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state.rs
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state.rs
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// Copyright (C) 2017-2024 Daniel Mueller ([email protected])
// SPDX-License-Identifier: GPL-3.0-or-later
//! Definitions pertaining UI configuration and task state of the
//! program.
use std::collections::HashSet;
use std::ffi::OsStr;
use std::io::ErrorKind;
use std::path::Path;
use std::rc::Rc;
use anyhow::anyhow;
use anyhow::Context as _;
use anyhow::Result;
use crate::ser::backends::iCal;
use crate::ser::backends::Backend;
use tokio::fs::create_dir_all;
use tokio::fs::read_dir;
use tokio::fs::remove_file;
use tokio::fs::DirEntry;
use tokio::fs::File;
use tokio::fs::OpenOptions;
use tokio::fs::ReadDir;
use tokio::io::AsyncReadExt as _;
use tokio::io::AsyncWriteExt as _;
use uuid::uuid;
use crate::cap::DirCap;
use crate::cap::FileCap;
use crate::cap::WriteGuard;
use crate::ser::state::TaskState as SerTaskState;
use crate::ser::tasks::Id as SerTaskId;
use crate::ser::tasks::Task as SerTask;
use crate::ser::tasks::Tasks as SerTasks;
use crate::ser::tasks::TasksMeta as SerTasksMeta;
use crate::ser::ToSerde;
use crate::tags::Templates;
use crate::tasks::Tasks;
/// The ID we use for storing task meta data.
// We use the "special" UUID 00000000-0000-0000-0000-000000000000 for
// storing task meta data.
const TASKS_META_ID: SerTaskId = uuid!("00000000-0000-0000-0000-000000000000");
/// Load some serialized state from a file.
pub(crate) async fn load_state_from_file<B, T>(path: &Path) -> Result<Option<T>>
where
B: Backend<T>,
{
match File::open(path).await {
Ok(mut file) => {
let mut content = Vec::new();
let _count = file
.read_to_end(&mut content)
.await
.context("failed to read complete file content")?;
let state = B::deserialize(&content).context("failed to decode state")?;
Ok(Some(state))
},
Err(e) if e.kind() == ErrorKind::NotFound => Ok(None),
Err(e) => Err(e).context("error opening file for reading"),
}
}
/// Load a task from a directory entry.
async fn load_task_from_dir_entry(entry: &DirEntry) -> Result<Option<SerTask>> {
let file_name = entry.file_name();
let path = entry.path();
let id = file_name
.to_str()
.and_then(|id| SerTaskId::try_parse(id).ok())
.ok_or_else(|| anyhow!("filename {} is not a valid UUID", path.display()))?;
let result = load_state_from_file::<iCal, SerTask>(&path)
.await
.with_context(|| format!("failed to load state from {}", path.display()))?
.map(|mut task| {
// TODO: Silently overwriting the ID may not be the best choice,
// but it depends on whether it is actually serialized and
// deserialized to begin with. If there is a discrepancy,
// that may indicate a problem. On the other hand, we want
// to give precedence to the file name, because it is the
// most user visible and it would be confusing to not honor
// it.
task.id = id;
task
});
Ok(result)
}
/// Load tasks by iterating over the entries of a `ReadDir` object.
#[allow(clippy::type_complexity)]
async fn load_tasks_from_read_dir(dir: ReadDir) -> Result<(Vec<SerTask>, Option<SerTasksMeta>)> {
let mut dir = dir;
// Ideally we'd size the `Vec` as per the number of directory entries,
// but `fs::ReadDir` does not currently expose that number.
let mut tasks = Vec::new();
let mut tasks_meta = None;
let mut buffer = SerTaskId::encode_buffer();
let tasks_meta_uuid = TASKS_META_ID.as_hyphenated().encode_lower(&mut buffer);
while let Some(entry) = dir
.next_entry()
.await
.context("failed to iterate directory contents")?
{
if entry.file_name() == OsStr::new(tasks_meta_uuid) {
debug_assert_eq!(
tasks_meta, None,
"encountered multiple task meta data files"
);
tasks_meta = load_state_from_file::<iCal, SerTasksMeta>(&entry.path()).await?;
} else if let Some(data) = load_task_from_dir_entry(&entry).await? {
let () = tasks.push(data);
}
}
Ok((tasks, tasks_meta))
}
/// Load tasks from a directory.
