Hello libcode-seafire-common

.editorconfig

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+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+indent_size = 4
+max_line_length = off
+trim_trailing_whitespace = false
+
+[*.yaml]
+indent_size = 2

.gitattributes

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+* text=auto

.gitea/workflows/on-push.yaml

@@ -0,0 +1,24 @@
+name: on-push
+on: [push]
+
+jobs:
+  build-and-test:
+    runs-on: linux
+    container: code.helloryan.se/infra/buildenv/cxx-amd64-fedora-40:latest
+    volumes:
+      - /build
+    steps:
+      - name: Clone repository
+        uses: actions/checkout@v3
+      - name: Authenticate
+        run: |
+          git config unset http.https://code.helloryan.se/.extraheader
+          echo "${{ secrets.NETRC }}" >> ~/.netrc
+      - name: Initialize
+        run: |
+          bpkg create -d /build cc config.cc.coptions="-Wall -Werror"
+          bdep init -A /build
+      - name: Build
+        run: b
+      - name: Test
+        run: b test

.gitignore

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+.bdep/
+Doxyfile
+
+# Local default options files.
+#
+.build2/local/
+
+# Compiler/linker output.
+#
+*.d
+*.t
+*.i
+*.i.*
+*.ii
+*.ii.*
+*.o
+*.obj
+*.gcm
+*.pcm
+*.ifc
+*.so
+*.dylib
+*.dll
+*.a
+*.lib
+*.exp
+*.pdb
+*.ilk
+*.exe
+*.exe.dlls/
+*.exe.manifest
+*.pc

LICENSE

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+Copyright © 2024 Ryan. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+3. All advertising materials mentioning features or use of this software must
+   display the following acknowledgement:
+
+       This product includes software developed by Ryan, http://helloryan.se/.
+
+4. Neither the name(s) of the copyright holder(s) nor the names of its
+   contributors may be used to endorse or promote products derived from this
+   software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY COPYRIGHT HOLDER "AS IS" AND ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
+NO EVENT SHALL COPYRIGHT HOLDER BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+# libcode-seafire-common
+
+![Build status](https://code.helloryan.se/code/libcode-seafire-common/actions/workflows/on-push.yaml/badge.svg)
+
+## Requirements
+
+None, other than a modern C++-compiler.
+
+## Building
+
+See the wiki, https://code.helloryan.se/code/wiki/wiki/Build-Instructions, for
+build instructions.
+
+## Contact
+
+Please report bugs and issues by sending an e-mail to: ryan@helloryan.se.
+
+## Contributing
+
+Please send an e-mail to ryan@helloryan.se to request an account and
+write-access to the libcode-seafire-common repository.

build/.gitignore

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+/config.build
+/root/
+/bootstrap/
+build/

build/bootstrap.build

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+project = libcode-seafire-common
+
+using version
+using config
+using test
+using install
+using dist

build/export.build

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+$out_root/
+{
+  include code/seafire/common/
+}
+
+export $out_root/code/seafire/common/$import.target

build/root.build

@@ -0,0 +1,16 @@
+# Uncomment to suppress warnings coming from external libraries.
+#
+#cxx.internal.scope = current
+
+cxx.std = latest
+
+using cxx
+
+hxx{*}: extension = hxx
+ixx{*}: extension = ixx
+txx{*}: extension = txx
+cxx{*}: extension = cxx
+
+# The test target for cross-testing (running tests under Wine, etc).
+#
+test.target = $cxx.target

buildfile

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+./: {code/ tests/} doc{README.md} legal{LICENSE} manifest
+
+# Don't install tests.
+#
+tests/: install = false

code/seafire/common/.gitignore

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+# Generated version header.
+#
+version.hxx
+
+# Unit test executables and Testscript output directories
+# (can be symlinks).
+#
+*.test
+test-*.test

code/seafire/common/allocator.cxx

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+#include <code/seafire/common/allocator.hxx>
+
+namespace code::seafire::common
+{
+
+  allocator_t::
+  allocator_t() = default;
+
+  allocator_t::allocation_t::
+  allocation_t() = default;
+
+  allocator_t::allocation_t::
+  ~allocation_t() noexcept = default;
+
+} // namespace code::seafire::common

code/seafire/common/allocator.hxx

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+#ifndef code__seafire__common__allocator_hxx_
+#define code__seafire__common__allocator_hxx_
+
+#include <memory>
+#include <set>
+
+namespace code::seafire::common
+{
+
+  /// Implements a memory allocator keeping track of allocations.
+  ///
+  /// All allocations made through an allocator_t are valid for the
+  /// lifetime of the allocator_t object.
+  ///
+  class allocator_t
+  {
+  public:
+    allocator_t();
+
+    allocator_t(allocator_t const&) = delete;
+    allocator_t(allocator_t&&) = delete;
+
+    template<typename T>
+    T&
+    alloc();
+
+    template<typename T>
+    T&
+    alloc(T const&);
+
+    template<typename T>
+    T&
+    alloc(T&&);
+
+    template<typename T, typename... Args>
+    T&
+    alloc_emplace(Args&&...);
+
+    allocator_t& operator=(allocator_t const&) = delete;
+    allocator_t& operator=(allocator_t&&) = delete;
+
+  private:
+    struct allocation_t
+    {
+      allocation_t();
+
+      allocation_t(allocation_t const&) = delete;
+      allocation_t(allocation_t&&) = delete;
+
+      virtual
+      ~allocation_t() noexcept;
+
+      allocation_t& operator=(allocation_t const&) = delete;
+      allocation_t& operator=(allocation_t&&) = delete;
+
+    };
+
+    std::set<std::unique_ptr<allocation_t>> allocations_;
+
+  };
+
+} // namespace code::seafire::common
+
+#include <code/seafire/common/allocator.txx>
+
+#endif

code/seafire/common/allocator.txx

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+namespace code::seafire::common
+{
+
+  template<typename T>
+  T&
+  allocator_t::
+  alloc()
+  {
+    return alloc_emplace<T>();
+  }
+
+  template<typename T>
+  T&
+  allocator_t::
+  alloc(T const& object)
+  {
+    return alloc_emplace<T>(object);
+  }
+
+  template<typename T>
+  T&
+  allocator_t::
+  alloc(T&& object)
+  {
+    return alloc_emplace<T>(object);
+  }
+
+  template<typename T, typename... Args>
+  T&
+  allocator_t::
+  alloc_emplace(Args&&... args)
+  {
+    struct object_t
+      : allocation_t
+    {
+      object_t(Args&&... args)
+        : object{std::forward<Args>(args)...}
+      {}
+
+      T object;
+
+    };
+
+    std::unique_ptr<object_t> a{
+      new object_t{std::forward<Args>(args)...}
+    };
+
+    auto& ref = a->object;
+
+    allocations_.emplace(std::move(a));
+
+    return ref;
+  }
+
+} // namespace code::seafire::common

