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- /*
- * Copyright 2017-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/logging/LogName.h>
- namespace {
- constexpr bool isSeparator(char c) {
- return c == '.' || c == '/' || c == '\\';
- }
- } // namespace
- namespace folly {
- std::string LogName::canonicalize(StringPiece input) {
- std::string cname;
- cname.reserve(input.size());
- // Ignore trailing category separator characters
- size_t end = input.size();
- while (end > 0 && isSeparator(input[end - 1])) {
- --end;
- }
- bool ignoreSeparator = true;
- for (size_t idx = 0; idx < end; ++idx) {
- if (isSeparator(input[idx])) {
- if (ignoreSeparator) {
- continue;
- }
- cname.push_back('.');
- ignoreSeparator = true;
- } else {
- cname.push_back(input[idx]);
- ignoreSeparator = false;
- }
- }
- return cname;
- }
- size_t LogName::hash(StringPiece name) {
- // Code based on StringPiece::hash(), but which ignores leading and trailing
- // category separator characters, as well as multiple consecutive separator
- // characters, so equivalent names result in the same hash.
- uint32_t hash = 5381;
- size_t end = name.size();
- while (end > 0 && isSeparator(name[end - 1])) {
- --end;
- }
- bool ignoreSeparator = true;
- for (size_t idx = 0; idx < end; ++idx) {
- uint8_t value;
- if (isSeparator(name[idx])) {
- if (ignoreSeparator) {
- continue;
- }
- value = '.';
- ignoreSeparator = true;
- } else {
- value = static_cast<uint8_t>(name[idx]);
- ignoreSeparator = false;
- }
- hash = ((hash << 5) + hash) + value;
- }
- return hash;
- }
- int LogName::cmp(StringPiece a, StringPiece b) {
- // Ignore trailing separators
- auto stripTrailingSeparators = [](StringPiece& s) {
- while (!s.empty() && isSeparator(s.back())) {
- s.uncheckedSubtract(1);
- }
- };
- stripTrailingSeparators(a);
- stripTrailingSeparators(b);
- // Advance ptr until it no longer points to a category separator.
- // This is used to skip over consecutive sequences of separator characters.
- auto skipOverSeparators = [](StringPiece& s) {
- while (!s.empty() && isSeparator(s.front())) {
- s.uncheckedAdvance(1);
- }
- };
- bool ignoreSeparator = true;
- while (true) {
- if (ignoreSeparator) {
- skipOverSeparators(a);
- skipOverSeparators(b);
- }
- if (a.empty()) {
- return b.empty() ? 0 : -1;
- } else if (b.empty()) {
- return 1;
- }
- if (isSeparator(a.front())) {
- if (!isSeparator(b.front())) {
- return '.' - b.front();
- }
- ignoreSeparator = true;
- } else {
- if (a.front() != b.front()) {
- return a.front() - b.front();
- }
- ignoreSeparator = false;
- }
- a.uncheckedAdvance(1);
- b.uncheckedAdvance(1);
- }
- }
- StringPiece LogName::getParent(StringPiece name) {
- if (name.empty()) {
- return name;
- }
- ssize_t idx = name.size();
- // Skip over any trailing separator characters
- while (idx > 0 && isSeparator(name[idx - 1])) {
- --idx;
- }
- // Now walk backwards to the next separator character
- while (idx > 0 && !isSeparator(name[idx - 1])) {
- --idx;
- }
- // And again skip over any separator characters, in case there are multiple
- // repeated characters.
- while (idx > 0 && isSeparator(name[idx - 1])) {
- --idx;
- }
- return StringPiece(name.begin(), idx);
- }
- } // namespace folly
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