+// From the given position, find the next character after the word.
+static size_t SkipWord(StringRef Str, size_t Loc) {
+ while (Loc < Str.size() && IsPartOfWord(Str[Loc]))
+ ++Loc;
+ return Loc;
+}
+
+// Try to find the first match in buffer for any prefix. If a valid match is
+// found, return that prefix and set its type and location. If there are almost
+// matches (e.g. the actual prefix string is found, but is not an actual check
+// string), but no valid match, return an empty string and set the position to
+// resume searching from. If no partial matches are found, return an empty
+// string and the location will be StringRef::npos. If one prefix is a substring
+// of another, the maximal match should be found. e.g. if "A" and "AA" are
+// prefixes then AA-CHECK: should match the second one.
+static StringRef FindFirstCandidateMatch(StringRef &Buffer,
+ Check::CheckType &CheckTy,
+ size_t &CheckLoc) {
+ StringRef FirstPrefix;
+ size_t FirstLoc = StringRef::npos;
+ size_t SearchLoc = StringRef::npos;
+ Check::CheckType FirstTy = Check::CheckNone;
+
+ CheckTy = Check::CheckNone;
+ CheckLoc = StringRef::npos;
+
+ for (prefix_iterator I = CheckPrefixes.begin(), E = CheckPrefixes.end();
+ I != E; ++I) {
+ StringRef Prefix(*I);
+ size_t PrefixLoc = Buffer.find(Prefix);
+
+ if (PrefixLoc == StringRef::npos)
+ continue;
+
+ // Track where we are searching for invalid prefixes that look almost right.
+ // We need to only advance to the first partial match on the next attempt
+ // since a partial match could be a substring of a later, valid prefix.
+ // Need to skip to the end of the word, otherwise we could end up
+ // matching a prefix in a substring later.
+ if (PrefixLoc < SearchLoc)
+ SearchLoc = SkipWord(Buffer, PrefixLoc);
+
+ // We only want to find the first match to avoid skipping some.
+ if (PrefixLoc > FirstLoc)
+ continue;
+ // If one matching check-prefix is a prefix of another, choose the
+ // longer one.
+ if (PrefixLoc == FirstLoc && Prefix.size() < FirstPrefix.size())
+ continue;
+
+ StringRef Rest = Buffer.drop_front(PrefixLoc);
+ // Make sure we have actually found the prefix, and not a word containing
+ // it. This should also prevent matching the wrong prefix when one is a
+ // substring of another.
+ if (PrefixLoc != 0 && IsPartOfWord(Buffer[PrefixLoc - 1]))
+ FirstTy = Check::CheckNone;
+ else
+ FirstTy = FindCheckType(Rest, Prefix);
+
+ FirstLoc = PrefixLoc;
+ FirstPrefix = Prefix;
+ }
+
+ // If the first prefix is invalid, we should continue the search after it.
+ if (FirstTy == Check::CheckNone) {
+ CheckLoc = SearchLoc;
+ return "";
+ }
+
+ CheckTy = FirstTy;
+ CheckLoc = FirstLoc;
+ return FirstPrefix;
+}
+
+static StringRef FindFirstMatchingPrefix(StringRef &Buffer,
+ unsigned &LineNumber,
+ Check::CheckType &CheckTy,
+ size_t &CheckLoc) {
+ while (!Buffer.empty()) {
+ StringRef Prefix = FindFirstCandidateMatch(Buffer, CheckTy, CheckLoc);
+ // If we found a real match, we are done.
+ if (!Prefix.empty()) {
+ LineNumber += Buffer.substr(0, CheckLoc).count('\n');
+ return Prefix;
+ }
+
+ // We didn't find any almost matches either, we are also done.
+ if (CheckLoc == StringRef::npos)
+ return StringRef();
+
+ LineNumber += Buffer.substr(0, CheckLoc + 1).count('\n');
+
+ // Advance to the last possible match we found and try again.
+ Buffer = Buffer.drop_front(CheckLoc + 1);
+ }
+
+ return StringRef();
+}
+