code/seafire/common/buildfile

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+intf_libs = # Interface dependencies.
+impl_libs = # Implementation dependencies.
+
+import intf_libs =+ libasio%lib{asio}
+
+./: lib{code-seafire-common}: libul{code-seafire-common}
+
+libul{code-seafire-common}: {hxx ixx txx cxx}{** -**.test... -version} \
+                            {hxx            }{                version}
+
+libul{code-seafire-common}: $impl_libs $intf_libs
+
+# Unit tests.
+#
+exe{*.test}:
+{
+  test = true
+  install = false
+}
+
+for t: cxx{**.test...}
+{
+  d = $directory($t)
+  n = $name($t)...
+
+  ./: $d/exe{$n}: $t $d/{hxx ixx txx}{+$n} $d/testscript{+$n}
+  $d/exe{$n}: libul{code-seafire-common}: bin.whole = false
+}
+
+hxx{version}: in{version} $src_root/manifest
+{
+  dist  = true
+  clean = ($src_root != $out_root)
+}
+
+# Build options.
+#
+cxx.poptions =+ "-I$out_root" "-I$src_root"
+cxx.coptions =+ -fvisibility=hidden
+
+# Export options.
+#
+lib{code-seafire-common}:
+{
+  cxx.export.poptions = "-I$out_root" "-I$src_root"
+  cxx.export.libs = $intf_libs
+}
+
+# For pre-releases use the complete version to make sure they cannot
+# be used in place of another pre-release or the final version. See
+# the version module for details on the version.* variable values.
+#
+if $version.pre_release
+  lib{code-seafire-common}: bin.lib.version = "-$version.project_id"
+else
+  lib{code-seafire-common}: bin.lib.version = "-$version.major.$version.minor"
+
+# Install into the code/seafire/common/ subdirectory of, say, /usr/include/
+# recreating subdirectories.
+#
+{hxx ixx txx}{*}:
+{
+  install         = include/code/seafire/common/
+  install.subdirs = true
+}

code/seafire/common/diagnostics.cxx

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+#include <code/seafire/common/diagnostics.hxx>
+
+#include <iomanip>
+
+namespace code::seafire::common
+{
+
+  void
+  diagnostics_t::
+  enable(category_t const& category)
+  {
+    categories_.emplace(&category);
+  }
+
+  void
+  diagnostics_t::
+  disable(category_t const& category)
+  {
+    categories_.erase(&category);
+  }
+
+  diagnostics_t::proxy_t
+  diagnostics_t::
+  operator<<(category_t const& category)
+  {
+    return proxy_t{*this, category};
+  }
+
+  diagnostics_t::
+  diagnostics_t() = default;
+
+  diagnostics_t::
+  ~diagnostics_t() noexcept = default;
+
+  bool
+  diagnostics_t::
+  is_enabled(category_t const& category)
+  {
+    return categories_.count(&category) == 1;
+  }
+
+  void
+  diagnostics_t::
+  log(record_t record)
+  {
+    if (!is_enabled(record.category)) {
+      return;
+    }
+
+    std::size_t max{0};
+
+    for (auto const& j : categories_) {
+      if (auto size = j->prefix().size(); size > max) {
+        max = size;
+      }
+    }
+
+    std::stringstream message;
+
+    for (std::string line; std::getline(record.message, line);) {
+      message << " -> "
+              << std::left
+              << std::setw(max)
+              << record.category.prefix()
+              << ": "
+              << line
+              << '\n';
+    }
+
+    do_log(message.str());
+  }
+
+  diagnostics_t::category_t::
+  category_t(std::string prefix)
+    : prefix_{std::move(prefix)}
+  {}
+
+  diagnostics_t::category_t::
+  ~category_t() noexcept = default;
+
+  std::string const&
+  diagnostics_t::category_t::
+  prefix() const
+  {
+    return prefix_;
+  }
+
+  diagnostics_t::proxy_t::
+  ~proxy_t() noexcept
+  {
+    if (diagnostics_) {
+      diagnostics_->log({category_, std::move(message_)});
+    }
+  }
+
+  diagnostics_t::proxy_t::
+  proxy_t(diagnostics_t& diagnostics, category_t const& category)
+    : diagnostics_{&diagnostics},
+      category_{category}
+  {}
+
+  diagnostics_t::proxy_t::
+  proxy_t(proxy_t&& other) noexcept
+    : category_{other.category_}
+  {
+    std::swap(diagnostics_, other.diagnostics_);
+  }
+
+  ostream_diagnostics_t::
+  ostream_diagnostics_t(std::ostream& output)
+    : output_{output}
+  {}
+
+  ostream_diagnostics_t::
+  ~ostream_diagnostics_t() noexcept = default;
+
+  std::ostream&
+  ostream_diagnostics_t::
+  output()
+  {
+    return output_;
+  }
+
+  void
+  ostream_diagnostics_t::
+  do_log(std::string const& message)
+  {
+    output() << message;
+  }
+
+
+} // namespace code::seafire::common

