ui/base/template_expressions.cc

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ui/base/template_expressions.h"
   6
   7 #include "base/logging.h"
   8
   9 namespace ui {
  10
  11 std::string ReplaceTemplateExpressions(
  12     base::StringPiece format_string,
  13     const std::map<base::StringPiece, std::string>& substitutions) {
  14   std::string formatted;
  15   const size_t kValueLengthGuess = 16;
  16   formatted.reserve(format_string.length() +
  17                     substitutions.size() * kValueLengthGuess);
  18   base::StringPiece::const_iterator i = format_string.begin();
  19   while (i < format_string.end()) {
  20     if (*i == '$' && i + 1 < format_string.end() && i[1] == '{') {
  21       size_t key_start = i + strlen("${") - format_string.begin();
  22       size_t key_length = format_string.find('}', key_start);
  23       if (key_length == base::StringPiece::npos)
  24         NOTREACHED() << "TemplateExpression missing ending brace '}'";
  25       key_length -= key_start;
  26       base::StringPiece key(format_string.begin() + key_start, key_length);
  27       const auto& replacement = substitutions.find(key);
  28       if (replacement != substitutions.end()) {
  29         formatted.append(replacement->second);
  30         i += strlen("${") + key_length + strlen("}");
  31         continue;
  32       } else {
  33         NOTREACHED() << "TemplateExpression key not found: " << key;
  34       }
  35     }
  36     formatted.push_back(*i);
  37     ++i;
  38   }
  39   return formatted;
  40 }
  41
  42 }  // namespace ui