Address reviewer comments

src/logging.cc

@@ -2206,59 +2206,46 @@ static string ShellEscape(const string& src) {
   }
   return result;
 }
-#endif
-
-// Trim whitespace from the start of the provided string.
-static inline void ltrim(std::string &s) {
-  s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](char ch) {
-      return std::isspace(ch) == 0;
-  }));
-}
-
-// Trim whitespace from the end of the provided string.
-static inline void rtrim(std::string &s) {
-  s.erase(std::find_if(s.rbegin(), s.rend(), [](char ch) {
-      return std::isspace(ch) == 0;
-  }).base(), s.end());
-}
 
 // Trim whitespace from both ends of the provided string.
 static inline void trim(std::string &s) {
-  rtrim(s);
-  ltrim(s);
+  const auto toRemove = [](char ch) { return std::isspace(ch) == 0; };
+  s.erase(s.begin(), std::find_if(s.begin(), s.end(), toRemove));
+  s.erase(std::find_if(s.rbegin(), s.rend(), toRemove).base(), s.end());
 }
+#endif
 
 // use_logging controls whether the logging functions LOG/VLOG are used
 // to log errors.  It should be set to false when the caller holds the
 // log_mutex.
 static bool SendEmailInternal(const char*dest, const char *subject,
                               const char*body, bool use_logging) {
 #ifndef GLOG_OS_EMSCRIPTEN
-  // We validate the provided email addresses using the same regular expression
-  // that HTML5 uses[1], except that we require the address to start with an
-  // alpha-numeric character. This is because we don't want to allow email
-  // addresses that start with a special character, such as a pipe or dash,
-  // which could be misunderstood as a command-line flag by certain versions
-  // of `mail` that are vulnerable to command injection.[2]
-  // [1] https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address
-  // [2] e.g. https://nvd.nist.gov/vuln/detail/CVE-2004-2771
-  const std::regex pattern("^[a-zA-Z0-9]"
-      "[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]*@[a-zA-Z0-9]"
-      "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9]"
-      "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$");
-
   if (dest && *dest) {
     // Split the comma-separated list of email addresses, validate each one and
     // build a sanitized new comma-separated string without whitespace.
-    std::stringstream ss(dest);
+    std::istringstream ss(dest);
     std::ostringstream sanitized_dests;
     std::string s;
     while (std::getline(ss, s, ',')) {
       trim(s);
       if (s.empty()) {
         continue;
       }
-      if (!std::regex_match(s, pattern)) {
+      // We validate the provided email addresses using the same regular
+      // expression that HTML5 uses[1], except that we require the address to
+      // start with an alpha-numeric character. This is because we don't want to
+      // allow email addresses that start with a special character, such as a
+      // pipe or dash, which could be misunderstood as a command-line flag by
+      // certain versions of `mail` that are vulnerable to command injection.[2]
+      // [1] https://html.spec.whatwg.org/multipage/input.html#valid-e-mail-address
+      // [2] e.g. https://nvd.nist.gov/vuln/detail/CVE-2004-2771
+      if (!std::regex_match(
+              s,
+              std::regex("^[a-zA-Z0-9]"
+                         "[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]*@[a-zA-Z0-9]"
+                         "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\\.[a-zA-Z0-9]"
+                         "(?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$"))) {
         if (use_logging) {
           VLOG(1) << "Invalid destination email address:" << s;
         } else {