code/seafire/common/diagnostics.hxx

@@ -0,0 +1,160 @@
+#ifndef code__seafire__common__diagnostics_hxx_
+#define code__seafire__common__diagnostics_hxx_
+
+#include <ostream>
+#include <set>
+#include <sstream>
+#include <string>
+
+namespace code::seafire::common
+{
+
+  /// Provides a base for implementing diagnostics.
+  ///
+  class diagnostics_t
+  {
+  public:
+    class category_t;
+    class proxy_t;
+
+    friend proxy_t;
+
+    void
+    enable(category_t const&);
+
+    void
+    disable(category_t const&);
+
+    proxy_t
+    operator<<(category_t const&);
+
+  protected:
+    struct record_t;
+
+    diagnostics_t();
+
+    diagnostics_t(diagnostics_t const&) = delete;
+    diagnostics_t(diagnostics_t&&) = delete;
+
+    ~diagnostics_t() noexcept;
+
+    bool
+    is_enabled(category_t const&);
+
+    void
+    log(record_t);
+
+    virtual
+    void
+    do_log(std::string const&) = 0;
+
+    diagnostics_t& operator=(diagnostics_t const&) = delete;
+    diagnostics_t& operator=(diagnostics_t&&) = delete;
+
+  private:
+    std::set<category_t const*> categories_;
+
+  };
+
+  /// Represents a diagnostic category.
+  ///
+  class diagnostics_t::category_t
+  {
+  public:
+    explicit
+    category_t(std::string);
+
+    category_t(category_t const&) = delete;
+    category_t(category_t&&) = delete;
+
+    ~category_t() noexcept;
+
+    std::string const&
+    prefix() const;
+
+    category_t& operator=(category_t const&) = delete;
+    category_t& operator=(category_t&&) = delete;
+
+  private:
+    std::string prefix_;
+
+  };
+
+  /// Proxy for writing diagnostics.
+  ///
+  class diagnostics_t::proxy_t
+  {
+  public:
+    ~proxy_t() noexcept;
+
+    template<typename T>
+    proxy_t&
+    operator<<(T const& other)
+    {
+      message_ << other;
+      return *this;
+    }
+
+  protected:
+    friend diagnostics_t;
+
+    proxy_t(diagnostics_t&, category_t const&);
+
+    proxy_t(proxy_t const&) = delete;
+
+    proxy_t(proxy_t&&) noexcept;
+
+    proxy_t& operator=(proxy_t const&) = delete;
+    proxy_t& operator=(proxy_t&&) = delete;
+
+  private:
+    diagnostics_t* diagnostics_{};
+    category_t const& category_;
+    std::stringstream message_;
+
+  };
+
+  /// Represents a diagnostic record.
+  ///
+  struct diagnostics_t::record_t
+  {
+    /// The diagnostic category.
+    ///
+    category_t const& category;
+
+    /// The diagnostic message.
+    ///
+    std::stringstream message;
+
+  };
+
+  class ostream_diagnostics_t
+    : public diagnostics_t
+  {
+  public:
+    explicit
+    ostream_diagnostics_t(std::ostream&);
+
+    ostream_diagnostics_t(ostream_diagnostics_t const&) = delete;
+    ostream_diagnostics_t(ostream_diagnostics_t&&) = delete;
+
+    ~ostream_diagnostics_t() noexcept;
+
+    std::ostream&
+    output();
+
+    ostream_diagnostics_t& operator=(ostream_diagnostics_t const&) = delete;
+    ostream_diagnostics_t& operator=(ostream_diagnostics_t&&) = delete;
+
+  protected:
+    void
+    do_log(std::string const&) override;
+
+  private:
+    std::ostream& output_;
+
+  };
+
+} // namespace code::seafire::common
+
+#endif

code/seafire/common/extension-context.cxx

@@ -0,0 +1,48 @@
+#include <code/seafire/common/extension-context.hxx>
+
+namespace code::seafire::common
+{
+
+  void*
+  extension_context_t::
+  use(std::type_index const& key) const
+  {
+    auto it = extensions_.find(key);
+
+    if (it == extensions_.end())
+      throw extension_not_found_t{};
+
+    return it->second;
+  }
+
+  void
+  extension_context_t::
+  extend(std::type_index const& key, void* ptr)
+  {
+    if (0 != extensions_.count(key))
+      throw duplicate_extension_t{};
+
+    if (!ptr)
+      throw std::invalid_argument{"invalid pointer"};
+
+    extensions_.emplace(key, ptr);
+  }
+
+  void
+  extension_context_t::
+  erase_extension(std::type_index const& key)
+  {
+    extensions_.erase(key);
+  }
+
+  extension_not_found_t::
+  extension_not_found_t()
+    : std::runtime_error{"extension not found"}
+  {}
+
+  duplicate_extension_t::
+  duplicate_extension_t()
+    : std::runtime_error{"extension already registered"}
+  {}
+
+} // namespace code::seafire::common

code/seafire/common/extension-context.hxx

@@ -0,0 +1,91 @@
+#ifndef code__seafire__common__extension_context_hxx_
+#define code__seafire__common__extension_context_hxx_
+
+#include <map>
+#include <stdexcept>
+#include <typeindex>
+
+namespace code::seafire::common
+{
+
+  /// Implements a context tracking extensions.
+  ///
+  /// Ownership of registered extensions is not assumed.
+  ///
+  class extension_context_t
+  {
+  public:
+    template<typename E>
+    E&
+    use();
+
+    template<typename E>
+    E const&
+    use() const;
+
+    template<typename E>
+    void
+    extend(E* ptr);
+
+    template<typename E>
+    void
+    erase();
+
+  private:
+    void*
+    use(std::type_index const& key) const;
+
+    void
+    extend(std::type_index const& key, void* ptr);
+
+    void
+    erase_extension(std::type_index const& key);
+
+    std::map<std::type_index, void*> extensions_;
+
+  };
+
+  class extension_not_found_t
+    : public std::runtime_error
+  {
+  public:
+    extension_not_found_t();
+
+  };
+
+  class duplicate_extension_t
+    : public std::runtime_error
+  {
+  public:
+    duplicate_extension_t();
+
+  };
+
+  /// Provides extending an extension context using RAII.
+  ///
+  template<typename E>
+  class extend_t
+  {
+  public:
+    using extension_type = typename std::decay_t<E>;
+
+    extend_t(extension_context_t&, extension_type&);
+
+    extend_t(extend_t const&) = delete;
+    extend_t(extend_t&&) = delete;
+
+    ~extend_t() noexcept;
+
+    extend_t& operator=(extend_t const&) = delete;
+    extend_t& operator=(extend_t&&) = delete;
+
+  private:
+    extension_context_t& target_;
+
+  };
+
+} // namespace code::seafire::common
+
+#include <code/seafire/common/extension-context.txx>
+
+#endif

code/seafire/common/extension-context.txx

@@ -0,0 +1,63 @@
+namespace code::seafire::common
+{
+
+  /// Use an extension of type E.
+  ///
+  template<typename E>
+  E&
+  extension_context_t::
+  use()
+  {
+    static std::type_index const key{typeid(E)};
+    return *(static_cast<E*>(use(key)));
+  }
+
+  /// Use an extension of type E.
+  ///
+  template<typename E>
+  E const&
+  extension_context_t::
+  use() const
+  {
+    static std::type_index const key{typeid(E)};
+    return *(static_cast<E*>(use(key)));
+  }
+
+  /// Add an extension to this context.
+  ///
+  template<typename E>
+  void
+  extension_context_t::
+  extend(E* ptr)
+  {
+    static std::type_index const key{typeid(E)};
+    extend(key, ptr);
+  }
+
+  /// Erase an extension from this context.
+  ///
+  template<typename E>
+  void
+  extension_context_t::
+  erase()
+  {
+    static std::type_index const key{typeid(E)};
+    erase_extension(key);
+  }
+
+  template<typename E>
+  extend_t<E>::
+  extend_t(extension_context_t& target, extension_type& ext)
+    : target_{target}
+  {
+    target.extend(&ext);
+  }
+
+  template<typename E>
+  extend_t<E>::
+  ~extend_t() noexcept
+  {
+    target_.erase<extension_type>();
+  }
+
+} // namespace code::seafire::common

