From: Joel Rosdahl <joel@rosdahl.net>
Date: Sun, 13 Oct 2019 20:34:37 +0000 (+0200)
Subject: Use nonstd::string_view where appropriate
X-Git-Tag: v4.0~735
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=985193a5606659917029cd8fc6228c5329cedd78;p=thirdparty%2Fccache.git

Use nonstd::string_view where appropriate
---

diff --git a/dev.mk.in b/dev.mk.in
index f15defbaa..79ec28f74 100644
--- a/dev.mk.in
+++ b/dev.mk.in
@@ -42,10 +42,11 @@ non_third_party_headers = \
     src/Checksum.hpp \
     src/Compression.hpp \
     src/Compressor.hpp \
-    src/Decompressor.hpp \
     src/Config.hpp \
+    src/Decompressor.hpp \
     src/Error.hpp \
     src/File.hpp \
+    src/FormatNonStdStringView.hpp \
     src/NonCopyable.hpp \
     src/NullCompressor.hpp \
     src/NullDecompressor.hpp \
diff --git a/src/FormatNonstdStringView.hpp b/src/FormatNonstdStringView.hpp
new file mode 100644
index 000000000..63f7ae1be
--- /dev/null
+++ b/src/FormatNonstdStringView.hpp
@@ -0,0 +1,42 @@
+// Copyright (C) 2019 Joel Rosdahl and other contributors
+//
+// See doc/AUTHORS.adoc for a complete list of contributors.
+//
+// This program is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by the Free
+// Software Foundation; either version 3 of the License, or (at your option)
+// any later version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+// more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program; if not, write to the Free Software Foundation, Inc., 51
+// Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+#pragma once
+
+// Specialization of fmt::formatter for nonstd::string_view.
+namespace fmt {
+
+template<> struct formatter<nonstd::string_view>
+{
+  template<typename ParseContext>
+  constexpr auto
+  parse(ParseContext& ctx) -> decltype(ctx.begin())
+  {
+    return ctx.begin();
+  }
+
+  template<typename FormatContext>
+  auto
+  format(const nonstd::string_view& sv, FormatContext& ctx)
+    -> decltype(ctx.out())
+  {
+    return format_to(ctx.out(), "{:{}}", sv.data(), sv.length());
+  }
+};
+
+} // namespace fmt
diff --git a/src/Util.cpp b/src/Util.cpp
index 20aff655f..801291e02 100644
--- a/src/Util.cpp
+++ b/src/Util.cpp
@@ -18,6 +18,7 @@
 
 #include "Util.hpp"
 
+#include "FormatNonstdStringView.hpp"
 #include "ccache.hpp"
 
 #include <algorithm>
@@ -39,14 +40,14 @@ get_cache_files_internal(const std::string& dir,
   std::vector<std::string> directories;
   dirent* de;
   while ((de = readdir(d))) {
-    std::string name = de->d_name;
+    nonstd::string_view name(de->d_name);
     if (name == "" || name == "." || name == ".." || name == "CACHEDIR.TAG"
-        || name == "stats" || Util::starts_with(name, ".nfs")) {
+        || name == "stats" || name.starts_with(".nfs")) {
       continue;
     }
 
     if (name.length() == 1) {
-      directories.push_back(name);
+      directories.emplace_back(name);
     } else {
       files.push_back(
         std::make_shared<CacheFile>(fmt::format("{}/{}", dir, name)));
@@ -71,8 +72,8 @@ get_cache_files_internal(const std::string& dir,
 
 namespace Util {
 
-std::string
-base_name(const std::string& path)
+nonstd::string_view
+base_name(nonstd::string_view path)
 {
   size_t n = path.rfind('/');
 #ifdef _WIN32
@@ -85,10 +86,11 @@ base_name(const std::string& path)
 }
 
