add error handling for tasks

This commit is contained in:
Dustin J. Mitchell 2022-02-01 00:35:02 +00:00
parent 2dc9358085
commit b675cef99c
6 changed files with 93 additions and 52 deletions

View file

@ -150,15 +150,26 @@ static void task_task_add_tag(void) {
tc_task_to_mut(task, rep);
TEST_ASSERT_EQUAL(TC_RESULT_TRUE, tc_task_add_tag(task, tc_string_borrow("next")));
TEST_ASSERT_NULL(tc_task_error(task));
// invalid - synthetic tag
TEST_ASSERT_EQUAL(TC_RESULT_ERROR, tc_task_add_tag(task, tc_string_borrow("PENDING")));
TCString *err = tc_task_error(task);
TEST_ASSERT_NOT_NULL(err);
tc_string_free(err);
// invald - not a valid tag string
TEST_ASSERT_EQUAL(TC_RESULT_ERROR, tc_task_add_tag(task, tc_string_borrow("my tag")));
err = tc_task_error(task);
TEST_ASSERT_NOT_NULL(err);
tc_string_free(err);
// invald - not utf-8
TEST_ASSERT_EQUAL(TC_RESULT_ERROR, tc_task_add_tag(task, tc_string_borrow("\xf0\x28\x8c\x28")));
err = tc_task_error(task);
TEST_ASSERT_NOT_NULL(err);
tc_string_free(err);
// TODO: check error messages
// TODO: test getting the tag
tc_task_free(task);

View file

@ -1,3 +1,6 @@
mod util;
// TODO: #![..]
#[warn(unsafe_op_in_unsafe_fn)]
pub mod replica;
pub mod result;

View file

@ -1,3 +1,4 @@
use crate::util::err_to_tcstring;
use crate::{result::TCResult, status::TCStatus, string::TCString, task::TCTask, uuid::TCUuid};
use taskchampion::{Replica, StorageConfig, Uuid};
@ -75,10 +76,6 @@ impl From<Replica> for TCReplica {
}
}
fn err_to_tcstring(e: impl std::string::ToString) -> TCString<'static> {
TCString::from(e.to_string())
}
/// Utility function to allow using `?` notation to return an error value. This makes
/// a mutable borrow, because most Replica methods require a `&mut`.
fn wrap<'a, T, F>(rep: *mut TCReplica, f: F, err_value: T) -> T