code/seafire/common/invoke.hxx

@@ -0,0 +1,54 @@
+#ifndef code__seafire__common__invoke_hxx_
+#define code__seafire__common__invoke_hxx_
+
+#include <code/seafire/server/request.hxx>
+#include <code/seafire/server/response.hxx>
+
+namespace code::seafire::common
+{
+
+  template<typename Ret, typename T, typename... Direct, typename... Params>
+  Ret
+  do_invoke(T& target,
+            server::request_t& req,
+            Direct const&... direct,
+            Ret (T::*func)(Direct const&..., Params const&...));
+
+  template<typename Ret, typename T, typename... Params, typename... Direct>
+  Ret
+  invoke(T& target,
+         server::request_t& req,
+         Ret (T::*func)(Params const&...),
+         Direct const&... direct);
+
+  template<typename Ret, typename T, typename... Direct, typename... Params>
+  Ret
+  do_invoke(T const& target,
+            server::request_t& req,
+            Direct const&... direct,
+            Ret (T::*func)(Direct const&..., Params const&...) const);
+
+  template<typename Ret, typename T, typename... Params, typename... Direct>
+  Ret
+  invoke(T const& target,
+         server::request_t& req,
+         Ret (T::*func)(Params const&...) const,
+         Direct const&... direct);
+
+  template<typename Ret, typename... Direct, typename... Params>
+  Ret
+  do_invoke(server::request_t& req,
+            Direct&&... direct,
+            Ret (*func)(Direct..., Params...));
+
+  template<typename Ret, typename... Params, typename... Direct>
+  Ret
+  invoke(server::request_t& req,
+         Ret (*func)(Params...),
+         Direct&&... direct);
+
+} // namespace code::seafire::common
+
+#include <code/seafire/common/invoke.txx>
+
+#endif

code/seafire/common/invoke.txx

@@ -0,0 +1,62 @@
+namespace code::seafire::common
+{
+
+  template<typename Ret, typename T, typename... Direct, typename... Params>
+  Ret
+  do_invoke(T& target,
+            server::request_t& req,
+            Direct const&... direct,
+            Ret (T::*func)(Direct const&..., Params const&...))
+  {
+    return (target.*func)(direct..., std::decay_t<Params>::fetch(req)...);
+  }
+
+  template<typename Ret, typename T, typename... Params, typename... Direct>
+  Ret
+  invoke(T& target,
+         server::request_t& req,
+         Ret (T::*func)(Params const&...),
+         Direct const&... direct)
+  {
+    return do_invoke<Ret, T, Direct...>(target, req, direct..., func);
+  }
+
+  template<typename Ret, typename T, typename... Direct, typename... Params>
+  Ret
+  do_invoke(T const& target,
+            server::request_t& req,
+            Direct const&... direct,
+            Ret (T::*func)(Direct const&..., Params const&...) const)
+  {
+    return (target.*func)(direct..., std::decay_t<Params>::fetch(req)...);
+  }
+
+  template<typename Ret, typename T, typename... Params, typename... Direct>
+  Ret
+  invoke(T const& target,
+         server::request_t& req,
+         Ret (T::*func)(Params const&...) const,
+         Direct const&... direct)
+  {
+    return do_invoke<Ret, T, Direct...>(target, req, direct..., func);
+  }
+
+  template<typename Ret, typename... Direct, typename... Params>
+  Ret
+  do_invoke(server::request_t& req,
+            Direct&&... direct,
+            Ret (*func)(Direct..., Params...))
+  {
+    return (*func)(direct..., std::decay_t<Params>::fetch(req)...);
+  }
+
+  template<typename Ret, typename... Params, typename... Direct>
+  Ret
+  invoke(server::request_t& req,
+         Ret (*func)(Params...),
+         Direct&&... direct)
+  {
+    return do_invoke<Ret, Direct...>(req, direct..., func);
+  }
+
+} // namespace code::seafire::common

code/seafire/common/io/acceptor.cxx

@@ -0,0 +1,12 @@
+#include <code/seafire/common/io/acceptor.hxx>
+
+namespace code::seafire::common::io
+{
+
+  acceptor_t::
+  ~acceptor_t() noexcept = default;
+
+  acceptor_t::
+  acceptor_t() = default;
+
+} // namespace code::seafire::common::io

code/seafire/common/io/acceptor.hxx

@@ -0,0 +1,51 @@
+#ifndef code__seafire__common__io__acceptor_hxx_
+#define code__seafire__common__io__acceptor_hxx_
+
+#include <code/seafire/common/io/stream.hxx>
+
+#include <asio.hpp>
+
+#include <functional>
+#include <memory>
+
+namespace code::seafire::common::io
+{
+
+  /// Abstract base class for acceptors.
+  ///
+  class acceptor_t
+  {
+  public:
+    /// Non-blocking accept handler type.
+    ///
+    using accept_handler_t = std::function<
+      void(std::error_code, std::unique_ptr<stream_t>)
+    >;
+
+    virtual
+    ~acceptor_t() noexcept;
+
+    virtual
+    asio::any_io_executor const&
+    get_executor() = 0;
+
+    /// Initiate a non-blocking accept of a new stream.
+    ///
+    virtual
+    void
+    async_accept(accept_handler_t) = 0;
+
+  protected:
+    acceptor_t();
+
+    acceptor_t(acceptor_t const&) = delete;
+    acceptor_t(acceptor_t&&) = delete;
+
+    acceptor_t& operator=(acceptor_t const&) = delete;
+    acceptor_t& operator=(acceptor_t&&) = delete;
+
+  };
+
+} // namespace code::seafire::common::io
+
+#endif

code/seafire/common/io/buffer.hxx

@@ -0,0 +1,23 @@
+#ifndef code__seafire__common__io__buffer_hxx_
+#define code__seafire__common__io__buffer_hxx_
+
+#include <asio.hpp>
+
+#include <vector>
+
+namespace code::seafire::common::io
+{
+
+  using const_buffer_t = asio::const_buffer;
+  using const_buffers_t = std::vector<const_buffer_t>;
+
+  using mutable_buffer_t = asio::mutable_buffer;
+  using mutable_buffers_t = std::vector<mutable_buffer_t>;
+
+  using asio::buffer;
+  using asio::buffer_size;
+  using asio::buffer_copy;
+
+} // namespace code::seafire::common::io
+
+#endif

code/seafire/common/io/diagnostics.cxx

@@ -0,0 +1,13 @@
+#include <code/seafire/common/io/diagnostics.hxx>
+
+namespace code::seafire::common::io
+{
+
+  common::diagnostics_t::category_t const&
+  io_category()
+  {
+    static common::diagnostics_t::category_t category{"io"};
+    return category;
+  }
+
+} // namespace code::seafire::common::io

