1 files changed, 153 insertions, 0 deletions
diff --git a/clang/lib/AST/CommentBriefParser.cpp b/clang/lib/AST/CommentBriefParser.cpp
new file mode 100644
index 000000000000..2b648cbb1d4b
--- /dev/null
+++ b/clang/lib/AST/CommentBriefParser.cpp
@@ -0,0 +1,153 @@
+//===--- CommentBriefParser.cpp - Dumb comment parser ---------------------===//
+//
+// 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/AST/CommentBriefParser.h"
+#include "clang/AST/CommentCommandTraits.h"
+
+namespace clang {
+namespace comments {
+
+namespace {
+inline bool isWhitespace(char C) {
+  return C == ' ' || C == '\n' || C == '\r' ||
+         C == '\t' || C == '\f' || C == '\v';
+}
+
+/// Convert all whitespace into spaces, remove leading and trailing spaces,
+/// compress multiple spaces into one.
+void cleanupBrief(std::string &S) {
+  bool PrevWasSpace = true;
+  std::string::iterator O = S.begin();
+  for (std::string::iterator I = S.begin(), E = S.end();
+       I != E; ++I) {
+    const char C = *I;
+    if (isWhitespace(C)) {
+      if (!PrevWasSpace) {
+        *O++ = ' ';
+        PrevWasSpace = true;
+      }
+      continue;
+    } else {
+      *O++ = C;
+      PrevWasSpace = false;
+    }
+  }
+  if (O != S.begin() && *(O - 1) == ' ')
+    --O;
+
+  S.resize(O - S.begin());
+}
+
+bool isWhitespace(StringRef Text) {
+  for (StringRef::const_iterator I = Text.begin(), E = Text.end();
+       I != E; ++I) {
+    if (!isWhitespace(*I))
+      return false;
+  }
+  return true;
+}
+} // unnamed namespace
+
+BriefParser::BriefParser(Lexer &L, const CommandTraits &Traits) :
+    L(L), Traits(Traits) {
+  // Get lookahead token.
+  ConsumeToken();
+}
+
+std::string BriefParser::Parse() {
+  std::string FirstParagraphOrBrief;
+  std::string ReturnsParagraph;
+  bool InFirstParagraph = true;
+  bool InBrief = false;
+  bool InReturns = false;
+
+  while (Tok.isNot(tok::eof)) {
+    if (Tok.is(tok::text)) {
+      if (InFirstParagraph || InBrief)
+        FirstParagraphOrBrief += Tok.getText();
+      else if (InReturns)
+        ReturnsParagraph += Tok.getText();
+      ConsumeToken();
+      continue;
+    }
+
+    if (Tok.is(tok::backslash_command) || Tok.is(tok::at_command)) {
+      const CommandInfo *Info = Traits.getCommandInfo(Tok.getCommandID());
+      if (Info->IsBriefCommand) {
+        FirstParagraphOrBrief.clear();
+        InBrief = true;
+        ConsumeToken();
+        continue;
+      }
+      if (Info->IsReturnsCommand) {
+        InReturns = true;
+        InBrief = false;
+        InFirstParagraph = false;
+        ReturnsParagraph += "Returns ";
+        ConsumeToken();
+        continue;
+      }
+      // Block commands implicitly start a new paragraph.
+      if (Info->IsBlockCommand) {
+        // We found an implicit paragraph end.
+        InFirstParagraph = false;
+        if (InBrief)
+          break;
+      }
+    }
+
+    if (Tok.is(tok::newline)) {
+      if (InFirstParagraph || InBrief)
+        FirstParagraphOrBrief += ' ';
+      else if (InReturns)
+        ReturnsParagraph += ' ';
+      ConsumeToken();
+
+      // If the next token is a whitespace only text, ignore it.  Thus we allow
+      // two paragraphs to be separated by line that has only whitespace in it.
+      //
+      // We don't need to add a space to the parsed text because we just added
+      // a space for the newline.
+      if (Tok.is(tok::text)) {
+        if (isWhitespace(Tok.getText()))
+          ConsumeToken();
+      }
+
+      if (Tok.is(tok::newline)) {
+        ConsumeToken();
+        // We found a paragraph end.  This ends the brief description if
+        // \command or its equivalent was explicitly used.
+        // Stop scanning text because an explicit \paragraph is the
+        // preffered one.
+        if (InBrief)
+          break;
+        // End first paragraph if we found some non-whitespace text.
+        if (InFirstParagraph && !isWhitespace(FirstParagraphOrBrief))
+          InFirstParagraph = false;
+        // End the \\returns paragraph because we found the paragraph end.
+        InReturns = false;
+      }
+      continue;
+    }
+
+    // We didn't handle this token, so just drop it.
+    ConsumeToken();
+  }
+
+  cleanupBrief(FirstParagraphOrBrief);
+  if (!FirstParagraphOrBrief.empty())
+    return FirstParagraphOrBrief;
+
+  cleanupBrief(ReturnsParagraph);
+  return ReturnsParagraph;
+}
+
+} // end namespace comments
+} // end namespace clang
+
+