///
/// The function assumes that the directory *only* contains files
/// representing tasks (along with one file for meta data).
async fn load_tasks_from_dir(root: &Path) -> Result<SerTaskState> {
let dir = match read_dir(root).await {
Err(e) if e.kind() == ErrorKind::NotFound => return Ok(Default::default()),
result => result,
}?;
let (tasks, tasks_meta) = load_tasks_from_read_dir(dir).await?;
let tasks_meta = tasks_meta.unwrap_or_default();
Ok(SerTaskState {
tasks_meta,
tasks: SerTasks(tasks),
})
}
/// Check whether some state should be saved.
pub(crate) async fn should_save_state<B, T>(file: &Path, state: &T) -> Result<bool>
where
B: Backend<T>,
T: PartialEq,
{
load_state_from_file::<B, T>(file)
.await
.map(|existing| existing.as_ref() != Some(state))
}
/// Save some state into a file.
pub(crate) async fn save_state_to_file<B, T>(file_cap: &mut FileCap<'_>, state: &T) -> Result<()>
where
B: Backend<T>,
T: PartialEq,
{
let path = file_cap.path();
// If in doubt (or in err), always be sure to suggest a save.
if !should_save_state::<B, T>(path, state).await.unwrap_or(true) {
// If the file already contains the expected state there is no need
// for us to write it again.
return Ok(())
}
if let Some(dir) = path.parent() {
let () = create_dir_all(dir).await?;
}
let serialized = B::serialize(state)?;
let () = file_cap
.with_writeable_path(|path| async {
let () = OpenOptions::new()
.create(true)
.truncate(true)
.write(true)
.open(path)
.await?
.write_all(serialized.as_ref())
.await?;
Ok(())
})
.await?;
Ok(())
}
/// Check whether we should save a task.
async fn should_save_task(dir: &Path, task: &SerTask) -> Result<bool> {
let path = dir.join(OsStr::new(&task.id.to_string()));
should_save_state::<iCal, _>(&path, task).await
}
/// Save a task into a file in the given directory.
async fn save_task_to_file(write_guard: &mut WriteGuard<'_>, task: &SerTask) -> Result<()> {
let mut file_cap = write_guard.file_cap(OsStr::new(&task.id.to_string()));
// TODO: It would be better if we were create a temporary file first
// if one already exists and then rename atomically. But even
// nicer would be if we somehow wrapped all saving in a
// transaction of sorts. That would allow us to eliminate the
// chance for *any* inconsistency, e.g., when saving UI
// configuration before task state and the latter failing the
// operation.
save_state_to_file::<iCal, _>(&mut file_cap, task).await
}
/// Check whether we should save some tasks meta state.
async fn should_save_tasks_meta(dir: &Path, tasks_meta: &SerTasksMeta) -> Result<bool> {
let path = dir.join(OsStr::new(&TASKS_META_ID.to_string()));
should_save_state::<iCal, _>(&path, tasks_meta).await
}
/// Save a task meta data into a file in the provided directory.
async fn save_tasks_meta_to_dir(
write_guard: &mut WriteGuard<'_>,
tasks_meta: &SerTasksMeta,
) -> Result<()> {
let mut file_cap = write_guard.file_cap(OsStr::new(&TASKS_META_ID.to_string()));
save_state_to_file::<iCal, _>(&mut file_cap, tasks_meta).await
}
/// Check whether we should save task state.
// TODO: The way we "walk" the task tree is duplicated with
// `save_tasks_to_dir`, but it's unclear how to deduplicate.
async fn should_save_tasks(dir: &Path, tasks: &SerTaskState) -> Result<bool> {
for task in tasks.tasks.0.iter() {
if should_save_task(dir, task).await? {
return Ok(true)
}
}
if should_save_tasks_meta(dir, &tasks.tasks_meta).await? {
return Ok(true)
}
let ids = tasks
.tasks
.0
.iter()
.map(|task| task.id)
.collect::<HashSet<_>>();
// Check whether there are files that do not correspond to a task we
// manage and which should be removed.
let mut dir = read_dir(dir).await?;
while let Some(entry) = dir.next_entry().await? {
let id = entry
.file_name()
.to_str()
.and_then(|id| SerTaskId::try_parse(id).ok());
let remove = if let Some(id) = id {
id != TASKS_META_ID && !ids.contains(&id)
} else {
true
};
if remove {
return Ok(true)
}
}
Ok(false)
}
/// Save tasks into files in the provided directory.
async fn save_tasks_to_dir(dir_cap: &mut DirCap, tasks: &SerTaskState) -> Result<()> {
let mut write_guard = dir_cap.write().await?;
for task in tasks.tasks.0.iter() {
let () = save_task_to_file(&mut write_guard, task).await?;
}
let () = save_tasks_meta_to_dir(&mut write_guard, &tasks.tasks_meta).await?;
let ids = tasks
.tasks
.0
.iter()
.map(|task| task.id)
.collect::<HashSet<_>>();
// Remove all files that do not correspond to an ID we just saved.
