRange>::const_iterator I = Ranges.begin(),
+                                                        E = Ranges.end();
+       I != E; ++I) {
+    if (!SourceMgr.isBeforeInTranslationUnit(Range.getEnd(), I->getBegin()) &&
+        !SourceMgr.isBeforeInTranslationUnit(I->getEnd(), Range.getBegin()))
+      return true;
+  }
+  return false;
+}
+
+bool AffectedRangeManager::affectsTokenRange(const FormatToken &First,
+                                             const FormatToken &Last,
+                                             bool IncludeLeadingNewlines) {
+  SourceLocation Start = First.WhitespaceRange.getBegin();
+  if (!IncludeLeadingNewlines)
+    Start = Start.getLocWithOffset(First.LastNewlineOffset);
+  SourceLocation End = Last.getStartOfNonWhitespace();
+  End = End.getLocWithOffset(Last.TokenText.size());
+  CharSourceRange Range = CharSourceRange::getCharRange(Start, End);
+  return affectsCharSourceRange(Range);
+}
+
+bool AffectedRangeManager::affectsLeadingEmptyLines(const FormatToken &Tok) {
+  CharSourceRange EmptyLineRange = CharSourceRange::getCharRange(
+      Tok.WhitespaceRange.getBegin(),
+      Tok.WhitespaceRange.getBegin().getLocWithOffset(Tok.LastNewlineOffset));
+  return affectsCharSourceRange(EmptyLineRange);
+}
+
+void AffectedRangeManager::markAllAsAffected(
+    SmallVectorImpl<AnnotatedLine *>::iterator I,
+    SmallVectorImpl<AnnotatedLine *>::iterator E) {
+  while (I != E) {
+    (*I)->Affected = true;
+    markAllAsAffected((*I)->Children.begin(), (*I)->Children.end());
+    ++I;
+  }
+}
+
+bool AffectedRangeManager::nonPPLineAffected(
+    AnnotatedLine *Line, const AnnotatedLine *PreviousLine) {
+  bool SomeLineAffected = false;
+  Line->ChildrenAffected =
+      computeAffectedLines(Line->Children.begin(), Line->Children.end());
+  if (Line->ChildrenAffected)
+    SomeLineAffected = true;
+
+  // Stores whether one of the line's tokens is directly affected.
+  bool SomeTokenAffected = false;
+  // Stores whether we need to look at the leading newlines of the next token
+  // in order to determine whether it was affected.
+  bool IncludeLeadingNewlines = false;
+
+  // Stores whether the first child line of any of this line's tokens is
+  // affected.
+  bool SomeFirstChildAffected = false;
+
+  for (FormatToken *Tok = Line->First; Tok; Tok = Tok->Next) {
+    // Determine whether 'Tok' was affected.
+    if (affectsTokenRange(*Tok, *Tok, IncludeLeadingNewlines))
+      SomeTokenAffected = true;
+
+    // Determine whether the first child of 'Tok' was affected.
+    if (!Tok->Children.empty() && Tok->Children.front()->Affected)
+      SomeFirstChildAffected = true;
+
+    IncludeLeadingNewlines = Tok->Children.empty();
+  }
+
+  // Was this line moved, i.e. has it previously been on the same line as an
+  // affected line?
+  bool LineMoved = PreviousLine && PreviousLine->Affected &&
+                   Line->First->NewlinesBefore == 0;
+
+  bool IsContinuedComment =
+      Line->First->is(tok::comment) && Line->First->Next == nullptr &&
+      Line->First->NewlinesBefore < 2 && PreviousLine &&
+      PreviousLine->Affected && PreviousLine->Last->is(tok::comment);
+
+  if (SomeTokenAffected || SomeFirstChildAffected || LineMoved ||
+      IsContinuedComment) {
+    Line->Affected = true;
+    SomeLineAffected = true;
+  }
+  return SomeLineAffected;
+}
+
+} // namespace format
+} // namespace clang