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pub mod engines; pub mod prelude { pub use super::{engines::prelude::*, engines::*}; } use crate::{id::ID, Scalar}; use std::{ mem::replace, sync::{Arc, Mutex}, }; pub type FetchProcessID = ID<FetchProcess>; #[derive(Debug, PartialEq, Copy, Clone)] pub enum FetchCancelReason { User, Error, } #[derive(Debug, PartialEq, Copy, Clone)] pub enum FetchStatus { Empty, InProgress(Scalar), Done, Canceled(FetchCancelReason), Read, } pub trait FetchProcessReader: Send + Sync { fn status(&self) -> FetchStatus; fn read(&self) -> Option<Vec<u8>>; fn byte_size(&self) -> Option<usize>; fn box_clone(&self) -> Box<dyn FetchProcessReader>; } impl Clone for Box<dyn FetchProcessReader> { fn clone(&self) -> Self { self.box_clone() } } #[derive(Clone)] pub struct FetchProcess { id: FetchProcessID, inner: Arc<Mutex<(FetchStatus, Option<Vec<u8>>)>>, } impl Default for FetchProcess { fn default() -> Self { Self::new() } } impl FetchProcess { #[inline] pub fn new() -> Self { Self { id: FetchProcessID::new(), inner: Arc::new(Mutex::new((FetchStatus::Empty, None))), } } #[inline] pub fn new_start() -> Self { Self { id: FetchProcessID::new(), inner: Arc::new(Mutex::new((FetchStatus::InProgress(0.0), None))), } } #[inline] pub fn new_done(data: Vec<u8>) -> Self { Self { id: FetchProcessID::new(), inner: Arc::new(Mutex::new((FetchStatus::Done, Some(data)))), } } #[inline] pub fn new_cancel(reason: FetchCancelReason) -> Self { Self { id: FetchProcessID::new(), inner: Arc::new(Mutex::new((FetchStatus::Canceled(reason), None))), } } #[inline] pub fn id(&self) -> FetchProcessID { self.id } pub fn start(&mut self) { if let Ok(mut meta) = self.inner.lock() { *meta = (FetchStatus::InProgress(0.0), None); } } pub fn progress(&mut self, value: Scalar) { if let Ok(mut meta) = self.inner.lock() { *meta = (FetchStatus::InProgress(value), None); } } pub fn done(&mut self, data: Vec<u8>) { if let Ok(mut meta) = self.inner.lock() { *meta = (FetchStatus::Done, Some(data)); } } pub fn cancel(&mut self, reason: FetchCancelReason) { if let Ok(mut meta) = self.inner.lock() { *meta = (FetchStatus::Canceled(reason), None); } } pub fn readers_count(&self) -> usize { Arc::strong_count(&self.inner) + Arc::weak_count(&self.inner) - 1 } } impl FetchProcessReader for FetchProcess { fn status(&self) -> FetchStatus { if let Ok(meta) = self.inner.lock() { meta.0 } else { FetchStatus::Empty } } fn read(&self) -> Option<Vec<u8>> { if let Ok(mut meta) = self.inner.lock() { if meta.0 == FetchStatus::Done { let old: (FetchStatus, Option<Vec<u8>>) = replace(&mut meta, (FetchStatus::Read, None)); return old.1; } } None } fn byte_size(&self) -> Option<usize> { if let Ok(meta) = self.inner.lock() { if meta.0 == FetchStatus::Done { if let Some(bytes) = &meta.1 { return Some(bytes.len()); } } } None } fn box_clone(&self) -> Box<dyn FetchProcessReader> { Box::new((*self).clone()) } } pub trait FetchEngine: Send + Sync { fn fetch(&mut self, path: &str) -> Result<Box<dyn FetchProcessReader>, FetchStatus>; fn cancel(&mut self, reader: Box<dyn FetchProcessReader>) { #[allow(clippy::cast_ptr_alignment)] let ptr = Box::into_raw(reader) as *mut FetchProcess; unsafe { (*ptr).cancel(FetchCancelReason::User); Box::from_raw(ptr); } } } #[cfg(test)] mod tests { #[test] #[cfg(not(feature = "web"))] fn test_general() { let mut engine = engines::fs::FsFetchEngine::new(&"."); let reader = engine.fetch("Cargo.toml").unwrap(); let reader2 = reader.clone(); #[cfg(feature = "parallel")] { assert_eq!(reader.status(), FetchStatus::InProgress(0.0)); assert_eq!(reader2.status(), FetchStatus::InProgress(0.0)); } loop { match reader.status() { FetchStatus::InProgress(_) => continue, _ => break, } } assert_eq!(reader.status(), FetchStatus::Done); assert_eq!(reader2.status(), FetchStatus::Done); assert!(!reader.read().unwrap().is_empty()); assert_eq!(reader.status(), FetchStatus::Empty); assert_eq!(reader2.status(), FetchStatus::Empty); drop(reader); drop(reader2); } }