+/*
+ * Copyright 2004-present Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include <folly/experimental/logging/xlog.h>
+#include <folly/Synchronized.h>
+
+using folly::StringPiece;
+
+namespace folly {
+
+namespace {
+/**
+ * buck copies header files from their original location in the source tree
+ * and places them under buck-out/ with a path like
+ * buck-out/<rule-name-components>/<original-path>
+ *
+ * We want to strip off the buck-out/<rule-name-components> portion,
+ * so that the filename we use is just the original path in the source tree.
+ *
+ * The <rule-name-component> section should always end in a path component that
+ * includes a '#': it's format is <rule-name>#<parameters>, where <parameters>
+ * is a comma separated list that never includes '/'.
+ *
+ * Search for the first path component with a '#', and strip off everything up
+ * to this component.
+ */
+StringPiece stripBuckOutPrefix(StringPiece filename) {
+ size_t idx = 0;
+ while (true) {
+ auto end = filename.find('/', idx);
+ if (end == StringPiece::npos) {
+ // We were unable to find where the buck-out prefix should end.
+ return filename;
+ }
+
+ auto component = filename.subpiece(idx, end - idx);
+ if (component.find('#') != StringPiece::npos) {
+ return filename.subpiece(end + 1);
+ }
+ idx = end + 1;
+ }
+}
+} // unnamed namespace
+
+std::string getXlogCategoryNameForFile(StringPiece filename) {
+ // Buck mangles the directory layout for header files. Rather than including
+ // them from their original location, it moves them into deep directories
+ // inside buck-out, and includes them from there.
+ //
+ // If this path looks like a buck header directory, try to strip off the
+ // buck-specific portion.
+ if (filename.startsWith("buck-out/")) {
+ filename = stripBuckOutPrefix(filename);
+ }
+
+ std::string categoryName = filename.str();
+
+ // Translate slashes to dots, to turn the directory layout into
+ // a category hierarchy.
+ size_t lastDot = std::string::npos;
+ for (size_t n = 0; n < categoryName.size(); ++n) {
+ if (categoryName[n] == '/') {
+ categoryName[n] = '.';
+ lastDot = std::string::npos;
+ } else if (categoryName[n] == '.') {
+ lastDot = n;
+ }
+ }
+
+ // Strip off the filename extension, if one was present.
+ if (lastDot != std::string::npos) {
+ categoryName.resize(lastDot);
+ }
+ return categoryName;
+}
+}