code/seafire/common/io/diagnostics.hxx

@@ -0,0 +1,14 @@
+#ifndef code__seafire__common__io_diagnostics_hxx_
+#define code__seafire__common__io_diagnostics_hxx_
+
+#include <code/seafire/common/diagnostics.hxx>
+
+namespace code::seafire::common::io
+{
+
+  common::diagnostics_t::category_t const&
+  io_category();
+
+} // namespace code::seafire::common::io
+
+#endif

code/seafire/common/io/error.cxx

@@ -0,0 +1,31 @@
+#include <code/seafire/common/io/error.hxx>
+
+namespace code::seafire::common::io
+{
+
+  std::error_code
+  make_error_code(error_t e)
+  {
+    static
+    struct : std::error_category
+    {
+      char const* name() const noexcept override
+      {
+        return "seafire.common.io";
+      }
+
+      std::string message(int e) const override
+      {
+        switch (static_cast<error_t>(e)) {
+          case error_t::unknown: return "unknown error";
+          case error_t::read_until_buffer_overflow: return "buffer overflow";
+        }
+
+        return "(unrecognized error)";
+      }
+    } category;
+
+    return {static_cast<int>(e), category};
+  }
+
+} // namespace code::seafire::common::io

code/seafire/common/io/error.hxx

@@ -0,0 +1,37 @@
+#ifndef code__seafire__common__io__error_hxx_
+#define code__seafire__common__io__error_hxx_
+
+#include <system_error>
+#include <type_traits>
+
+namespace code::seafire::common::io
+{
+
+  /// Common error codes.
+  ///
+  enum class error_t
+  {
+    /// Represents an unknown error.
+    ///
+    unknown = 1,
+
+    read_until_buffer_overflow
+
+  };
+
+  std::error_code
+  make_error_code(error_t);
+
+} // namespace code::seafire::common::io
+
+namespace std
+{
+
+  template<>
+  struct is_error_code_enum<::code::seafire::common::io::error_t>
+    : true_type
+  {};
+
+} // namespace std
+
+#endif

code/seafire/common/io/read-until.cxx

@@ -0,0 +1,131 @@
+#include <code/seafire/common/io/read-until.hxx>
+
+#include <code/seafire/common/io/error.hxx>
+
+namespace code::seafire::common::io
+{
+
+  std::size_t
+  read_until(stream_t& s, asio::streambuf& b, match_condition_t m)
+  {
+    std::error_code ec;
+    auto n = read_until(s, b, m, ec);
+
+    if (ec) {
+      throw std::system_error{ec};
+    }
+
+    return n;
+  }
+
+  std::size_t
+  read_until(stream_t& s,
+             asio::streambuf& b,
+             match_condition_t m,
+             std::error_code& ec)
+  {
+    for (;;) {
+      // search for a match.
+      //
+      auto begin = static_cast<char const*>(b.data().data());
+      auto result = m(begin, begin + b.data().size(), ec);
+
+      if (ec) {
+        return 0;
+      }
+
+      if (result.second) {
+        return result.first - begin;
+      }
+
+      // bail out if buffer is already full.
+      //
+      if (b.size() == b.max_size()) {
+        ec = make_error_code(error_t::read_until_buffer_overflow);
+        return 0;
+      }
+
+      // read more data.
+      //
+      auto bytes_to_read = std::min<std::size_t>(
+        std::max<std::size_t>(  512, b.capacity() - b.size()),
+        std::min<std::size_t>(65536, b.max_size() - b.size())
+      );
+
+      auto n = s.read(b.prepare(bytes_to_read), ec);
+      b.commit(n);
+
+      if (ec) {
+        return 0;
+      }
+    }
+  }
+
+  void
+  async_read_until(stream_t& s,
+                   asio::streambuf& b,
+                   match_condition_t m,
+                   read_until_handler_t h)
+  {
+    struct operation_t
+    {
+      stream_t& s;
+      asio::streambuf& b;
+      match_condition_t match;
+      read_until_handler_t handler;
+
+      void
+      operator()(std::error_code const& ec,
+                 std::size_t n,
+                 bool start = false)
+      {
+        if (ec || (!start && n == 0)) {
+          handler(ec, 0);
+          return;
+        }
+
+        b.commit(n);
+
+        // search for a match.
+        //
+        auto begin = static_cast<char const*>(b.data().data());
+
+        std::error_code match_ec;
+        auto result = match(begin, begin + b.data().size(), match_ec);
+
+        if (match_ec) {
+          handler(match_ec, 0);
+          return;
+        }
+
+        if (result.second) {
+          handler({}, result.first - begin);
+          return;
+        }
+
+        if (b.size() == b.max_size()) {
+          handler(make_error_code(error_t::read_until_buffer_overflow), 0);
+          return;
+        }
+
+        // read more data.
+        //
+        auto bytes_to_read = std::min<std::size_t>(
+          std::max<std::size_t>(  512, b.capacity() - b.size()),
+          std::min<std::size_t>(65536, b.max_size() - b.size())
+        );
+
+        s.async_read(b.prepare(bytes_to_read), std::move(*this));
+      }
+
+    };
+
+    auto init = [&s, &b, m, h]
+    {
+      operation_t{s, b, m, h}({}, 0, true);
+    };
+
+    asio::post(s.get_executor(), init);
+  }
+
+} // namespace code::seafire::common::io

code/seafire/common/io/read-until.hxx

@@ -0,0 +1,39 @@
+#ifndef code__seafire__common__io__read_until_hxx_
+#define code__seafire__common__io__read_until_hxx_
+
+#include <code/seafire/common/io/stream.hxx>
+
+#include <functional>
+#include <system_error>
+
+#include <asio.hpp>
+
+namespace code::seafire::common::io
+{
+
+  using match_condition_t = std::function<
+    std::pair<char const*, bool>(char const*, char const*, std::error_code&)
+  >;
+
+  using read_until_handler_t = std::function<
+    void(std::error_code, std::size_t)
+  >;
+
+  std::size_t
+  read_until(stream_t&, asio::streambuf&, match_condition_t);
+
+  std::size_t
+  read_until(stream_t&,
+             asio::streambuf&,
+             match_condition_t,
+             std::error_code&);
+
+  void
+  async_read_until(stream_t&,
+                   asio::streambuf&,
+                   match_condition_t,
+                   read_until_handler_t);
+
+} // namespace code::seafire::common::io
+
+#endif

code/seafire/common/io/stream.cxx

@@ -0,0 +1,12 @@
+#include <code/seafire/common/io/stream.hxx>
+
+namespace code::seafire::common::io
+{
+
+  stream_t::
+  ~stream_t() noexcept = default;
+
+  stream_t::
+  stream_t() = default;
+
+} // namespace code::seafire::common::io