 bool
-create_dir(const std::string& dir)
+create_dir(nonstd::string_view dir)
 {
+  std::string dir_str(dir);
   struct stat st;
-  if (stat(dir.c_str(), &st) == 0) {
+  if (stat(dir_str.c_str(), &st) == 0) {
     if (S_ISDIR(st.st_mode)) {
       return true;
     } else {
@@ -99,7 +101,7 @@ create_dir(const std::string& dir)
     if (!create_dir(Util::dir_name(dir))) {
       return false;
     }
-    int result = mkdir(dir.c_str(), 0777);
+    int result = mkdir(dir_str.c_str(), 0777);
     // Treat an already existing directory as OK since the file system could
     // have changed in between calling stat and actually creating the
     // directory. This can happen when there are multiple instances of ccache
@@ -112,17 +114,17 @@ create_dir(const std::string& dir)
 }
 
 std::pair<int, std::string>
-create_temp_fd(const std::string& path_prefix)
+create_temp_fd(nonstd::string_view path_prefix)
 {
-  char* tmp_path = x_strdup(path_prefix.c_str());
+  char* tmp_path = x_strndup(path_prefix.data(), path_prefix.length());
   int fd = create_tmp_fd(&tmp_path);
   std::string actual_path = tmp_path;
   free(tmp_path);
   return {fd, actual_path};
 }
 
-std::string
-dir_name(const std::string& path)
+nonstd::string_view
+dir_name(nonstd::string_view path)
 {
   size_t n = path.rfind('/');
 #ifdef _WIN32
@@ -138,12 +140,9 @@ dir_name(const std::string& path)
 }
 
 bool
-ends_with(const std::string& string, const std::string& suffix)
+ends_with(nonstd::string_view string, nonstd::string_view suffix)
 {
-  return suffix.length() <= string.length()
-         && string.compare(
-              string.length() - suffix.length(), suffix.length(), suffix)
-              == 0;
+  return string.ends_with(suffix);
 }
 
 void
@@ -212,10 +211,9 @@ read_file(const std::string& path)
 }
 
 bool
-starts_with(const std::string& string, const std::string& prefix)
+starts_with(nonstd::string_view string, nonstd::string_view prefix)
 {
-  return prefix.length() <= string.length()
-         && string.compare(0, prefix.length(), prefix) == 0;
+  return string.starts_with(prefix);
 }
 
 std::string
diff --git a/src/Util.hpp b/src/Util.hpp
index f75a51dda..53a388014 100644
--- a/src/Util.hpp
+++ b/src/Util.hpp
@@ -22,6 +22,8 @@
 
 #include "CacheFile.hpp"
 
+#include "third_party/nonstd/string_view.hpp"
+
 #include <functional>
 #include <memory>
 #include <string>
@@ -37,7 +39,7 @@ typedef std::function<void(const std::string& /*dir_path*/,
   SubdirVisitor;
 
 // Get base name of path.
-std::string base_name(const std::string& path);
+nonstd::string_view base_name(nonstd::string_view path);
 
 // Get an integer value from bytes in big endian order.
 //
@@ -72,7 +74,7 @@ big_endian_to_int(const uint8_t* buffer, uint8_t& value)
 // Create a directory if needed, including its parents if needed.
 //
 // Returns true if the directory exists or could be created, otherwise false.
-bool create_dir(const std::string& dir);
+bool create_dir(nonstd::string_view dir);
 
 // Create a unique temporary file.
 //
@@ -82,13 +84,13 @@ bool create_dir(const std::string& dir);
 //
 // Returns the open file descriptor (in read/write mode) and the actual
 // filename.
-std::pair<int, std::string> create_temp_fd(const std::string& path_prefix);
+std::pair<int, std::string> create_temp_fd(nonstd::string_view path_prefix);
 
 // Get directory name of path.
-std::string dir_name(const std::string& path);
+nonstd::string_view dir_name(nonstd::string_view path);
 
 // Return true if suffix is a suffix of string.
-bool ends_with(const std::string& string, const std::string& suffix);
+bool ends_with(nonstd::string_view string, nonstd::string_view suffix);
 
 // Call a function for each subdir (0-9a-f) in the cache.
 //
@@ -163,7 +165,7 @@ int parse_int(const std::string& value);
 std::string read_file(const std::string& path);
 
 // Return true if prefix is a prefix of string.
-bool starts_with(const std::string& string, const std::string& prefix);
+bool starts_with(nonstd::string_view string, nonstd::string_view prefix);
 
 // Strip whitespace from left and right side of a string.
 [[gnu::warn_unused_result]] std::string