Have Meson orchestrate the whole build rather than stack.

As a part of this, I changed the file layout to:

rt/ - the Montis runtime
plug/ - the Montis plugin
wlroots/ - wlroots

1 files changed, 190 insertions, 0 deletions

diff --git a/rt/include/plugin.h b/rt/include/plugin.h
new file mode 100644
index 0000000..4d69d76
--- /dev/null
+++ b/rt/include/plugin.h
@@ -0,0 +1,190 @@
+#ifndef _PLUGIN_H_
+#define _PLUGIN_H_
+
+#include <dlfcn.h>
+#include <linux/limits.h>
+#include <pthread.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <wlr/types/wlr_input_device.h>
+#include <wlr/types/wlr_keyboard.h>
+#include <wlr/types/wlr_pointer.h>
+
+#include "plugin_types.h"
+#include <foreign_intf.h>
+
+/*
+ * Marker macro to define what functions should be exported. This generates the
+ * interface which the plugin needs to implement.
+ */
+#define EXPORT(a) a
+
+#define EXPORT_INCLUDE(a)
+
+// clang-format off
+EXPORT_INCLUDE(<foreign_intf.h>)
+EXPORT_INCLUDE(<wlr/types/wlr_keyboard.h>)
+EXPORT_INCLUDE(<wlr/types/wlr_input_device.h>)
+EXPORT_INCLUDE(<wlr/types/wlr_pointer.h>)
+// clang-format on
+
+#define MAX_QUEUED_ACTIONS 8
+
+typedef void *dlhandle_t;
+
+/* Opaque state for a plugin. Not to be touched by the harness (not that it
+ * really can be.) */
+
+struct PLUGIN;
+/* This structure represents an action requested by the plugin for the harness.
+ */
+typedef struct {
+  int (*action)(struct PLUGIN *requester, void *arg);
+  void (*arg_dtor)(void *arg);
+  union {
+    void *ptr_arg;
+    int int_arg;
+    char *str_arg;
+  };
+} requested_action_t;
+
+/*
+ * Structure for the plugin.
+ */
+typedef struct PLUGIN {
+  /* The argc this plugin is loaded with. Typically the argc from main(). */
+  int argc;
+
+  /* The argv this plugin is loaded with. Typically the argv from main(). */
+  char **argv;
+
+  /* Filename the plugin is loaded from. */
+  char filename[PATH_MAX];
+
+  /* Interface to the harness that this plugin can use. */
+  foreign_interface_t foreign_intf;
+
+  /* Opaque state of this plugin. The state is usually some kind of pointer to
+   * the plugin state, but all the harness knows is the opaque state is a
+   * pointer-sized piece of data.
+   *
+   * This opaque state is used in a linear pattern where the handlers take the
+   * opaque state, maybe operate on it, and return a new opaque state, which is
+   * then passed to the next handler, etc. It is on the plugin to properly
+   * manager the memory for this state and to destroy it upon teardown.
+   *
+   * It's guaranteed that this state is used linearly, meaning the harness gives
+   * up all ownership to it once passed into a handler. */
+  opqst_t state;
+
+  /* This plugin's lock. This avoids potential issues with multiple threads
+   * trying to change the opaque state at once which can lead to undesireable
+   * outcomes. */
+  pthread_mutex_t lock;
+
+  /** Set to not-zero if this plugin is initialized, otherwise set to zero. */
+  int initialized;
+
+  /* The handle to the shared library. */
+  dlhandle_t library_handle;
+
+  /* Pointer to the plugin name. This is in the shared library and a
+   * null-terminated string. If the library does not have a plugin name, this
+   * will be NULL. */
+  const char *plugin_name;
+
+  /**
+   * Initializes the plugin on the first time, and only the first time, it is
+   * loaded. This is used to do things like setup a runtime that cannot be
+   * reliably torn down. It is up to the plugin to ensure this won't interfere
+   * with hot-reloading.
+   */
+  EXPORT(void (*plugin_metaload)(int argc, char **argv));
+
+  /** Intializes the plugin with the given argc/argv. This is the first thing
+   * called on the plugin and is called immediately after the library is loaded.
+   */
+  EXPORT(void (*plugin_load)(int argc, char **argv, foreign_interface_t *intf));
+
+  /* Start the plugin with the marshalled state from the previous plugin.
+   *
+   * This should return the opaque state from the mashalled_state.
+   *
+   * This function should not fail if the state cannot be demarshalled, rather a
+   * default state should be returned. This is because changing the plugin and
+   * hot-reloading can produce incompatibilities between the old state and the
+   * new state, and this should not cause a failure.
+   */
+  EXPORT(opqst_t (*plugin_hot_start)(uint8_t *mashalled_state, uint32_t n));
+
+  /*
+   * Starts the plugin without a marshalled state. Happens during the first boot
+   * when there is not state.
+   */
+  EXPORT(opqst_t (*plugin_cold_start)());
+
+  /*
+   * Marshals the state to a bytestring. The returned pointer should be malloc'd
+   * on the heap. The harness takes ownership of the malloc'd pointer.
+   *
+   * This is usually called in preparation for a teardown followed by a
+   * hot-start.
+   */
+  EXPORT(uint8_t *(*plugin_marshal_state)(opqst_t st, uint32_t *szout));
+
+  /*
+   * Teardown the plugin in preperation for the library's imminent unloading.
+   */
+  EXPORT(void (*plugin_teardown)(opqst_t));
+
+  /*
+   * Handles a keybinding.
+   */
+  EXPORT(opqst_t (*plugin_handle_keybinding)(
+      struct wlr_keyboard *keyboard, struct wlr_keyboard_key_event *event,
+      uint32_t modifiers, uint32_t keysym, uint32_t codepoint, int *out_handled,
+      opqst_t state));
+
+  EXPORT(opqst_t (*plugin_handle_button)(struct wlr_pointer_button_event *event,
+                                         uint32_t modifiers, opqst_t state));
+
+  /*
+   * Handles a surface being mapped, unmapped or destroyed.
+   */
+  EXPORT(opqst_t (*plugin_handle_surface)(void *surface, surface_event_t event,
+                                          opqst_t));
+
+  /* List of requested actions by the plugin. Right now there is a maximum of 8
+   * allowed at one time. That should be plenty. The actions should be flushed
+   * after each call to a handler anyway. */
+  size_t n_requested_actions;
+  requested_action_t requested_actions[MAX_QUEUED_ACTIONS];
+} plugin_t;
+
+#undef EXPORT
+#undef EXPORT_INCLUDE
+
+/* Reloads the plugin. This tears down the existing plugin, marshals the state
+ * for it and reloads it.
+ *
+ * This function will call dlclose on the plugin's library handle.
+ */
+int plugin_hot_reload(int argc, char **argv, const char *filepath,
+                      plugin_t *plugin);
+
+/*
+ * Like hot-reload, but uses the same parameters the plugin was originally
+ * loaded with.
+ */
+int plugin_hot_reload_same_state(plugin_t *plugin);
+
+/* Starts a plugin in a cold state. Called after load_plugin_from_file. */
+void plugin_cold_start(plugin_t *plugin);
+
+/* Reads a plugin from a filename. */
+int load_plugin_from_file(int argc, char **argv, const char *filename,
+                          plugin_t *plugin);
+
+void plugin_run_requested_actions(plugin_t *plugin);
+
+#endif /* _PLUGIN_H_ */