[vcpkg] Use XDG/LOCALAPPDATA for default binary caching path

toolsrc/include/vcpkg/base/system.h

@@ -9,7 +9,13 @@ namespace vcpkg::System
 {
     Optional<std::string> get_environment_variable(ZStringView varname) noexcept;
 
-    ExpectedS<std::string> get_home_dir() noexcept;
+    const ExpectedS<fs::path>& get_home_dir() noexcept;
+
+    const ExpectedS<fs::path>& get_platform_cache_home() noexcept;
+
+#ifdef _WIN32
+    const ExpectedS<fs::path>& get_appdata_local() noexcept;
+#endif
 
     Optional<std::string> get_registry_string(void* base_hkey, StringView subkey, StringView valuename);
 

toolsrc/src/vcpkg/base/system.cpp

@@ -105,17 +105,92 @@ namespace vcpkg
 #endif // defined(_WIN32)
     }
 
-    ExpectedS<std::string> System::get_home_dir() noexcept
+    const ExpectedS<fs::path>& System::get_home_dir() noexcept
     {
+        static ExpectedS<fs::path> s_home = []() -> ExpectedS<fs::path> {
 #ifdef _WIN32
-        auto maybe_home = System::get_environment_variable("USERPROFILE");
-        if (!maybe_home.has_value() || maybe_home.get()->empty())
-            return {"unable to read %USERPROFILE%", ExpectedRightTag{}};
+#define HOMEVAR "%USERPROFILE%"
+            auto maybe_home = System::get_environment_variable("USERPROFILE");
+            if (!maybe_home.has_value() || maybe_home.get()->empty())
+                return {"unable to read " HOMEVAR, ExpectedRightTag{}};
 #else
-        auto maybe_home = System::get_environment_variable("HOME");
-        if (!maybe_home.has_value() || maybe_home.get()->empty()) return {"unable to read $HOME", ExpectedRightTag{}};
+#define HOMEVAR "$HOME"
+            auto maybe_home = System::get_environment_variable("HOME");
+            if (!maybe_home.has_value() || maybe_home.get()->empty())
+                return {"unable to read " HOMEVAR, ExpectedRightTag{}};
+#endif
+
+            auto p = fs::u8path(*maybe_home.get());
+            if (!p.is_absolute()) return {HOMEVAR " was not an absolute path", ExpectedRightTag{}};
+
+            return {std::move(p), ExpectedLeftTag{}};
+        }();
+        return s_home;
+#undef HOMEVAR
+    }
+
+#ifdef _WIN32
+    const ExpectedS<fs::path>& System::get_appdata_local() noexcept
+    {
+        static ExpectedS<fs::path> s_home = []() -> ExpectedS<fs::path> {
+            auto maybe_home = System::get_environment_variable("LOCALAPPDATA");
+            if (!maybe_home.has_value() || maybe_home.get()->empty())
+                return {"unable to read %LOCALAPPDATA%", ExpectedRightTag{}};
+
+            auto p = fs::u8path(*maybe_home.get());
+            if (!p.is_absolute()) return {"%LOCALAPPDATA% was not an absolute path", ExpectedRightTag{}};
+
+            return {std::move(p), ExpectedLeftTag{}};
+        }();
+        return s_home;
+    }
+#else
+    static const ExpectedS<fs::path>& get_xdg_config_home() noexcept
+    {
+        static ExpectedS<fs::path> s_home = [] {
+            auto maybe_home = System::get_environment_variable("XDG_CONFIG_HOME");
+            if (auto p = maybe_home.get())
+            {
+                return ExpectedS<fs::path>(fs::u8path(*p));
+            }
+            else
+            {
+                return System::get_home_dir().map([](fs::path home) {
+                    home /= fs::u8path(".config");
+                    return home;
+                });
+            }
+        }();
+        return s_home;
+    }
+
+    static const ExpectedS<fs::path>& get_xdg_cache_home() noexcept
+    {
+        static ExpectedS<fs::path> s_home = [] {
+            auto maybe_home = System::get_environment_variable("XDG_CACHE_HOME");
+            if (auto p = maybe_home.get())
+            {
+                return ExpectedS<fs::path>(fs::u8path(*p));
+            }
+            else
+            {
+                return System::get_home_dir().map([](fs::path home) {
+                    home /= fs::u8path(".cache");
+                    return home;
+                });
+            }
+        }();
+        return s_home;
+    }
+#endif
+
+    const ExpectedS<fs::path>& System::get_platform_cache_home() noexcept
+    {
+#ifdef _WIN32
+        return System::get_appdata_local();
+#else
+        return get_xdg_cache_home();
 #endif
-        return {std::move(*maybe_home.get()), ExpectedLeftTag{}};
     }
 
