[Rust] Add builder API for creating workflows

`Workflow::new` is replaced by `Workflow::build` that returns a
`Builder` type that supports the operations that mutate a workflow, such
as registering activities.

`Workflow::instance` is replaced by `Workflow::get` to make clear that
it is intended to look up an existing workflow.

`Workflow::cloned` is introduced to wrap the common pattern of
retrieving an existing workflow and cloning it with the same name in
order to modify it.

`Builder::activity_before` / `Builder::activity_after` are introduced to
wrap the common pattern of registering an activity then inserting it
before or after a given activity.

1 files changed, 14 insertions, 11 deletions

diff --git a/plugins/svd/src/lib.rs b/plugins/svd/src/lib.rs
index b02b1ec2..3a40d2c0 100644
--- a/plugins/svd/src/lib.rs
+++ b/plugins/svd/src/lib.rs
@@ -9,7 +9,6 @@ use binaryninja::logger::Logger;
 use binaryninja::workflow::{Activity, AnalysisContext, Workflow};
 use log::LevelFilter;
 
-pub const LOADER_ACTIVITY_NAME: &str = "analysis.svd.loader";
 const LOADER_ACTIVITY_CONFIG: &str = r#"{
     "name": "analysis.svd.loader",
     "title" : "SVD Loader",
@@ -62,7 +61,10 @@ impl Command for LoadSVDFile {
 #[allow(non_snake_case)]
 #[cfg(not(feature = "demo"))]
 pub extern "C" fn CorePluginInit() -> bool {
-    plugin_init();
+    if plugin_init().is_err() {
+        log::error!("Failed to initialize SVD plug-in");
+        return false;
+    }
     true
 }
 
@@ -70,11 +72,14 @@ pub extern "C" fn CorePluginInit() -> bool {
 #[allow(non_snake_case)]
 #[cfg(feature = "demo")]
 pub extern "C" fn SVDPluginInit() -> bool {
-    plugin_init();
+    if plugin_init().is_err() {
+        log::error!("Failed to initialize SVD plug-in");
+        return false;
+    }
     true
 }
 
-fn plugin_init() {
+fn plugin_init() -> Result<(), ()> {
     Logger::new("SVD").with_level(LevelFilter::Debug).init();
 
     binaryninja::command::register_command(
@@ -113,12 +118,10 @@ fn plugin_init() {
     };
 
     // Register new workflow activity to load svd information.
-    let old_module_meta_workflow = Workflow::instance("core.module.metaAnalysis");
-    let module_meta_workflow = old_module_meta_workflow.clone_to("core.module.metaAnalysis");
     let loader_activity = Activity::new_with_action(LOADER_ACTIVITY_CONFIG, loader_activity);
-    module_meta_workflow
-        .register_activity(&loader_activity)
-        .unwrap();
-    module_meta_workflow.insert("core.module.loadDebugInfo", [LOADER_ACTIVITY_NAME]);
-    module_meta_workflow.register().unwrap();
+    Workflow::cloned("core.module.metaAnalysis")
+        .ok_or(())?
+        .activity_before(&loader_activity, "core.module.loadDebugInfo")?
+        .register()?;
+    Ok(())
 }