Fix 5: Allow backward-compatibility and add plugin-template-v2

crates/ocs_plugin_api/src/lib.rs

@@ -41,7 +41,9 @@ pub mod shm;
 #[cfg(feature = "host")]
 pub mod runner;
 
-pub use manifest::{ApiVersion, PluginManifest, API_VERSION, API_VERSION_MIN_SUPPORTED};
+pub use manifest::{
+    host_accepts_plugin_version, ApiVersion, PluginManifest, API_VERSION, API_VERSION_MIN_SUPPORTED,
+};
 pub use ribbon::{CadModule, IconKind, ModuleEvent, RibbonGroup, RibbonItem, StyleKey, ToolDef};
 
 #[cfg(feature = "host")]

crates/ocs_plugin_api/src/manifest.rs

@@ -28,6 +28,13 @@ impl ApiVersion {
     }
 }
 
+/// True when a plugin built against `plugin_major` can be loaded by this host.
+/// The host supports majors from `API_VERSION_MIN_SUPPORTED` up to
+/// `API_VERSION`.
+pub fn host_accepts_plugin_version(plugin_major: u32) -> bool {
+    plugin_major >= API_VERSION_MIN_SUPPORTED && plugin_major <= API_VERSION
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

crates/ocs_plugin_api/src/runner.rs

@@ -152,7 +152,7 @@ unsafe fn load_plugin(path: &Path) -> Result<Box<dyn BuiltinPlugin>, Box<dyn std
         .get(b"ocs_plugin_api_version")
         .map_err(|_| "missing ocs_plugin_api_version symbol")?;
     let v = version();
-    if v < crate::API_VERSION_MIN_SUPPORTED || v > crate::API_VERSION {
+    if !crate::host_accepts_plugin_version(v) {
         return Err(format!(
             "API version {v} is incompatible (host supports {}-{})",
             crate::API_VERSION_MIN_SUPPORTED,

crates/plugin-template-api2/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "plugin-template-api2"
+version = "0.1.0"
+edition = "2021"
+description = "API v2 compatibility fixture for the out-of-process plugin path."
+license = "GPL-3.0-only"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+ocs_plugin_api = { path = "../ocs_plugin_api", features = ["host"] }
+acadrust = "0.3.4"

crates/plugin-template-api2/src/lib.rs

@@ -0,0 +1,76 @@
+//! API v2 compatibility fixture.
+//!
+//! Mimics an old plugin compiled against `ocs_plugin_api` v2: it reports API
+//! major 2 from `ocs_plugin_api_version()` and implements only the v2 surface
+//! (`HostApi` methods up to `start_interactive`). The current host must still
+//! be able to load and dispatch it.
+
+use ocs_plugin_api::host::{BuiltinPlugin, HostApi};
+use ocs_plugin_api::manifest::{ApiVersion, PluginManifest};
+use ocs_plugin_api::ribbon::{CadModule, IconKind, ModuleEvent, RibbonGroup, RibbonItem, ToolDef};
+
+static MANIFEST: PluginManifest = PluginManifest {
+    id: "opencad.my_plugin",
+    name: "My Plugin",
+    version: env!("CARGO_PKG_VERSION"),
+    description: "API v2 fixture plugin.",
+    api_version: ApiVersion { major: 2 },
+    ribbon_order: 60,
+    xdata_apps: &[],
+    command_prefixes: &["MP_"],
+};
+
+struct MyModule;
+
+impl CadModule for MyModule {
+    fn id(&self) -> &'static str {
+        "my_plugin"
+    }
+    fn title(&self) -> &'static str {
+        "My Plugin"
+    }
+    fn ribbon_groups(&self) -> Vec<RibbonGroup> {
+        vec![RibbonGroup {
+            title: "Tools",
+            tools: vec![RibbonItem::LargeTool(ToolDef {
+                id: "MP_HELLO",
+                label: "Hello",
+                icon: IconKind::Glyph("*"),
+                event: ModuleEvent::Command("MP_HELLO".to_string()),
+            })],
+        }]
+    }
+}
+
+struct MyPlugin;
+
+impl BuiltinPlugin for MyPlugin {
+    fn manifest(&self) -> &'static PluginManifest {
+        &MANIFEST
+    }
+    fn ribbon(&self) -> Box<dyn CadModule> {
+        Box::new(MyModule)
+    }
+    fn dispatch(&self, host: &mut dyn HostApi, cmd: &str) -> bool {
+        match cmd {
+            "MP_HELLO" => {
+                host.push_info("Hello from API v2 plugin");
+                true
+            }
+            _ => false,
+        }
+    }
+}
+
+// Custom C-ABI export that reports API v2, emulating an older build of
+// `ocs_plugin_api::export_plugin!`.
+#[no_mangle]
+pub extern "C" fn ocs_plugin_api_version() -> u32 {
+    2
+}
+
+#[no_mangle]
+pub extern "C" fn ocs_plugin_register() -> *mut Box<dyn BuiltinPlugin> {
+    let plugin: Box<dyn BuiltinPlugin> = Box::new(MyPlugin);
+    Box::into_raw(Box::new(plugin))
+}