code/seafire/common/io/stream.hxx

@@ -0,0 +1,137 @@
+#ifndef code__seafire__common__io__stream_hxx_
+#define code__seafire__common__io__stream_hxx_
+
+#include <code/seafire/common/io/buffer.hxx>
+
+#include <asio.hpp>
+
+#include <functional>
+#include <system_error>
+
+namespace code::seafire::common::io
+{
+
+  /// Abstract base class for stream.
+  ///
+  class stream_t
+  {
+  public:
+    /// Non-blocking read handler type.
+    ///
+    using read_handler_t = std::function<void(std::error_code, std::size_t)>;
+
+    /// Non-blocking write handler type.
+    ///
+    using write_handler_t = std::function<void(std::error_code, std::size_t)>;
+
+    /// Non-blocking graceful close handler type.
+    ///
+    using graceful_close_handler_t = std::function<void()>;
+
+    virtual
+    ~stream_t() noexcept;
+
+    /// Get the asio executor associated with this stream.
+    ///
+    virtual
+    asio::any_io_executor const&
+    get_executor() = 0;
+
+    /// Cancel any pending non-blocking operations.
+    ///
+    virtual
+    void
+    cancel() = 0;
+
+    /// Close this stream.
+    ///
+    virtual
+    void
+    close() = 0;
+
+    /// Close this stream.
+    ///
+    virtual
+    void
+    close(std::error_code&) = 0;
+
+    /// Perform a blocking graceful close of this stream.
+    ///
+    virtual
+    void
+    graceful_close() = 0;
+
+    /// Initiate a non-blocking graceful close of this stream.
+    ///
+    virtual
+    void
+    async_graceful_close(graceful_close_handler_t) = 0;
+
+    /// Perform a blocking read on this stream.
+    ///
+    virtual
+    std::size_t
+    read(mutable_buffer_t const&) = 0;
+
+    /// Perform a blocking read on this stream.
+    ///
+    virtual
+    std::size_t
+    read(mutable_buffer_t const&, std::error_code&) = 0;
+
+    /// Initiate a non-blocking read on this stream.
+    ///
+    virtual
+    void
+    async_read(mutable_buffer_t const&, read_handler_t) = 0;
+
+    /// Perform a blocking write on this stream.
+    ///
+    virtual
+    std::size_t
+    write(const_buffer_t const&) = 0;
+
+    /// Perform a blocking write on this stream.
+    ///
+    virtual
+    std::size_t
+    write(const_buffers_t const&) = 0;
+
+    /// Initiate a non-block write on this stream.
+    ///
+    virtual
+    std::size_t
+    write(const_buffer_t const&, std::error_code&) = 0;
+
+    /// Initiate a non-block write on this stream.
+    ///
+    virtual
+    std::size_t
+    write(const_buffers_t const&, std::error_code&) = 0;
+
+    /// Initiate a non-blocking write on this stream.
+    ///
+    virtual
+    void
+    async_write(const_buffer_t const&, write_handler_t) = 0;
+
+    /// Initiate a non-blocking write on this stream.
+    ///
+    virtual
+    void
+    async_write(const_buffers_t const&, write_handler_t) = 0;
+
+  protected:
+    stream_t();
+
+    stream_t(stream_t const&) = delete;
+    stream_t(stream_t&&) = delete;
+
+    stream_t& operator=(stream_t const&) = delete;
+    stream_t& operator=(stream_t&&) = delete;
+
+  };
+
+} // namespace code::seafire::common::io
+
+#endif

code/seafire/common/io/tcp-acceptor.cxx

@@ -0,0 +1,36 @@
+#include <code/seafire/common/io/tcp-acceptor.hxx>
+#include <code/seafire/common/io/tcp-socket.hxx>
+
+
+namespace code::seafire::common::io
+{
+
+  tcp_acceptor_t::
+  tcp_acceptor_t(asio::io_context& io_context,
+                 asio::ip::tcp::endpoint const& endpoint)
+    : acceptor_{io_context, endpoint}
+  {}
+
+  tcp_acceptor_t::
+  ~tcp_acceptor_t() noexcept = default;
+
+  asio::any_io_executor const&
+  tcp_acceptor_t::
+  get_executor()
+  {
+    return acceptor_.get_executor();
+  }
+
+  void
+  tcp_acceptor_t::
+  async_accept(accept_handler_t handler)
+  {
+    auto bound = [handler](std::error_code const& ec, asio::ip::tcp::socket socket)
+    {
+      handler(ec, std::make_unique<tcp_socket_t>(std::move(socket)));
+    };
+
+    acceptor_.async_accept(bound);
+  }
+
+} // namespace code::seafire::common::io

code/seafire/common/io/tcp-acceptor.hxx

@@ -0,0 +1,43 @@
+#ifndef code__seafire__common__io__tcp_acceptor_hxx_
+#define code__seafire__common__io__tcp_acceptor_hxx_
+
+#include <code/seafire/common/diagnostics.hxx>
+
+#include <code/seafire/common/io/acceptor.hxx>
+
+#include <asio.hpp>
+
+namespace code::seafire::common::io
+{
+
+  /// Implements an tcp acceptor.
+  ///
+  class tcp_acceptor_t
+    : public acceptor_t
+  {
+  public:
+    tcp_acceptor_t(asio::io_context&,
+                   asio::ip::tcp::endpoint const&);
+
+    tcp_acceptor_t(tcp_acceptor_t const&) = delete;
+    tcp_acceptor_t(tcp_acceptor_t&&) = delete;
+
+    ~tcp_acceptor_t() noexcept override;
+
+    asio::any_io_executor const&
+    get_executor() override;
+
+    void
+    async_accept(accept_handler_t) override;
+
+    tcp_acceptor_t& operator=(tcp_acceptor_t const&) = delete;
+    tcp_acceptor_t& operator=(tcp_acceptor_t&&) = delete;
+
+  private:
+    asio::ip::tcp::acceptor acceptor_;
+
+  };
+
+} // namespace code::seafire::common::io
+
+#endif