let mut dir = read_dir(write_guard.path()).await?;
while let Some(entry) = dir.next_entry().await? {
let id = entry
.file_name()
.to_str()
.and_then(|id| SerTaskId::try_parse(id).ok());
let remove = if let Some(id) = id {
id != TASKS_META_ID && !ids.contains(&id)
} else {
true
};
if remove {
// Note that we purposefully do not support the case of having a
// directory inside the root directory, as we'd never create one
// there programmatically.
let () = remove_file(entry.path()).await?;
}
}
Ok(())
}
/// A struct encapsulating the task state of the program.
#[derive(Debug)]
pub struct TaskState {
/// The shared templates usable by all tasks.
templates: Rc<Templates>,
/// The shared task database.
tasks: Rc<Tasks>,
}
impl TaskState {
/// Load `TaskState` from a directory.
pub async fn load(tasks_root: &Path) -> Result<Self> {
let task_state = load_tasks_from_dir(tasks_root).await.with_context(|| {
format!(
"failed to load tasks from directory {}",
tasks_root.display()
)
})?;
let templates = Templates::with_serde(task_state.tasks_meta.templates)
.map_err(|id| anyhow!("encountered duplicate tag ID {}", id))?;
let templates = Rc::new(templates);
let tasks = Tasks::with_serde(task_state.tasks, Rc::clone(&templates))
.context("failed to instantiate task database")?;
let tasks = Rc::new(tasks);
let slf = Self { templates, tasks };
Ok(slf)
}
/// Create a `TaskState` object from serialized state.
pub fn with_serde(state: SerTaskState) -> Result<Self> {
let templates = Templates::with_serde(state.tasks_meta.templates)
.map_err(|id| anyhow!("encountered duplicate tag ID {}", id))?;
let templates = Rc::new(templates);
let tasks = Tasks::with_serde(state.tasks, Rc::clone(&templates))
.context("failed to instantiate task database")?;
let slf = Self {
templates,
tasks: Rc::new(tasks),
};
Ok(slf)
}
/// Check whether any of the tasks were changed from the state in the
/// given `root_dir`.
pub async fn is_changed(&self, root_dir: &Path) -> bool {
should_save_tasks(root_dir, &self.to_serde())
.await
.unwrap_or(true)
}
/// Persist the state into a file.
pub async fn save(&self, root_dir_cap: &mut DirCap) -> Result<()> {
save_tasks_to_dir(root_dir_cap, &self.to_serde()).await
}
/// Retrieve the `Templates` object associated with this `TaskState`
/// object.
pub fn templates(&self) -> &Rc<Templates> {
&self.templates
}
/// Retrieve the `Tasks` object associated with this `TaskState`
/// object.
pub fn tasks(&self) -> &Rc<Tasks> {
&self.tasks
}
}
impl ToSerde for TaskState {
type Output = SerTaskState;
/// Convert this object into a serializable one.
fn to_serde(&self) -> Self::Output {
SerTaskState {
tasks_meta: SerTasksMeta {
templates: self.templates.to_serde(),
},
tasks: self.tasks.to_serde(),
}
}
}
#[cfg(test)]
pub mod tests {
use super::*;
use std::env::temp_dir;
use tempfile::TempDir;
use tokio::fs::remove_dir_all;
use tokio::test;
use crate::ser::backends::Json;
use crate::ser::tags::Id as SerId;
use crate::ser::tags::Tag as SerTag;
use crate::ser::tags::Template as SerTemplate;
use crate::ser::tags::Templates as SerTemplates;
use crate::test::make_tasks;
/// Create a `TaskState` object.
fn make_task_state(tasks: Vec<SerTask>) -> TaskState {
let task_state = SerTaskState {
tasks_meta: Default::default(),
tasks: SerTasks::from(tasks),
};
let task_state = TaskState::with_serde(task_state).unwrap();
task_state
}
/// Check that we can save tasks into a directory and load them back
/// from there.
