src: refactor SplitString in util

PR-URL: #48491
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>

Author: anonrig

src/node_options.cc

@@ -11,10 +11,11 @@
 #endif
 
 #include <errno.h>
-#include <sstream>
-#include <limits>
 #include <algorithm>
 #include <cstdlib>  // strtoul, errno
+#include <limits>
+#include <sstream>
+#include <string_view>
 
 using v8::Boolean;
 using v8::Context;
@@ -50,14 +51,15 @@ void DebugOptions::CheckOptions(std::vector<std::string>* errors,
                       "`node --inspect-brk` instead.");
   }
 
-  std::vector<std::string> destinations =
-      SplitString(inspect_publish_uid_string, ',');
+  using std::string_view_literals::operator""sv;
+  const std::vector<std::string_view> destinations =
+      SplitString(inspect_publish_uid_string, ","sv);
   inspect_publish_uid.console = false;
   inspect_publish_uid.http = false;
-  for (const std::string& destination : destinations) {
-    if (destination == "stderr") {
+  for (const std::string_view destination : destinations) {
+    if (destination == "stderr"sv) {
       inspect_publish_uid.console = true;
-    } else if (destination == "http") {
+    } else if (destination == "http"sv) {
       inspect_publish_uid.http = true;
     } else {
       errors->push_back("--inspect-publish-uid destination can be "

src/node_v8_platform-inl.h

@@ -4,6 +4,7 @@
 #if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
 
 #include <memory>
+#include <string_view>
 
 #include "env-inl.h"
 #include "node.h"
@@ -126,15 +127,23 @@ struct V8Platform {
   }
 
   inline void StartTracingAgent() {
+    constexpr auto convert_to_set =
+        [](std::vector<std::string_view> categories) -> std::set<std::string> {
+      std::set<std::string> out;
+      for (const auto s : categories) {
+        out.emplace(s);
+      }
+      return out;
+    };
     // Attach a new NodeTraceWriter only if this function hasn't been called
     // before.
     if (tracing_file_writer_.IsDefaultHandle()) {
-      std::vector<std::string> categories =
-          SplitString(per_process::cli_options->trace_event_categories, ',');
+      using std::string_view_literals::operator""sv;
+      const std::vector<std::string_view> categories =
+          SplitString(per_process::cli_options->trace_event_categories, ","sv);
 
       tracing_file_writer_ = tracing_agent_->AddClient(
-          std::set<std::string>(std::make_move_iterator(categories.begin()),
-                                std::make_move_iterator(categories.end())),
+          convert_to_set(categories),
           std::unique_ptr<tracing::AsyncTraceWriter>(
               new tracing::NodeTraceWriter(
                   per_process::cli_options->trace_event_file_pattern)),

src/permission/fs_permission.cc

@@ -9,6 +9,7 @@
 #include <algorithm>
 #include <filesystem>
 #include <string>
+#include <string_view>
 #include <vector>
 
 namespace {
@@ -74,8 +75,9 @@ namespace permission {
 // allow = '*'
 // allow = '/tmp/,/home/example.js'
 void FSPermission::Apply(const std::string& allow, PermissionScope scope) {
-  for (const auto& res : SplitString(allow, ',')) {
-    if (res == "*") {
+  using std::string_view_literals::operator""sv;
+  for (const std::string_view res : SplitString(allow, ","sv)) {
+    if (res == "*"sv) {
       if (scope == PermissionScope::kFileSystemRead) {
         deny_all_in_ = false;
         allow_all_in_ = true;
@@ -85,7 +87,7 @@ void FSPermission::Apply(const std::string& allow, PermissionScope scope) {
       }
       return;
     }
-    GrantAccess(scope, res);
+    GrantAccess(scope, std::string(res.data(), res.size()));
   }
 }
 

src/util.cc

@@ -169,19 +169,21 @@ std::string GetHumanReadableProcessName() {
   return SPrintF("%s[%d]", GetProcessTitle("Node.js"), uv_os_getpid());
 }
 
-std::vector<std::string> SplitString(const std::string& in,
-                                     char delim,
-                                     bool skipEmpty) {
-  std::vector<std::string> out;
-  if (in.empty())
-    return out;
-  std::istringstream in_stream(in);
-  while (in_stream.good()) {
-    std::string item;
-    std::getline(in_stream, item, delim);
-    if (item.empty() && skipEmpty) continue;
-    out.emplace_back(std::move(item));
+std::vector<std::string_view> SplitString(const std::string_view in,
+                                          const std::string_view delim) {
+  std::vector<std::string_view> out;
+
+  for (auto first = in.data(), second = in.data(), last = first + in.size();
+       second != last && first != last;
+       first = second + 1) {
+    second =
+        std::find_first_of(first, last, std::cbegin(delim), std::cend(delim));
+
+    if (first != second) {
+      out.emplace_back(first, second - first);
+    }
   }
+
   return out;
 }
 

src/util.h

@@ -685,9 +685,8 @@ struct FunctionDeleter {
 template <typename T, void (*function)(T*)>
 using DeleteFnPtr = typename FunctionDeleter<T, function>::Pointer;
 
-std::vector<std::string> SplitString(const std::string& in,
-                                     char delim,
-                                     bool skipEmpty = true);
+std::vector<std::string_view> SplitString(const std::string_view in,
+                                          const std::string_view delim);
 
 inline v8::MaybeLocal<v8::Value> ToV8Value(v8::Local<v8::Context> context,
                                            std::string_view str,