[vcpkg] Initial Registries: Part 2 MVP (#14153)

* [vcpkg wip] start implementation of registries pt. 2

* Remove the `ports` field of `VcpkgPaths`

This is an implementation detail, and so we want to make sure that
it's obvious that this is an internal detail; thus, we add a new function
`builtin_ports_directory()`,
which returns the directory where the builtin ports backing store is.

* continue WIP

* wip

* It works!

* format

* fix some issues

* switch from function static to DelayedInit
* fix lexically_normal for experimental::filesystem

* format

* fix missing include

* add STL notice

* whee error handling

* moar error handling!

* ignore extra files in registries

* formatting

* Billy CRs

* Update toolsrc/include/vcpkg/versiont.h

* fix add_filename test

* fix tests

* remove unused function add_filename

10 files changed, 87 insertions, 14 deletions

diff --git a/toolsrc/include/vcpkg/base/delayed_init.h b/toolsrc/include/vcpkg/base/delayed_init.h
new file mode 100644
index 000000000..a3257f54e
--- /dev/null
+++ b/toolsrc/include/vcpkg/base/delayed_init.h
@@ -0,0 +1,29 @@
+#pragma once
+
+#include <vcpkg/base/optional.h>
+
+#include <memory>
+#include <mutex>
+
+namespace vcpkg
+{
+    // implements the equivalent of function static initialization for an object
+    template<class T>
+    struct DelayedInit
+    {
+        template<class F>
+        const T& get(F&& f) const
+        {
+            std::call_once(underlying_->flag_, [&f, this]() { underlying_->storage_ = std::forward<F>(f)(); });
+            return *underlying_->storage_.get();
+        }
+
+    private:
+        struct Storage
+        {
+            std::once_flag flag_;
+            Optional<T> storage_;
+        };
+        std::unique_ptr<Storage> underlying_ = std::make_unique<Storage>();
+    };
+}
diff --git a/toolsrc/include/vcpkg/base/files.h b/toolsrc/include/vcpkg/base/files.h
index 1c5e8393f..3e56101c9 100644
--- a/toolsrc/include/vcpkg/base/files.h
+++ b/toolsrc/include/vcpkg/base/files.h
@@ -38,6 +38,7 @@ namespace fs
 
     path u8path(vcpkg::StringView s);
     inline path u8path(const char* first, const char* last) { return u8path(vcpkg::StringView{first, last}); }
+    inline path u8path(std::initializer_list<char> il) { return u8path(vcpkg::StringView{il.begin(), il.end()}); }
     inline path u8path(const char* s) { return u8path(vcpkg::StringView{s, s + ::strlen(s)}); }
 
 #if defined(_MSC_VER)
@@ -58,6 +59,9 @@ namespace fs
     std::string u8string(const path& p);
     std::string generic_u8string(const path& p);
 
+    // equivalent to p.lexically_normal()
+    path lexically_normal(const path& p);
+
 #if defined(_WIN32)
     enum class file_type
     {
@@ -251,9 +255,6 @@ namespace vcpkg::Files
     constexpr char preferred_separator = '/';
 #endif // _WIN32
 
-    // Adds file as a new path element to the end of base, with an additional slash if necessary
-    std::string add_filename(StringView base, StringView file);
-
 #if defined(_WIN32)
     fs::path win32_fix_path_case(const fs::path& source);
 #endif // _WIN32
diff --git a/toolsrc/include/vcpkg/base/jsonreader.h b/toolsrc/include/vcpkg/base/jsonreader.h
index 6518501a2..cdd0299d2 100644
--- a/toolsrc/include/vcpkg/base/jsonreader.h
+++ b/toolsrc/include/vcpkg/base/jsonreader.h
@@ -112,6 +112,24 @@ namespace vcpkg::Json
             m_path.pop_back();
         }
 
