Initial commit for Project Wetterhorn.

Project Wetterhorn is an attempt to make a Wayland compositor inspired
by XMonad. This project is different from other Wayland compositors in
that one of its core tenets is dynamic reloading of as much code as
possible.

The architecture is going to be:
  - A harness, written in C, supplies the basic components to create a
    Wayland compositor. This will be modeled on tinywl, sway, dwl and
    others and use wlroots as its main abstraction to wayland.

  - A dynamic library, written in Haskell, will provide bindings for
    handling events and managing the windows. This dynamic library can
    be recompiled and reloaded at runtime, allowing the user to write
    their 'configuration' in Haskell, much as XMonad, but without
    needing to reboot the whole compositor.

The boundaries of responsibilities between the harness and the plugin
will be an evolving matter, depending on how important the dynamic
reloading is for that specific responsibility and the need for raw
performance.

I chose this architecture as a compromise. With this architecture,
dynamic loading is achieved without the need to define a whole protocol
around controlling the window management, but this also gives the plugin
the full ability to control the compositor because it is literally a
part of it making anything possible in theory, which is a huge benefit.

12 files changed, 264 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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index 0000000..76467e6
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+.stack-work/
+*~
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..dbeac0b
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright Josh Rahm name here (c) 2024
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * 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.
+
+    * Neither the name of Author name here nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"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 THE COPYRIGHT
+OWNER OR CONTRIBUTORS 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.
diff --git a/README.md b/README.md
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index 0000000..92122d8
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+# wetterhorn
diff --git a/package.yaml b/package.yaml
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index 0000000..37bf008
--- /dev/null
+++ b/package.yaml
@@ -0,0 +1,65 @@
+name:                wetterhorn
+version:             0.1.0.0
+github:              "githubuser/wetterhorn"
+license:             BSD-3-Clause
+author:              "Author name here"
+maintainer:          "example@example.com"
+copyright:           "2024 Author name here"
+
+extra-source-files:
+- README.md
+- CHANGELOG.md
+
+# Metadata used when publishing your package
+# synopsis:            Short description of your package
+# category:            Web
+
+# To avoid duplicated efforts in documentation and dealing with the
+# complications of embedding Haddock markup inside cabal files, it is
+# common to point users to the README.md file.
+description:         Please see the README on GitHub at <https://github.com/githubuser/wetterhorn#readme>
+
+dependencies:
+- base >= 4.7 && < 5
+- mtl
+
+ghc-options:
+- -Wall
+- -Wcompat
+- -Widentities
+- -Wincomplete-record-updates
+- -Wincomplete-uni-patterns
+- -Wmissing-export-lists
+- -Wmissing-home-modules
+- -Wpartial-fields
+- -Wredundant-constraints
+- -fPIC
+
+executables:
+  wtr.so:
+    main:                Main.hs
+    source-dirs:         src
+    c-sources: src/harness_adapter.c
+    ghc-options:
+    - -shared
+    - -fPIC
+    - -dynamic
+    - -lHSrts-1.0.2-ghc9.4.7
+
+  wtr_harness:
+    main: src/harness/main.c
+    ghc-options:
+      - -no-hs-main
+    cc-options:
+      - -ldl
+
+tests:
+  wetterhorn-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - wetterhorn