View file

@ -1,3 +1,4 @@
use crate::util::err_to_tcstring;
use crate::{
replica::TCReplica, result::TCResult, status::TCStatus, string::TCString, uuid::TCUuid,
};
@ -15,7 +16,15 @@ use taskchampion::{Tag, Task, TaskMut};
/// be used until it is freed or converted to a TaskMut.
///
/// All `tc_task_..` functions taking a task as an argument require that it not be NULL.
pub enum TCTask {
pub struct TCTask {
/// The wrapped Task or TaskMut
inner: Inner,
/// The error from the most recent operation, if any
error: Option<TCString<'static>>,
}
enum Inner {
/// A regular, immutable task
Immutable(Task),
@ -37,19 +46,7 @@ impl TCTask {
/// The pointer must not be NULL. It is the caller's responsibility to ensure that the
/// lifetime assigned to the reference and the lifetime of the TCTask itself do not outlive
/// the lifetime promised by C.
pub(crate) unsafe fn from_arg_ref<'a>(tctask: *const TCTask) -> &'a Self {
debug_assert!(!tctask.is_null());
&*tctask
}
/// Borrow a TCTask from C as an argument, allowing mutation.
///
/// # Safety
///
/// The pointer must not be NULL. It is the caller's responsibility to ensure that the
/// lifetime assigned to the reference and the lifetime of the TCTask itself do not outlive
/// the lifetime promised by C.
pub(crate) unsafe fn from_arg_ref_mut<'a>(tctask: *mut TCTask) -> &'a mut Self {
pub(crate) unsafe fn from_arg_ref<'a>(tctask: *mut TCTask) -> &'a mut Self {
debug_assert!(!tctask.is_null());
&mut *tctask
}
@ -77,60 +74,64 @@ impl TCTask {
/// The tcreplica pointer must not be NULL, and the replica it points to must not
/// be freed before TCTask.to_immut completes.
unsafe fn to_mut(&mut self, tcreplica: *mut TCReplica) {
*self = match std::mem::replace(self, TCTask::Invalid) {
TCTask::Immutable(task) => {
self.inner = match std::mem::replace(&mut self.inner, Inner::Invalid) {
Inner::Immutable(task) => {
// SAFETY:
// - tcreplica is not null (promised by caller)
// - tcreplica outlives the pointer in this variant (promised by caller)
let tcreplica_ref: &mut TCReplica = TCReplica::from_arg_ref(tcreplica);
let rep_ref = tcreplica_ref.borrow_mut();
TCTask::Mutable(task.into_mut(rep_ref), tcreplica)
Inner::Mutable(task.into_mut(rep_ref), tcreplica)
}
TCTask::Mutable(task, tcreplica) => TCTask::Mutable(task, tcreplica),
TCTask::Invalid => unreachable!(),
Inner::Mutable(task, tcreplica) => Inner::Mutable(task, tcreplica),
Inner::Invalid => unreachable!(),
}
}
/// Make an mutable TCTask into a immutable TCTask. Does nothing if the task
/// is already immutable.
fn to_immut(&mut self) {
*self = match std::mem::replace(self, TCTask::Invalid) {
TCTask::Immutable(task) => TCTask::Immutable(task),
TCTask::Mutable(task, tcreplica) => {
self.inner = match std::mem::replace(&mut self.inner, Inner::Invalid) {
Inner::Immutable(task) => Inner::Immutable(task),
Inner::Mutable(task, tcreplica) => {
// SAFETY:
// - tcreplica is not null (promised by caller of to_mut, which created this
// variant)
// - tcreplica is still alive (promised by caller of to_mut)
let tcreplica_ref: &mut TCReplica = unsafe { TCReplica::from_arg_ref(tcreplica) };
tcreplica_ref.release_borrow();
TCTask::Immutable(task.into_immut())
Inner::Immutable(task.into_immut())
}
TCTask::Invalid => unreachable!(),
Inner::Invalid => unreachable!(),
}
}
}
impl From<Task> for TCTask {
fn from(task: Task) -> TCTask {
TCTask::Immutable(task)
TCTask {
inner: Inner::Immutable(task),
error: None,
}
}
}
/// Utility function to get a shared reference to the underlying Task. All Task getters
/// are error-free, so this does not handle errors.
fn wrap<'a, T, F>(task: *const TCTask, f: F) -> T
fn wrap<'a, T, F>(task: *mut TCTask, f: F) -> T
where
F: FnOnce(&Task) -> T,
{
// SAFETY:
// - task is not null (promised by caller)
// - task outlives 'a (promised by caller)
let tctask: &'a TCTask = unsafe { TCTask::from_arg_ref(task) };
let task: &'a Task = match tctask {
TCTask::Immutable(t) => t,
TCTask::Mutable(t, _) => t.deref(),
TCTask::Invalid => unreachable!(),
let tctask: &'a mut TCTask = unsafe { TCTask::from_arg_ref(task) };
let task: &'a Task = match &tctask.inner {
Inner::Immutable(t) => t,
Inner::Mutable(t, _) => t.deref(),
Inner::Invalid => unreachable!(),
};
tctask.error = None;
f(task)
}
@ -144,16 +145,17 @@ where
// SAFETY:
// - task is not null (promised by caller)
// - task outlives 'a (promised by caller)
let tctask: &'a mut TCTask = unsafe { TCTask::from_arg_ref_mut(task) };
let task: &'a mut TaskMut = match tctask {
TCTask::Immutable(_) => panic!("Task is immutable"),
TCTask::Mutable(ref mut t, _) => t,
TCTask::Invalid => unreachable!(),
let tctask: &'a mut TCTask = unsafe { TCTask::from_arg_ref(task) };
let task: &'a mut TaskMut = match tctask.inner {
Inner::Immutable(_) => panic!("Task is immutable"),
Inner::Mutable(ref mut t, _) => t,
Inner::Invalid => unreachable!(),
};
tctask.error = None;
match f(task) {
Ok(rv) => rv,
Err(e) => {
// TODO: add TCTask error handling, like replica
tctask.error = Some(err_to_tcstring(e));
err_value
}
}
@ -180,7 +182,7 @@ pub extern "C" fn tc_task_to_mut<'a>(task: *mut TCTask, tcreplica: *mut TCReplic
// SAFETY:
// - task is not null (promised by caller)
// - task outlives 'a (promised by caller)
let tctask: &'a mut TCTask = unsafe { TCTask::from_arg_ref_mut(task) };
let tctask: &'a mut TCTask = unsafe { TCTask::from_arg_ref(task) };
// SAFETY:
// - tcreplica is not NULL (promised by caller)
// - tcreplica lives until later call to to_immut via tc_task_to_immut (promised by caller,
@ -198,19 +200,19 @@ pub extern "C" fn tc_task_to_immut<'a>(task: *mut TCTask) {
// SAFETY:
// - task is not null (promised by caller)
// - task outlives 'a (promised by caller)
let tctask: &'a mut TCTask = unsafe { TCTask::from_arg_ref_mut(task) };
let tctask: &'a mut TCTask = unsafe { TCTask::from_arg_ref(task) };
tctask.to_immut();
}
/// Get a task's UUID.
#[no_mangle]
pub extern "C" fn tc_task_get_uuid(task: *const TCTask) -> TCUuid {
pub extern "C" fn tc_task_get_uuid(task: *mut TCTask) -> TCUuid {
wrap(task, |task| task.get_uuid().into())
}
/// Get a task's status.
#[no_mangle]
pub extern "C" fn tc_task_get_status<'a>(task: *const TCTask) -> TCStatus {
pub extern "C" fn tc_task_get_status<'a>(task: *mut TCTask) -> TCStatus {
wrap(task, |task| task.get_status().into())
}
@ -219,7 +221,7 @@ pub extern "C" fn tc_task_get_status<'a>(task: *const TCTask) -> TCStatus {
/// 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<'static> {
pub extern "C" fn tc_task_get_description<'a>(task: *mut TCTask) -> *mut TCString<'static> {
wrap(task, |task| {
let descr: TCString = task.get_description().into();
descr.return_val()
@ -233,7 +235,7 @@ pub extern "C" fn tc_task_get_description<'a>(task: *const TCTask) -> *mut TCStr
/// Check if a task is active (started and not stopped).
#[no_mangle]
pub extern "C" fn tc_task_is_active<'a>(task: *const TCTask) -> bool {
pub extern "C" fn tc_task_is_active<'a>(task: *mut TCTask) -> bool {
wrap(task, |task| task.is_active())
}
@ -349,6 +351,22 @@ pub extern "C" fn tc_task_add_tag<'a>(task: *mut TCTask, tag: *mut TCString) ->
// TODO: tc_task_set_legacy_uda
// TODO: tc_task_remove_legacy_uda
/// Get the latest error for a task, or NULL if the last operation succeeded. Subsequent calls
/// to this function will return NULL. The task pointer must not be NULL. The caller must free the
/// returned string.
#[no_mangle]
pub extern "C" fn tc_task_error<'a>(task: *mut TCTask) -> *mut TCString<'static> {
// SAFETY:
// - task is not null (promised by caller)
// - task outlives 'a (promised by caller)
let task: &'a mut TCTask = unsafe { TCTask::from_arg_ref(task) };
if let Some(tcstring) = task.error.take() {
tcstring.return_val()
} else {
std::ptr::null_mut()
}
}
/// Free a task. The given task must not be NULL. The task must not be used after this function
/// returns, and must not be freed more than once.
///