+        // value should be the value at key of the currently visited object
+        template<class Type>
+        void visit_at_index(const Value& value, int64_t index, Type& place, IDeserializer<Type>& visitor)
+        {
+            m_path.push_back(index);
+            auto opt = visitor.visit(*this, value);
+
+            if (auto p_opt = opt.get())
+            {
+                place = std::move(*p_opt);
+            }
+            else
+            {
+                add_expected_type_error(visitor.type_name());
+            }
+            m_path.pop_back();
+        }
+
         // returns whether key \in obj
         template<class Type>
         bool optional_object_field(const Object& obj, StringView key, Type& place, IDeserializer<Type>& visitor)
@@ -167,8 +185,8 @@ namespace vcpkg::Json
         }
     };
 
-    VCPKG_MSVC_WARNING(push);
-    VCPKG_MSVC_WARNING(disable : 4505);
+    VCPKG_MSVC_WARNING(push)
+    VCPKG_MSVC_WARNING(disable : 4505)
 
     template<class Type>
     Optional<Type> IDeserializer<Type>::visit(Reader& r, const Value& value)
@@ -235,7 +253,7 @@ namespace vcpkg::Json
         return nullopt;
     }
 
-    VCPKG_MSVC_WARNING(pop);
+    VCPKG_MSVC_WARNING(pop)
 
     struct StringDeserializer final : IDeserializer<std::string>
     {
diff --git a/toolsrc/include/vcpkg/base/optional.h b/toolsrc/include/vcpkg/base/optional.h
index 606d60ce5..c46c2e6f8 100644
--- a/toolsrc/include/vcpkg/base/optional.h
+++ b/toolsrc/include/vcpkg/base/optional.h
@@ -30,7 +30,7 @@ namespace vcpkg
             constexpr OptionalStorage(const T& t) : m_is_present(true), m_t(t) { }
             constexpr OptionalStorage(T&& t) : m_is_present(true), m_t(std::move(t)) { }
             template<class U, class = std::enable_if_t<!std::is_reference<U>::value>>
-            constexpr explicit OptionalStorage(Optional<U>&& t) : m_is_present(false), m_inactive()
+            explicit OptionalStorage(Optional<U>&& t) : m_is_present(false), m_inactive()
             {
                 if (auto p = t.get())
                 {
@@ -39,7 +39,7 @@ namespace vcpkg
                 }
             }
             template<class U>
-            constexpr explicit OptionalStorage(const Optional<U>& t) : m_is_present(false), m_inactive()
+            explicit OptionalStorage(const Optional<U>& t) : m_is_present(false), m_inactive()
             {
                 if (auto p = t.get())
                 {
diff --git a/toolsrc/include/vcpkg/base/pragmas.h b/toolsrc/include/vcpkg/base/pragmas.h
index 73f14c4b2..06efd5105 100644
--- a/toolsrc/include/vcpkg/base/pragmas.h
+++ b/toolsrc/include/vcpkg/base/pragmas.h
@@ -25,6 +25,7 @@
 #define ASSUME(expr)
 #endif
 
+// the static_assert(true, "")s are to avoid the extra ';' warning
 #ifdef _MSC_VER
 #define VCPKG_MSVC_WARNING(...) __pragma(warning(__VA_ARGS__))
 #define GCC_DIAGNOSTIC(...)
diff --git a/toolsrc/include/vcpkg/configurationdeserializer.h b/toolsrc/include/vcpkg/configurationdeserializer.h
index 83d3d0869..d6b239356 100644
--- a/toolsrc/include/vcpkg/configurationdeserializer.h
+++ b/toolsrc/include/vcpkg/configurationdeserializer.h
@@ -21,7 +21,7 @@ namespace vcpkg
         constexpr static StringLiteral PATH = "path";
 
         constexpr static StringLiteral KIND_BUILTIN = "builtin";
-        constexpr static StringLiteral KIND_DIRECTORY = "directory";
+        constexpr static StringLiteral KIND_FILESYSTEM = "filesystem";
 
         virtual StringView type_name() const override;
         virtual View<StringView> valid_fields() const override;
diff --git a/toolsrc/include/vcpkg/dependencies.h b/toolsrc/include/vcpkg/dependencies.h
index db135aa28..5e46a6194 100644
--- a/toolsrc/include/vcpkg/dependencies.h
+++ b/toolsrc/include/vcpkg/dependencies.h
@@ -172,7 +172,5 @@ namespace vcpkg::Dependencies
                                                            std::vector<std::string> features,
                                                            CMakeVars::CMakeVarProvider& var_provider);
 