 #if defined(_WIN32)
@@ -150,7 +225,7 @@ namespace vcpkg
         ret.pop_back(); // remove extra trailing null byte
         return Strings::to_utf8(ret);
     }
-#else // ^^^ defined(_WIN32) / !defined(_WIN32) vvv
+#else  // ^^^ defined(_WIN32) / !defined(_WIN32) vvv
     Optional<std::string> System::get_registry_string(void*, StringView, StringView) { return nullopt; }
 #endif // defined(_WIN32)
 

toolsrc/src/vcpkg/binarycaching.cpp

@@ -392,10 +392,11 @@ ExpectedS<std::unique_ptr<IBinaryProvider>> vcpkg::create_binary_provider_from_c
                     return add_error("unexpected arguments: binary config 'default' does not take more than 1 argument",
                                      segments[0].first);
 
-                auto maybe_home = System::get_home_dir();
+                auto&& maybe_home = System::get_platform_cache_home();
                 if (!maybe_home.has_value()) return add_error(maybe_home.error(), segments[0].first);
 
-                auto p = fs::u8path(maybe_home.value_or_exit(VCPKG_LINE_INFO)) / fs::u8path(".vcpkg/archives");
+                auto p = *maybe_home.get();
+                p /= fs::u8path("vcpkg/archives");
                 if (!p.is_absolute())
                     return add_error("default path was not absolute: " + p.u8string(), segments[0].first);
                 if (segments.size() == 2)

toolsrc/src/vcpkg/commands.integrate.cpp

@@ -155,17 +155,13 @@ namespace vcpkg::Commands::Integrate
 #if defined(_WIN32)
     static fs::path get_appdata_targets_path()
     {
-        static const fs::path LOCAL_APP_DATA =
-            fs::u8path(System::get_environment_variable("LOCALAPPDATA").value_or_exit(VCPKG_LINE_INFO));
-        return LOCAL_APP_DATA / fs::u8path("vcpkg/vcpkg.user.targets");
+        return System::get_appdata_local().value_or_exit(VCPKG_LINE_INFO) / fs::u8path("vcpkg/vcpkg.user.targets");
     }
 #endif
 #if defined(_WIN32)
     static fs::path get_appdata_props_path()
     {
-        static const fs::path LOCAL_APP_DATA =
-            fs::u8path(System::get_environment_variable("LOCALAPPDATA").value_or_exit(VCPKG_LINE_INFO));
-        return LOCAL_APP_DATA / "vcpkg" / "vcpkg.user.props";
+        return System::get_appdata_local().value_or_exit(VCPKG_LINE_INFO) / fs::u8path("vcpkg/vcpkg.user.props");
     }
 #endif
 
@@ -277,19 +273,20 @@ namespace vcpkg::Commands::Integrate
             const fs::path appdata_src_path2 = tmp_dir / "vcpkg.user.props";
             fs.write_contents(appdata_src_path2,
                               create_appdata_shortcut(paths.buildsystems_msbuild_props.u8string()),
-			      VCPKG_LINE_INFO);
+                              VCPKG_LINE_INFO);
             auto appdata_dst_path2 = get_appdata_props_path();
 
-            const auto rc2 = fs.copy_file(appdata_src_path2, appdata_dst_path2, fs::copy_options::overwrite_existing, ec);
+            const auto rc2 =
+                fs.copy_file(appdata_src_path2, appdata_dst_path2, fs::copy_options::overwrite_existing, ec);
 
             if (!rc2 || ec)
             {
                 System::print2(System::Color::error,
-                                "Error: Failed to copy file: ",
-                                appdata_src_path2.u8string(),
-                                " -> ",
-                                appdata_dst_path2.u8string(),
-								"\n");
+                               "Error: Failed to copy file: ",
+                               appdata_src_path2.u8string(),
+                               " -> ",
+                               appdata_dst_path2.u8string(),
+                               "\n");
                 Checks::exit_fail(VCPKG_LINE_INFO);
             }
         }

toolsrc/src/vcpkg/userconfig.cpp

@@ -4,35 +4,14 @@
 #include <vcpkg/base/lazy.h>
 #include <vcpkg/paragraphs.h>
 #include <vcpkg/userconfig.h>
-
-#if defined(_WIN32)
-namespace
-{
-    static vcpkg::Lazy<fs::path> s_localappdata;
-
-    static const fs::path& get_localappdata()
-    {
-        return s_localappdata.get_lazy([]() {
-            fs::path localappdata;
-            {
-                // Config path in AppDataLocal
-                wchar_t* localappdatapath = nullptr;
-                if (S_OK != SHGetKnownFolderPath(FOLDERID_LocalAppData, 0, nullptr, &localappdatapath)) __fastfail(1);
-                localappdata = localappdatapath;
-                CoTaskMemFree(localappdatapath);
-            }
-            return localappdata;
-        });
-    }
-}
-#endif
+#include <vcpkg/base/system.h>
 
 namespace vcpkg
 {
     fs::path get_user_dir()
     {
 #if defined(_WIN32)
-        return get_localappdata() / "vcpkg";
+        return System::get_appdata_local().value_or_exit(VCPKG_LINE_INFO) / "vcpkg";
 #else
         auto maybe_home = System::get_environment_variable("HOME");
         return fs::path(maybe_home.value_or("/var")) / ".vcpkg";