[wpiutil] Change StringExtras split() to template (#7636)

It now calls back a function for each part rather than creating a SmallVector.

wpinet/src/main/native/cpp/HttpUtil.cpp

@@ -98,9 +98,7 @@ std::string_view EscapeHTML(std::string_view str, SmallVectorImpl<char>& buf) {
 }
 
 HttpQueryMap::HttpQueryMap(std::string_view query) {
-  SmallVector<std::string_view, 16> queryElems;
-  split(query, queryElems, '&', 100, false);
-  for (auto elem : queryElems) {
+  split(query, '&', 100, false, [&](auto elem) {
     auto [nameEsc, valueEsc] = split(elem, '=');
     SmallString<64> nameBuf;
     bool err = false;
@@ -109,7 +107,7 @@ HttpQueryMap::HttpQueryMap(std::string_view query) {
     if (!err) {
       m_elems.try_emplace(name, valueEsc);
     }
-  }
+  });
 }
 
 std::optional<std::string_view> HttpQueryMap::Get(
@@ -132,9 +130,7 @@ HttpPath::HttpPath(std::string_view path) {
     m_pathEnds.emplace_back(0);
     return;
   }
-  wpi::SmallVector<std::string_view, 16> pathElems;
-  split(path, pathElems, '/', 100, false);
-  for (auto elem : pathElems) {
+  split(path, '/', 100, false, [&](auto elem) {
     SmallString<64> buf;
     bool err = false;
     auto val = wpi::UnescapeURI(elem, buf, &err);
@@ -144,7 +140,7 @@ HttpPath::HttpPath(std::string_view path) {
     }
     m_pathBuf += val;
     m_pathEnds.emplace_back(m_pathBuf.size());
-  }
+  });
 }
 
 bool HttpPath::startswith(size_t start,

wpinet/src/main/native/cpp/WebSocketServer.cpp

@@ -5,6 +5,7 @@
 #include "wpinet/WebSocketServer.h"
 
 #include <memory>
+#include <string>
 #include <utility>
 
 #include <wpi/StringExtras.h>
@@ -31,14 +32,12 @@ WebSocketServerHelper::WebSocketServerHelper(HttpParser& req) {
       m_version = value;
     } else if (equals_lower(name, "sec-websocket-protocol")) {
       // Protocols are comma delimited, repeated headers add to list
-      SmallVector<std::string_view, 2> protocols;
-      split(value, protocols, ",", -1, false);
-      for (auto protocol : protocols) {
+      split(value, ',', -1, false, [&](auto protocol) {
         protocol = trim(protocol);
         if (!protocol.empty()) {
           m_protocols.emplace_back(protocol);
         }
-      }
+      });
     }
   });
   req.headersComplete.connect([&req, this](bool) {
@@ -53,7 +52,22 @@ std::pair<bool, std::string_view> WebSocketServerHelper::MatchProtocol(
   if (protocols.empty() && m_protocols.empty()) {
     return {true, {}};
   }
-  for (auto protocol : protocols) {
+  for (auto&& protocol : protocols) {
+    for (auto&& clientProto : m_protocols) {
+      if (protocol == clientProto) {
+        return {true, protocol};
+      }
+    }
+  }
+  return {false, {}};
+}
+
+std::pair<bool, std::string_view> WebSocketServerHelper::MatchProtocol(
+    std::span<const std::string> protocols) {
+  if (protocols.empty() && m_protocols.empty()) {
+    return {true, {}};
+  }
+  for (auto&& protocol : protocols) {
     for (auto&& clientProto : m_protocols) {
       if (protocol == clientProto) {
         return {true, protocol};
@@ -101,9 +115,7 @@ WebSocketServer::WebSocketServer(uv::Stream& stream,
     }
 
     // Negotiate sub-protocol
-    SmallVector<std::string_view, 2> protocols{m_protocols.begin(),
-                                               m_protocols.end()};
-    std::string_view protocol = m_helper.MatchProtocol(protocols).second;
+    std::string_view protocol = m_helper.MatchProtocol(m_protocols).second;
 
     // Disconnect our header reader
     m_dataConn.disconnect();