-    void print_plan(const ActionPlan& action_plan,
-                    const bool is_recursive = true,
-                    const fs::path& default_ports_dir = {});
+    void print_plan(const ActionPlan& action_plan, const bool is_recursive = true, const fs::path& vcpkg_root_dir = {});
 }
diff --git a/toolsrc/include/vcpkg/registries.h b/toolsrc/include/vcpkg/registries.h
index 812bce86b..1f8c0f393 100644
--- a/toolsrc/include/vcpkg/registries.h
+++ b/toolsrc/include/vcpkg/registries.h
@@ -6,6 +6,8 @@
 #include <vcpkg/base/stringview.h>
 #include <vcpkg/base/view.h>
 
+#include <vcpkg/versiont.h>
+
 #include <memory>
 #include <string>
 #include <system_error>
@@ -13,9 +15,22 @@
 
 namespace vcpkg
 {
+    struct RegistryEntry
+    {
+        // returns fs::path() if version doesn't exist
+        virtual fs::path get_port_directory(const VcpkgPaths& paths, const VersionT& version) const = 0;
+
+        virtual ~RegistryEntry() = default;
+    };
+
     struct RegistryImpl
     {
-        virtual fs::path get_registry_root(const VcpkgPaths& paths) const = 0;
+        // returns nullptr if the port doesn't exist
+        virtual std::unique_ptr<RegistryEntry> get_port_entry(const VcpkgPaths& paths, StringView port_name) const = 0;
+        // appends the names of the ports to the out parameter
+        virtual void get_all_port_names(std::vector<std::string>& port_names, const VcpkgPaths& paths) const = 0;
+
+        virtual Optional<VersionT> get_baseline_version(const VcpkgPaths& paths, StringView port_name) const = 0;
 
         virtual ~RegistryImpl() = default;
     };
diff --git a/toolsrc/include/vcpkg/vcpkgpaths.h b/toolsrc/include/vcpkg/vcpkgpaths.h
index aa1ba92d7..def874e7c 100644
--- a/toolsrc/include/vcpkg/vcpkgpaths.h
+++ b/toolsrc/include/vcpkg/vcpkgpaths.h
@@ -86,7 +86,6 @@ namespace vcpkg
         fs::path buildtrees;
         fs::path downloads;
         fs::path packages;
-        fs::path ports;
         fs::path installed;
         fs::path triplets;
         fs::path community_triplets;
@@ -128,6 +127,10 @@ namespace vcpkg
         const FeatureFlagSettings& get_feature_flags() const;
         void track_feature_flag_metrics() const;
 
+        // the directory of the builtin ports
+        // this should be used only for helper commands, not core commands like `install`.
+        fs::path builtin_ports_directory() const { return root / fs::u8path("ports"); }
+
     private:
         std::unique_ptr<details::VcpkgPathsImpl> m_pimpl;
     };
diff --git a/toolsrc/include/vcpkg/versiont.h b/toolsrc/include/vcpkg/versiont.h
index 768ca0c47..506d7090a 100644
--- a/toolsrc/include/vcpkg/versiont.h
+++ b/toolsrc/include/vcpkg/versiont.h
@@ -1,4 +1,5 @@
 #pragma once
+
 #include <string>
 
 namespace vcpkg
@@ -14,6 +15,8 @@ namespace vcpkg
         friend bool operator==(const VersionT& left, const VersionT& right);
         friend bool operator!=(const VersionT& left, const VersionT& right);
 
+        friend struct VersionTMapLess;
+
     private:
         std::string value;
         int port_version;
@@ -29,4 +32,9 @@ namespace vcpkg
 
         std::string to_string() const;
     };
+
+    struct VersionTMapLess
+    {
+        bool operator()(const VersionT& left, const VersionT& right) const;
+    };
 }