#[test]
async fn save_load_tasks() {
async fn test(root: &Path, tasks: Vec<SerTask>, templates: Option<SerTemplates>) {
let task_state = SerTaskState {
tasks_meta: SerTasksMeta {
templates: templates.unwrap_or_default(),
},
tasks: SerTasks::from(tasks),
};
let task_state = TaskState::with_serde(task_state).unwrap().to_serde();
let mut tasks_root_cap = DirCap::for_dir(root.to_path_buf()).await.unwrap();
let () = save_tasks_to_dir(&mut tasks_root_cap, &task_state)
.await
.unwrap();
let mut loaded = load_tasks_from_dir(root).await.unwrap();
// The order of tasks is undefined at this point of the loading
// process. Sort them according to their position as is done
// internally by `TaskState`.
let () = loaded.tasks.0.sort_by(|first, second| {
let first = first.position.unwrap_or(f64::MAX);
let second = second.position.unwrap_or(f64::MAX);
first.total_cmp(&second)
});
assert_eq!(loaded, task_state);
}
// Note that we use a single temporary directory here for all tests.
// Doing so tests that the task saving logic removes files of tasks
// that have been deleted.
let root = TempDir::new().unwrap();
let tasks = Vec::new();
// Check that things work out even when no task is provided.
let () = test(root.path(), tasks, None).await;
let tasks = make_tasks(3);
let () = test(root.path(), tasks, None).await;
let id_tag = SerId::try_from(42).unwrap();
let templates = SerTemplates(vec![SerTemplate {
id: id_tag,
name: "tag1".to_string(),
}]);
// Test with a task with a tag as well.
let tasks = vec![SerTask::new("a task!").with_tags([SerTag { id: id_tag }])];
let () = test(root.path(), tasks, Some(templates)).await;
let tasks = make_tasks(25);
// Make sure that directories not yet present are created.
let () = test(
&root.path().join("not").join("yet").join("present"),
tasks,
None,
)
.await;
}
/// Test that saving tasks and loading them back preserves their
/// positions.
#[test]
async fn save_load_preserves_positions() {
let root = TempDir::new().unwrap();
let root = root.path();
let mut task_vec = make_tasks(4);
task_vec[0].position = Some(-42.0);
task_vec[1].position = Some(0.0);
task_vec[2].position = Some(10.0);
task_vec[3].position = Some(10.001);
let task_state = SerTaskState {
tasks_meta: SerTasksMeta::default(),
tasks: SerTasks::from(task_vec.clone()),
};
let task_state = TaskState::with_serde(task_state).unwrap();
let mut tasks_root_cap = DirCap::for_dir(root.to_path_buf()).await.unwrap();
let () = task_state.save(&mut tasks_root_cap).await.unwrap();
let mut task_state = load_tasks_from_dir(root).await.unwrap();
let () = task_state.tasks.0.sort_by(|first, second| {
let first = first.position.unwrap_or(f64::MAX);
let second = second.position.unwrap_or(f64::MAX);
first.total_cmp(&second)
});
assert_eq!(task_state.tasks.0, task_vec);
}
/// Check that IDs are preserved when serializing and deserializing
/// again.
#[test]
async fn loaded_tasks_use_saved_ids() {
let root = TempDir::new().unwrap();
let root = root.path();
let tasks = make_tasks(15);
let task_state = SerTaskState {
tasks_meta: SerTasksMeta::default(),
tasks: SerTasks::from(tasks),
};
let task_state = TaskState::with_serde(task_state).unwrap();
let tasks = {
let tasks = task_state.tasks();
let (task1, task2, task3) = tasks.iter(|mut iter| {
// Remove the first three tasks. If IDs were to not be preserved
// on serialization, the IDs of these tasks would (likely) be
// reassigned again to others on load and we would fail below.
let task1 = Rc::clone(iter.next().unwrap());
let task2 = Rc::clone(iter.next().unwrap());
let task3 = Rc::clone(iter.next().unwrap());
(task1, task2, task3)
});
let () = tasks.remove(task1);
let () = tasks.remove(task2);
let () = tasks.remove(task3);
tasks.iter(|iter| iter.cloned().collect::<Vec<_>>())
};
let mut tasks_root_cap = DirCap::for_dir(root.to_path_buf()).await.unwrap();
let () = task_state.save(&mut tasks_root_cap).await.unwrap();
let task_state = load_tasks_from_dir(root).await.unwrap();
let templates = Rc::new(Templates::with_serde(task_state.tasks_meta.templates).unwrap());
let loaded = Tasks::with_serde(task_state.tasks, templates).unwrap();
let loaded = loaded.iter(|iter| iter.cloned().collect::<Vec<_>>());
let () = tasks
.iter()
.zip(loaded.iter())
.map(|(task, loaded)| assert_eq!(task.id(), loaded.id()))
.for_each(|_| ());
}
/// Check that `save_state_to_file` correctly creates non-existing
/// directories.