code/seafire/common/io/tcp-socket.cxx

@@ -0,0 +1,149 @@
+#include <code/seafire/common/io/tcp-socket.hxx>
+
+namespace code::seafire::common::io
+{
+
+  /// Construct a new TCP/IP socket from an asio socket.
+  ///
+  tcp_socket_t::
+  tcp_socket_t(asio::ip::tcp::socket socket)
+    : socket_{std::move(socket)}
+  {}
+
+  tcp_socket_t::
+  ~tcp_socket_t() noexcept = default;
+
+  asio::any_io_executor const&
+  tcp_socket_t::
+  get_executor()
+  {
+    return socket_.get_executor();
+  }
+
+  void
+  tcp_socket_t::
+  cancel()
+  {
+    socket_.cancel();
+  }
+
+  void
+  tcp_socket_t::
+  close()
+  {
+    socket_.close();
+  }
+
+  void
+  tcp_socket_t::
+  close(std::error_code& ec)
+  {
+    socket_.close(ec);
+  }
+
+  void
+  tcp_socket_t::
+  graceful_close()
+  {
+    try {
+      socket_.shutdown(asio::ip::tcp::socket::shutdown_send);
+      socket_.read_some(buffer(throwaway_));
+    }
+    catch (...) {
+      // Ignore errors during shutdown/close.
+      //
+    }
+  }
+
+  void
+  tcp_socket_t::
+  async_graceful_close(graceful_close_handler_t handler)
+  {
+    std::error_code ec;
+    socket_.shutdown(asio::ip::tcp::socket::shutdown_send, ec);
+
+    if (ec) {
+      auto bound = [handler]()
+      {
+        handler();
+      };
+
+      asio::post(get_executor(), bound);
+      return;
+    }
+
+    auto bound = [handler](std::error_code const&, std::size_t)
+    {
+      // Errors are ignored during graceful shutdown/close, so we
+      // don't pass anything to the handler.
+      //
+      handler();
+    };
+
+    socket_.async_read_some(buffer(throwaway_), bound);
+  }
+
+  std::size_t
+  tcp_socket_t::
+  read(mutable_buffer_t const& buffer)
+  {
+    return socket_.read_some(buffer);
+  }
+
+  std::size_t
+  tcp_socket_t::
+  read(mutable_buffer_t const& buffer, std::error_code& ec)
+  {
+    return socket_.read_some(buffer, ec);
+  }
+
+  void
+  tcp_socket_t::
+  async_read(mutable_buffer_t const& buffer, read_handler_t handler)
+  {
+    return socket_.async_read_some(buffer, handler);
+  }
+
+  std::size_t
+  tcp_socket_t::
+  write(const_buffer_t const& buffer)
+  {
+    return asio::write(socket_, buffer);
+  }
+
+  std::size_t
+  tcp_socket_t::
+  write(const_buffers_t const& buffers)
+  {
+    return asio::write(socket_, buffers);
+  }
+
+  std::size_t
+  tcp_socket_t::
+  write(const_buffer_t const& buffer, std::error_code& ec)
+  {
+    return asio::write(socket_, buffer, ec);
+  }
+
+  std::size_t
+  tcp_socket_t::
+  write(const_buffers_t const& buffers, std::error_code& ec)
+  {
+    return asio::write(socket_, buffers, ec);
+  }
+
+  void
+  tcp_socket_t::
+  async_write(const_buffer_t const& buffer, write_handler_t handler)
+  {
+    asio::async_write(socket_, buffer, handler);
+  }
+
+  void
+  tcp_socket_t::
+  async_write(const_buffers_t const& buffers, write_handler_t handler)
+  {
+    asio::async_write(socket_, buffers, handler);
+  }
+
+} // namespace code::seafire::common::io

code/seafire/common/io/tcp-socket.hxx

@@ -0,0 +1,82 @@
+#ifndef code__seafire__common__io__tcp_socket_hxx_
+#define code__seafire__common__io__tcp_socket_hxx_
+
+#include <code/seafire/common/io/buffer.hxx>
+#include <code/seafire/common/io/stream.hxx>
+
+#include <asio.hpp>
+
+namespace code::seafire::common::io
+{
+
+  /// Implements a TCP/IP socket.
+  ///
+  class tcp_socket_t
+    : public stream_t
+  {
+  public:
+    explicit
+    tcp_socket_t(asio::ip::tcp::socket);
+
+    tcp_socket_t(tcp_socket_t const&) = delete;
+    tcp_socket_t(tcp_socket_t&&) = delete;
+
+    ~tcp_socket_t() noexcept override;
+
+    asio::any_io_executor const&
+    get_executor() override;
+
+    void
+    cancel() override;
+
+    void
+    close() override;
+
+    void
+    close(std::error_code&) override;
+
+    void
+    graceful_close() override;
+
+    void
+    async_graceful_close(graceful_close_handler_t) override;
+
+    std::size_t
+    read(mutable_buffer_t const&) override;
+
+    std::size_t
+    read(mutable_buffer_t const&, std::error_code&) override;
+
+    void
+    async_read(mutable_buffer_t const&, read_handler_t) override;
+
+    std::size_t
+    write(const_buffer_t const&) override;
+
+    std::size_t
+    write(const_buffers_t const&) override;
+
+    std::size_t
+    write(const_buffer_t const&, std::error_code&) override;
+
+    std::size_t
+    write(const_buffers_t const&, std::error_code&) override;
+
+    void
+    async_write(const_buffer_t const&, write_handler_t) override;
+
+    void
+    async_write(const_buffers_t const&, write_handler_t) override;
+
+    tcp_socket_t& operator=(tcp_socket_t const&) = delete;
+    tcp_socket_t& operator=(tcp_socket_t&&) = delete;
+
+  private:
+    asio::ip::tcp::socket socket_;
+    char throwaway_[1];
+
+  };
+
+} // namespace code::seafire::common::io
+
+#endif

