manifest install: Cache compiler information for change detection

include/vcpkg/base/files.h

@@ -185,6 +185,9 @@ namespace vcpkg
         virtual FileType symlink_status(const Path& target, std::error_code& ec) const = 0;
         FileType symlink_status(const Path& target, LineInfo li) const noexcept;
 
+        virtual int64_t last_write_time(const Path& target, std::error_code& ec) const = 0;
+        int64_t last_write_time(const Path& target, LineInfo li) const noexcept;
+
         // absolute/system_complete + lexically_normal + fixup_win32_path_case
         // we don't use real canonical due to issues like:
         // https://github.com/microsoft/vcpkg/issues/16614 (canonical breaking on some older Windows Server containers)

include/vcpkg/base/jsonreader.h

@@ -302,6 +302,15 @@ namespace vcpkg::Json
         static const NaturalNumberDeserializer instance;
     };
 
+    struct Int64Deserializer final : IDeserializer<int64_t>
+    {
+        LocalizedString type_name() const override;
+
+        Optional<int64_t> visit_integer(Reader&, int64_t value) const override { return value; }
+
+        static Int64Deserializer instance;
+    };
+
     struct BooleanDeserializer final : IDeserializer<bool>
     {
         virtual LocalizedString type_name() const override;
@@ -358,4 +367,5 @@ namespace vcpkg::Json
         virtual Optional<std::string> visit_string(Json::Reader&, StringView sv) const override;
         static const FeatureNameDeserializer instance;
     };
+
 }

include/vcpkg/base/message-data.inc.h

@@ -140,6 +140,7 @@ DECLARE_MESSAGE(AndroidHomeDirMissingProps,
                 "source.properties missing in {env_var} directory: {path}")
 DECLARE_MESSAGE(AnExactVersionString, (), "", "an exact version string")
 DECLARE_MESSAGE(AnIdentifer, (), "", "an identifier")
+DECLARE_MESSAGE(AnInt64, (), "", "a 64-bit integer")
 DECLARE_MESSAGE(AnObjectContainingVcpkgArtifactsMetadata,
                 (),
                 "'vcpkg-artifacts' is the name of the product feature and should not be localized",

include/vcpkg/commands.build.h

@@ -260,6 +260,8 @@ namespace vcpkg
         std::string id;
         std::string version;
         std::string hash;
+        Path c_compiler_path;
+        Path cxx_compiler_path;
     };
 
     struct AbiInfo

include/vcpkg/installedpaths.h

@@ -22,6 +22,10 @@ namespace vcpkg
         Path vcpkg_dir_updates() const { return vcpkg_dir() / "updates"; }
         Path lockfile_path() const { return vcpkg_dir() / "vcpkg-lock.json"; }
         Path triplet_dir(Triplet t) const { return m_root / t.canonical_name(); }
+        Path compiler_info_cache_file(Triplet t) const
+        {
+            return vcpkg_dir() / "compiler_info_cache" / t.canonical_name();
+        }
         Path share_dir(const PackageSpec& p) const { return triplet_dir(p.triplet()) / "share" / p.name(); }
         Path usage_file(const PackageSpec& p) const { return share_dir(p) / "usage"; }
         Path vcpkg_port_config_cmake(const PackageSpec& p) const { return share_dir(p) / "vcpkg-port-config.cmake"; }

locales/messages.json

@@ -130,6 +130,7 @@
   "AnArtifactsRegistry": "an artifacts registry",
   "AnExactVersionString": "an exact version string",
   "AnIdentifer": "an identifier",
+  "AnInt64": "a 64-bit integer",
   "AnObjectContainingVcpkgArtifactsMetadata": "an object containing vcpkg-artifacts metadata",
   "_AnObjectContainingVcpkgArtifactsMetadata.comment": "'vcpkg-artifacts' is the name of the product feature and should not be localized",
   "AnOverlayPath": "an overlay path",

src/vcpkg/base/files.cpp

@@ -1755,6 +1755,18 @@ namespace vcpkg
         return result;
     }
 
+    int64_t ReadOnlyFilesystem::last_write_time(const Path& target, LineInfo li) const noexcept
+    {
+        std::error_code ec;
+        auto result = this->last_write_time(target, ec);
+        if (ec)
+        {
+            exit_filesystem_call_error(li, ec, __func__, {target});
+        }
+
+        return result;
+    }
+
     Path ReadOnlyFilesystem::almost_canonical(const Path& target, LineInfo li) const
     {
         std::error_code ec;
@@ -2849,6 +2861,28 @@ namespace vcpkg
 #endif // ^^^ !_WIN32
         }
 
+        virtual int64_t last_write_time(const Path& target, std::error_code& ec) const override
+        {
+#if defined(_WIN32)
+            auto result = stdfs::last_write_time(to_stdfs_path(target), ec);
+            return result.time_since_epoch().count();
+#else // ^^^ _WIN32 // !_WIN32 vvv
+            struct stat s;
+            if (::lstat(target.c_str(), &s) == 0)
+            {
+                ec.clear();
+#ifdef __APPLE__
+                return s.st_mtimespec.tv_sec * 1'000'000'000 + s.st_mtimespec.tv_nsec;
+#else
+                return s.st_mtim.tv_sec * 1'000'000'000 + s.st_mtim.tv_nsec;
+#endif
+            }
+
+            ec.assign(errno, std::generic_category());
+            return {};
+#endif // ^^^ !_WIN32
+        }
+
         virtual Path absolute(const Path& target, std::error_code& ec) const override
         {
 #if defined(_WIN32)

src/vcpkg/base/json.cpp

@@ -1048,6 +1048,10 @@ namespace vcpkg::Json
 
     const NaturalNumberDeserializer NaturalNumberDeserializer::instance;
 
+    LocalizedString Int64Deserializer::type_name() const { return msg::format(msgAnInt64); }
+
+    Int64Deserializer Int64Deserializer::instance;
+
     LocalizedString BooleanDeserializer::type_name() const { return msg::format(msgABoolean); }
 
     Optional<bool> BooleanDeserializer::visit_boolean(Reader&, bool b) const { return b; }