From 3ec0d4ec961cb0c67ff1603b83a6026d9f3abbb5 Mon Sep 17 00:00:00 2001
From: Joel Rosdahl <joel@rosdahl.net>
Date: Sun, 16 Oct 2022 10:17:01 +0200
Subject: [PATCH] refactor: Avoid an extra data copy when rewriting stdout

---
 src/ccache.cpp                      | 10 ++++++----
 src/core/MsvcShowIncludesOutput.cpp |  6 +++---
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/ccache.cpp b/src/ccache.cpp
index 308685671..861bc5b1e 100644
--- a/src/ccache.cpp
+++ b/src/ccache.cpp
@@ -950,7 +950,7 @@ rewrite_stdout_from_compiler(const Context& ctx, util::Bytes&& stdout_data)
   using Mode = Tokenizer::Mode;
   using IncludeDelimiter = Tokenizer::IncludeDelimiter;
   if (!stdout_data.empty()) {
-    std::string new_stdout_text;
+    util::Bytes new_stdout_data;
     for (const auto line : Tokenizer(util::to_string_view(stdout_data),
                                      "\n",
                                      Mode::include_empty,
@@ -973,12 +973,14 @@ rewrite_stdout_from_compiler(const Context& ctx, util::Bytes&& stdout_data)
           ctx, Util::normalize_concrete_absolute_path(abs_inc_path));
         std::string line_with_rel_inc =
           util::replace_first(orig_line, abs_inc_path, rel_inc_path);
-        new_stdout_text.append(line_with_rel_inc);
+        new_stdout_data.insert(new_stdout_data.begin(),
+                               line_with_rel_inc.data(),
+                               line_with_rel_inc.size());
       } else {
-        new_stdout_text.append(line.data(), line.length());
+        new_stdout_data.insert(new_stdout_data.end(), line.data(), line.size());
       }
     }
-    return util::Bytes(new_stdout_text.data(), new_stdout_text.size());
+    return new_stdout_data;
   } else {
     return std::move(stdout_data);
   }
diff --git a/src/core/MsvcShowIncludesOutput.cpp b/src/core/MsvcShowIncludesOutput.cpp
index 5289eadc6..311a1bcbb 100644
--- a/src/core/MsvcShowIncludesOutput.cpp
+++ b/src/core/MsvcShowIncludesOutput.cpp
@@ -61,16 +61,16 @@ strip_includes(const Context& ctx, util::Bytes&& stdout_data)
     return std::move(stdout_data);
   }
 
-  std::string new_stdout_text;
+  util::Bytes new_stdout_data;
   for (const auto line : Tokenizer(util::to_string_view(stdout_data),
                                    "\n",
                                    Mode::include_empty,
                                    IncludeDelimiter::yes)) {
     if (!util::starts_with(line, ctx.config.msvc_dep_prefix())) {
-      new_stdout_text.append(line.data(), line.length());
+      new_stdout_data.insert(new_stdout_data.end(), line.data(), line.size());
     }
   }
-  return util::Bytes(new_stdout_text.data(), new_stdout_text.size());
+  return new_stdout_data;
 }
 
 } // namespace core::MsvcShowIncludesOutput
-- 
2.47.2