YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

// Copyright (c) YugaByte, 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 "yb/util/string_trim.h"

#include <sstream> // for istringstream

#include <string>

#include <regex>

using std::string;

using std::vector;

using std::istringstream;

namespace yb {

namespace util {

string ApplyEagerLineContinuation(const string& s) {

  string result;

  size_t length = s.size();

  for (size_t i = 0; i < length; ++i) {

    while (i > 0 && s[i - 1] == '\\' && s[i] == '\n') {

      // Remove the previous character (backslash).

      result.resize(result.size() - 1);

      // Consume the leading whitespace on the new line. This may be different from how backslash

      // line continuation works in other places, but this is what we need for some of our expected

      // test output handling.

      ++i;  // skip the new line

      // Skip whitespace on the new line.

      while (i < length && std::isspace(s[i], std::locale::classic())) {

        ++i;

      }

    }

    if (i < length) {

      result.push_back(s[i]);

    }

  }

  return result;

}

namespace {

size_t CountLeadingSpaces(const string& line) {

  size_t num_spaces = 0;

  for (char c : line) {

    if (c != ' ')

      break;

    num_spaces++;

  }

  return num_spaces;

}

}  // anonymous namespace

string LeftShiftTextBlock(const std::string& s) {

  istringstream input(s);

  vector<string> lines;

  // Split the string into lines.  This could be implemented with boost::split with less data

  // copying and memory allocation.

  while (!input.eof()) {

    lines.emplace_back();

    getline(input, lines.back());

  }

  size_t min_leading_spaces = std::numeric_limits<int>::max();

  for (const string& line : lines) {

    const auto num_spaces = CountLeadingSpaces(line);

    // We're not counting empty lines when calculating the minimum number of leading spaces.

    // TODO: we're counting all-space lines as empty but not if they have e.g. tab chracters.

    if (num_spaces != line.size() && num_spaces < min_leading_spaces) {

      min_leading_spaces = num_spaces;

    }

  }

  string result;

  bool need_newline = false;

  for (const string& line : lines) {

    if (need_newline) {

      result.push_back('\n');

    }

    need_newline = true;

    if (min_leading_spaces <= line.size()) {

      result += line.substr(min_leading_spaces, line.size() - min_leading_spaces);

    }

  }

  return result;

}

std::string TrimCppComments(const std::string& s) {

  static const std::regex kCppCommentRE = std::regex("\\s*//[^\n]+");

  return std::regex_replace(s, kCppCommentRE, "");

}

std::string TrimTrailingWhitespaceFromEveryLine(std::string s) {

  auto write_it = s.begin();

  auto first_it_to_delete = s.begin();

  for (auto i = s.begin(); i != s.end();) {

    auto ch = *i;

    ++i;

    if (ch == '\r' || ch == '\n') {

      *write_it++ = ch;

      first_it_to_delete = i;

    } else if (!std::isspace(ch)) {

      while (first_it_to_delete != i) {

        *write_it++ = *first_it_to_delete++;

      }

      first_it_to_delete = i;

    }

  }

  s.erase(write_it, s.end());

  return s;

}

}  // namespace util

}  // namespace yb