#[test]
async fn create_dirs_for_state() {
let base = temp_dir().join("dir1");
let dir = base.join("dir2");
let mut dir_cap = DirCap::for_dir(dir.clone()).await.unwrap();
let file = OsStr::new("file");
let write_guard = dir_cap.write().await.unwrap();
let mut file_cap = write_guard.file_cap(file);
let () = save_state_to_file::<Json, _>(&mut file_cap, &42)
.await
.unwrap();
let mut file = File::open(dir.join(file)).await.unwrap();
let mut content = Vec::new();
let _count = file.read_to_end(&mut content).await.unwrap();
let () = remove_dir_all(&base).await.unwrap();
assert_eq!(content, b"42")
}
/// Check that we can save a `TaskState` and load it back.
#[test]
async fn save_and_load_task_state() {
let task_vec = make_tasks(3);
let task_state = make_task_state(task_vec.clone());
let tasks_dir = TempDir::new().unwrap();
let mut tasks_root_cap = DirCap::for_dir(tasks_dir.path().to_path_buf())
.await
.unwrap();
let () = task_state.save(&mut tasks_root_cap).await.unwrap();
let new_task_state = TaskState::load(tasks_dir.path()).await.unwrap();
let new_task_vec = new_task_state.to_serde().tasks.into_task_vec();
assert_eq!(new_task_vec, task_vec);
}
/// Verify that loading a `TaskState` object succeeds even if the
/// directory to load from is not present.
#[test]
async fn load_task_state_file_not_found() {
let tasks_root = {
let task_vec = make_tasks(1);
let task_state = make_task_state(task_vec.clone());
let tasks_dir = TempDir::new().unwrap();
let mut tasks_root_cap = DirCap::for_dir(tasks_dir.path().to_path_buf())
.await
.unwrap();
let () = task_state.save(&mut tasks_root_cap).await.unwrap();
tasks_dir.path().to_path_buf()
};
// The files are removed by now, so we can test that both kinds of
// state handle such missing files gracefully.
let new_task_state = TaskState::load(&tasks_root).await.unwrap();
let new_task_vec = new_task_state.to_serde().tasks.into_task_vec();
assert_eq!(new_task_vec, Vec::new());
}
/// Test that we fail `TaskState` construction when an invalid tag is
/// encountered.
#[test]
async fn load_state_with_invalid_tag() {
let tasks = vec![SerTask::new("a task!").with_tags([SerTag {
id: SerId::try_from(42).unwrap(),
}])];
let task_state = SerTaskState {
tasks_meta: Default::default(),
tasks: SerTasks::from(tasks),
};
let err = TaskState::with_serde(task_state).unwrap_err();
assert_eq!(
err.root_cause().to_string(),
"encountered invalid tag ID 42"
)
}
/// Check that we can correctly instantiate a `TaskState` object from
/// serialized state.
#[test]
async fn load_state() {
let id_tag1 = SerId::try_from(29).unwrap();
let id_tag2 = SerId::try_from(1337 + 42 - 1).unwrap();
let templates = SerTemplates(vec![
SerTemplate {
id: id_tag1,
name: "tag1".to_string(),
},
SerTemplate {
id: id_tag2,
name: "tag2".to_string(),
},
]);
let tasks = vec![
SerTask::new("a task!").with_tags([SerTag { id: id_tag2 }]),
SerTask::new("an untagged task"),
SerTask::new("a tag1 task").with_tags([SerTag { id: id_tag1 }]),
SerTask::new("a doubly tagged task")
.with_tags([SerTag { id: id_tag2 }, SerTag { id: id_tag1 }]),
];
let task_state = SerTaskState {
tasks_meta: SerTasksMeta { templates },
tasks: SerTasks::from(tasks),
};
let state = TaskState::with_serde(task_state).unwrap();
let tasks = state.tasks;
let vec = tasks.iter(|iter| iter.cloned().collect::<Vec<_>>());
let mut it = vec.iter();
let task1 = it.next().unwrap();
let () = task1.tags(|mut iter| {
assert_eq!(iter.next().unwrap().name(), "tag2");
assert!(iter.next().is_none());
});
let task2 = it.next().unwrap();
assert!(task2.tags(|mut iter| iter.next().is_none()));
let task3 = it.next().unwrap();
let () = task3.tags(|mut iter| {
assert_eq!(iter.next().unwrap().name(), "tag1");
assert!(iter.next().is_none());
});
let task4 = it.next().unwrap();
let () = task4.tags(|mut iter| {
assert!(iter.next().is_some());
assert!(iter.next().is_some());
assert!(iter.next().is_none());
});
}
}