code/seafire/common/traits.hxx

@@ -0,0 +1,162 @@
+#ifndef code__seafire__common__traits_hxx_
+#define code__seafire__common__traits_hxx_
+
+#include <optional>
+#include <tuple>
+#include <type_traits>
+
+namespace code::seafire::common::traits
+{
+
+  // is_optional
+  //
+
+  template<typename T>
+  struct is_optional
+    : std::false_type
+  {};
+
+  template<typename T>
+  struct is_optional<std::optional<T>>
+    : std::true_type
+  {};
+
+  template<typename T>
+  constexpr bool is_optional_v{is_optional<T>::value};
+
+  // remove_optional
+  //
+
+  template<typename T>
+  struct remove_optional
+  {
+    using type = T;
+  };
+
+  template<typename T>
+  struct remove_optional<std::optional<T>>
+  {
+    using type = T;
+  };
+
+  template<typename T>
+  using remove_optional_t = remove_optional<T>::type;
+
+  // add_optional
+  //
+
+  template<typename T>
+  std::optional<remove_optional_t<T>>
+  add_optional(remove_optional<T>&& non_optional)
+  {
+    return std::optional<remove_optional<T>>{non_optional};
+  }
+
+  // function_traits
+  //
+
+  template<typename>
+  struct function_traits;
+
+  template<typename Ret, typename... Args>
+  struct function_traits<Ret(Args...)>
+  {
+    static constexpr std::size_t arity = sizeof...(Args);
+    using return_type = std::decay_t<Ret>;
+    using argument_tuple = std::tuple<std::decay_t<Args>...>;
+  };
+
+  template<typename Ret, typename Class, typename... Args>
+  struct function_traits<Ret (Class::*)(Args...)>
+  {
+    static constexpr std::size_t arity = sizeof...(Args);
+    using return_type = std::decay_t<Ret>;
+    using class_type = Class;
+    using argument_tuple = std::tuple<std::decay_t<Args>...>;
+  };
+
+  template<typename Ret, typename Class, typename... Args>
+  struct function_traits<Ret (Class::*)(Args...) const>
+  {
+    static constexpr std::size_t arity = sizeof...(Args);
+    using return_type = std::decay_t<Ret>;
+    using class_type = Class;
+    using argument_tuple = std::tuple<std::decay_t<Args>...>;
+  };
+
+  template<typename Ret, typename... Args>
+  struct function_traits<Ret(*)(Args...)>
+  {
+    static constexpr std::size_t arity = sizeof...(Args);
+    using return_type = std::decay_t<Ret>;
+    using argument_tuple = std::tuple<std::decay_t<Args>...>;
+  };
+
+  // return_type_t
+  //
+
+  template<typename F>
+  using return_type_t = typename function_traits<F>::return_type;
+
+  // first_arg
+  //
+
+  template<typename F>
+  struct first_arg
+  {
+    using function_traits = traits::function_traits<F>;
+    using type = std::tuple_element_t<0, typename function_traits::argument_tuple>;
+  };
+
+  template<typename F>
+  using first_arg_t = first_arg<F>::type;
+
+  // function_arg_n
+  //
+
+  template<
+    typename F,
+    std::size_t arg,
+    std::size_t arity = function_traits<F>::arity
+  >
+  struct function_arg_n;
+
+  template<
+    typename F,
+    std::size_t arg
+  >
+  struct function_arg_n<F, arg, 0>
+  {
+    using function_traits = traits::function_traits<F>;
+    using type = void;
+  };
+
+  template<
+    typename F,
+    std::size_t arg
+  >
+  struct function_arg_n<F, arg, 1>
+  {
+    using function_traits = traits::function_traits<F>;
+    using type = std::tuple_element_t<arg, typename function_traits::argument_tuple>;
+  };
+
+  template<
+    typename F,
+    std::size_t arg
+  >
+  struct function_arg_n<F, arg, 2>
+  {
+    using function_traits = traits::function_traits<F>;
+    using type = std::tuple_element_t<arg, typename function_traits::argument_tuple>;
+  };
+
+  template<
+    typename F,
+    std::size_t arg
+  >
+  using function_arg_n_t = function_arg_n<F, arg>::type;
+
+} // namespace code::seafire::common::traits
+
+#endif

code/seafire/common/version.hxx.in

@@ -0,0 +1,37 @@
+#ifndef code__seafire__common__version_hxx_
+#define code__seafire__common__version_hxx_
+
+// The numeric version format is AAAAABBBBBCCCCCDDDE where:
+//
+// AAAAA - major version number
+// BBBBB - minor version number
+// CCCCC - bugfix version number
+// DDD   - alpha / beta (DDD + 500) version number
+// E     - final (0) / snapshot (1)
+//
+// When DDDE is not 0, 1 is subtracted from AAAAABBBBBCCCCC. For example:
+//
+// Version      AAAAABBBBBCCCCCDDDE
+//
+// 0.1.0        0000000001000000000
+// 0.1.2        0000000001000020000
+// 1.2.3        0000100002000030000
+// 2.2.0-a.1    0000200001999990010
+// 3.0.0-b.2    0000299999999995020
+// 2.2.0-a.1.z  0000200001999990011
+//
+#define LIBCODE_SEAFIRE_COMMON_VERSION       $libcode_seafire_common.version.project_number$ULL
+#define LIBCODE_SEAFIRE_COMMON_VERSION_STR   "$libcode_seafire_common.version.project$"
+#define LIBCODE_SEAFIRE_COMMON_VERSION_ID    "$libcode_seafire_common.version.project_id$"
+#define LIBCODE_SEAFIRE_COMMON_VERSION_FULL  "$libcode_seafire_common.version$"
+
+#define LIBCODE_SEAFIRE_COMMON_VERSION_MAJOR $libcode_seafire_common.version.major$
+#define LIBCODE_SEAFIRE_COMMON_VERSION_MINOR $libcode_seafire_common.version.minor$
+#define LIBCODE_SEAFIRE_COMMON_VERSION_PATCH $libcode_seafire_common.version.patch$
+
+#define LIBCODE_SEAFIRE_COMMON_PRE_RELEASE   $libcode_seafire_common.version.pre_release$
+
+#define LIBCODE_SEAFIRE_COMMON_SNAPSHOT_SN   $libcode_seafire_common.version.snapshot_sn$ULL
+#define LIBCODE_SEAFIRE_COMMON_SNAPSHOT_ID   "$libcode_seafire_common.version.snapshot_id$"
+
+#endif

manifest

@@ -0,0 +1,12 @@
+: 1
+name: libcode-seafire-common
+version: 0.1.0-a.0.z
+language: c++
+summary: libcode-seafire-common C++ library
+license: BSD-4-Clause
+description-file: README.md
+url: https://helloryan.se/code/
+email: ryan@helloryan.se
+depends: * build2 >= 0.17.0
+depends: * bpkg >= 0.17.0
+depends: libasio ^1.29.0

repositories.manifest

@@ -0,0 +1,7 @@
+: 1
+summary: libcode-seafire-common project repository
+
+:
+role: prerequisite
+location: https://pkg.cppget.org/1/beta
+trust: 70:64:FE:E4:E0:F3:60:F1:B4:51:E1:FA:12:5C:E0:B3:DB:DF:96:33:39:B9:2E:E5:C2:68:63:4C:A6:47:39:43

tests/.gitignore

@@ -0,0 +1,8 @@
+# Test executables.
+#
+driver
+
+# Testscript output directories (can be symlinks).
+#
+test
+test-*

tests/build/.gitignore

@@ -0,0 +1,4 @@
+/config.build
+/root/
+/bootstrap/
+build/

tests/build/bootstrap.build

@@ -0,0 +1,5 @@
+project = # Unnamed tests subproject.
+
+using config
+using test
+using dist

tests/build/root.build

@@ -0,0 +1,16 @@
+cxx.std = latest
+
+using cxx
+
+hxx{*}: extension = hxx
+ixx{*}: extension = ixx
+txx{*}: extension = txx
+cxx{*}: extension = cxx
+
+# Every exe{} in this subproject is by default a test.
+#
+exe{*}: test = true
+
+# The test target for cross-testing (running tests under Wine, etc).
+#
+test.target = $cxx.target

tests/buildfile

@@ -0,0 +1 @@
+./: {*/ -build/}