5
lib/src/util.rs Normal file
View file

@ -0,0 +1,5 @@
use crate::string::TCString;
pub(crate) fn err_to_tcstring(e: impl std::string::ToString) -> TCString<'static> {
TCString::from(e.to_string())
}

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@ -237,23 +237,23 @@ void tc_task_to_immut(struct TCTask *task);
/**
* Get a task's UUID.
*/
struct TCUuid tc_task_get_uuid(const struct TCTask *task);
struct TCUuid tc_task_get_uuid(struct TCTask *task);
/**
* Get a task's status.
*/
enum TCStatus tc_task_get_status(const struct TCTask *task);
enum TCStatus tc_task_get_status(struct TCTask *task);
/**
* 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).
*/
struct TCString *tc_task_get_description(const struct TCTask *task);
struct TCString *tc_task_get_description(struct TCTask *task);
/**
* Check if a task is active (started and not stopped).
*/
bool tc_task_is_active(const struct TCTask *task);
bool tc_task_is_active(struct TCTask *task);
/**
* Set a mutable task's status.
@ -290,6 +290,13 @@ enum TCResult tc_task_stop(struct TCTask *task);
*/
enum TCResult tc_task_add_tag(struct TCTask *task, struct TCString *tag);
/**
* Get the latest error for a task, or NULL if the last operation succeeded. Subsequent calls
* to this function will return NULL. The task pointer must not be NULL. The caller must free the
* returned string.
*/
struct TCString *tc_task_error(struct TCTask *task);
/**
* Free a task. The given task must not be NULL. The task must not be used after this function
* returns, and must not be freed more than once.