diff --git a/src/Lib.hs b/src/Lib.hs
new file mode 100644
index 0000000..d36ff27
--- /dev/null
+++ b/src/Lib.hs
@@ -0,0 +1,6 @@
+module Lib
+    ( someFunc
+    ) where
+
+someFunc :: IO ()
+someFunc = putStrLn "someFunc"
diff --git a/src/Main.hs b/src/Main.hs
new file mode 100644
index 0000000..c43ef13
--- /dev/null
+++ b/src/Main.hs
@@ -0,0 +1,14 @@
+module Main (main) where
+import Control.Monad.Writer (execWriter, MonadWriter (tell))
+
+foreign export ccall call_in :: IO ()
+call_in :: IO ()
+call_in = putStrLn $ execWriter $ do
+  tell "Yo,"
+  tell " This was "
+  tell "Called"
+  tell " From"
+  tell " C!!"
+
+main :: IO ()
+main = putStrLn "This should be dynamically linked!\n"
diff --git a/src/harness/main.c b/src/harness/main.c
new file mode 100644
index 0000000..6666e5e
--- /dev/null
+++ b/src/harness/main.c
@@ -0,0 +1,65 @@
+#include <stdio.h>
+
+#include <dlfcn.h>
+
+typedef void* dllib_t;
+
+dllib_t open_library(const char* library, int* err)
+{
+  dllib_t lib = dlopen(library, RTLD_LAZY);
+
+  if (!lib) {
+    fprintf(stderr, "Error opening shared library: %s\n", dlerror());
+    *err = 1;
+  }
+  *err = 0;
+  return lib;
+}
+
+void* getsym(dllib_t handle, char* sym, int* err)
+{
+  void* ret = dlsym(handle, sym);
+  if (!ret) {
+    fprintf(stderr, "Unable to read symbol '%s'\n", sym);
+    *err |= 1;
+    return NULL;
+  }
+  return ret;
+}
+
+void use_library(int argc, char** argv, dllib_t lib, int* err)
+{
+  *err = 0;
+
+  void (*init)(int* argc, char*** argv) = getsym(lib, "plugin_init", err);
+  void (*teardown)() = getsym(lib, "plugin_teardown", err);
+  void (*sym)() = getsym(lib, "call_in", err);
+
+  if (!sym) {
+    *err = 1;
+    fprintf(stderr, "Unable to find symbol call_in.\n");
+    return;
+  }
+
+  init(&argc, &argv);
+  sym();
+  teardown();
+}
+
+int main(int argc, char** argv)
+{
+  if (!argv[0] && !argv[1]) {
+    fprintf(stderr, "Missing argument.\n");
+    return 1;
+  }
+
+  int err = 0;
+  dllib_t lib = open_library(argv[1], &err);
+
+  if (err) {
+    return err;
+  }
+
+  use_library(argc, argv, lib, &err);
+  return 0;
+}
diff --git a/src/harness_adapter.c b/src/harness_adapter.c
new file mode 100644
index 0000000..9cd8118
--- /dev/null
+++ b/src/harness_adapter.c
@@ -0,0 +1,12 @@
+#include <stdio.h>
+#include "HsFFI.h"
+
+void plugin_init(int* argc, char*** argv)
+{
+  hs_init(argc, argv);
+}
+
+void plugin_teardown()
+{
+  hs_exit();
+}
diff --git a/stack.yaml b/stack.yaml
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index 0000000..65ff04b
--- /dev/null
+++ b/stack.yaml
@@ -0,0 +1,65 @@
+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+resolver: lts-21.21
+# resolver: nightly-2023-09-24
+# resolver: ghc-9.6.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2023-01-01.yaml
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+# extra-deps:
+# - acme-missiles-0.3
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of Stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=2.13"
+#
+# Override the architecture used by Stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by Stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor
diff --git a/test/Spec.hs b/test/Spec.hs
new file mode 100644
index 0000000..cd4753f
--- /dev/null
+++ b/test/Spec.hs
@@ -0,0 +1,2 @@
+main :: IO ()
+main = putStrLn "Test suite not yet implemented"
diff --git a/wtr.so b/wtr.so
new file mode 120000
index 0000000..6f97167
--- /dev/null
+++ b/wtr.so
@@ -0,0 +1 @@
+./.stack-work/dist/x86_64-linux-tinfo6-libc6-pre232/ghc-9.4.7/build/wtr.so/wtr.so
\ No newline at end of file
diff --git a/wtr_harness b/wtr_harness
new file mode 120000
index 0000000..6383cb0
--- /dev/null
+++ b/wtr_harness
@@ -0,0 +1 @@
+./.stack-work/install/x86_64-linux-tinfo6-libc6-pre232/f9d76f7cdc71c3e38ec09dbbb9cee45cabefb3429d6bf1fdf55c7a08b076c991/9.4.7/bin/wtr_harness
\ No newline at end of file