more task functionality

lib/src/task.rs

@@ -0,0 +1,96 @@
+use crate::{status::TCStatus, string::TCString, uuid::TCUuid};
+use taskchampion::Task;
+
+/// A task, as publicly exposed by this library.
+///
+/// A task carries no reference to the replica that created it, and can
+/// be used until it is freed or converted to a TaskMut.
+pub struct TCTask {
+    inner: Task,
+}
+
+impl TCTask {
+    pub(crate) fn as_ptr(task: Task) -> *mut TCTask {
+        Box::into_raw(Box::new(TCTask { inner: task }))
+    }
+}
+
+/// Utility function to allow using `?` notation to return an error value.
+fn wrap<'a, T, F>(task: *const TCTask, f: F, err_value: T) -> T
+where
+    F: FnOnce(&Task) -> anyhow::Result<T>,
+{
+    let task: &'a Task = task_ref(task);
+    match f(task) {
+        Ok(v) => v,
+        Err(e) => {
+            /*
+            let error = e.to_string();
+            let error = match CString::new(error.as_bytes()) {
+                Ok(e) => e,
+                Err(_) => CString::new("(invalid error message)".as_bytes()).unwrap(),
+            };
+            */
+            //task.error = Some(error);
+            err_value
+        }
+    }
+}
+
+/// Utility function to safely convert *const TCTask into &Task
+fn task_ref(task: *const TCTask) -> &'static Task {
+    debug_assert!(!task.is_null());
+    unsafe { &(*task).inner }
+}
+
+/// Get a task's UUID.
+#[no_mangle]
+pub extern "C" fn tc_task_get_uuid<'a>(task: *const TCTask) -> TCUuid {
+    let task: &'a Task = task_ref(task);
+    let uuid = task.get_uuid();
+    uuid.into()
+}
+
+/// Get a task's status.
+#[no_mangle]
+pub extern "C" fn tc_task_get_status<'a>(task: *const TCTask) -> TCStatus {
+    let task: &'a Task = task_ref(task);
+    task.get_status().into()
+}
+
+/* TODO
+ * into_mut
+ * get_taskmap
+ */
+
+/// Get a task's description, or NULL if the task cannot be represented as a C string (e.g., if it
+/// contains embedded NUL characters).
+#[no_mangle]
+pub extern "C" fn tc_task_get_description<'a>(task: *const TCTask) -> *mut TCString {
+    wrap(
+        task,
+        |task| Ok(TCString::return_string(task.get_description())?),
+        std::ptr::null_mut(),
+    )
+}
+
+/* TODO
+ * get_wait
+ * is_waiting
+ * is_active
+ * has_tag
+ * get_tags
+ * get_annotations
+ * get_uda
+ * get_udas
+ * get_legacy_uda
+ * get_legacy_udas
+ * get_modified
+ */
+
+/// Free a task.
+#[no_mangle]
+pub extern "C" fn tc_task_free<'a>(task: *mut TCTask) {
+    debug_assert!(!task.is_null());
+    drop(unsafe { Box::from_raw(task) });
+}