updates, clippy, formatting

[Mitarbeiter/Tim-Zeitz/stud-rust-base.git] / src / io.rs

diff --git a/src/io.rs b/src/io.rs
index 489d9e086280f270e98a8e01e7fbb86ca6a88fa4..3c4d73276be9e703cc68245f50e37cddb695bf57 100644 (file)
--- a/src/io.rs
+++ b/src/io.rs
@@ -1,15 +1,44 @@
-use std::fs;
-use std::fs::File;
-use std::io::prelude::*;
-use std::io::Result;
-use std::mem;
-use std::slice;
+//! This module contains a few traits and blanket implementations
+//! for (de)serializing and writing/reading data to/from the disc.
+//! To use it you should import the `Load` and `Store` traits and use the
+//! `load_from` and `write_to` methods.
+//!
+//! # Example
+//!
+//! ```no_run
+//! # use stud_rust_base::io::*;
+//!
+//! let head = Vec::<u32>::load_from("head_file_name")?;
+//! let lat = Vec::<f32>::load_from("node_latitude_file_name")?;
+//! head.write_to(&"output_file")?;
+//! # Ok::<(), Box<dyn std::error::Error>>(())
+//! ```
 
+use std::{
+    fs::{metadata, File},
+    io::{prelude::*, Result},
+    mem,
+    path::Path,
+    slice,
+};
+
+/// A trait which allows accessing the data of an object as a slice of bytes.
+/// The bytes should represent a serialization of the object and allow
+/// recreating it when reading these bytes again from the disk.
+///
+/// Do not use this Trait but rather the `Store` trait.
 pub trait DataBytes {
+    /// Should return the serialized object as a slice of bytes
     fn data_bytes(&self) -> &[u8];
 }
 
+/// A trait which mutably exposes the internal data of an object so that
+/// a serialized object can be loaded from disk and written back into a precreated
+/// object of the right size.
+///
+/// Do not use this Trait but rather the `Load` trait.
 pub trait DataBytesMut {
+    /// Should return a mutable slice of the internal data of the object
     fn data_bytes_mut(&mut self) -> &mut [u8];
 }
 
@@ -20,6 +49,12 @@ impl<T: Copy> DataBytes for [T] {
     }
 }
 
+impl<T: Copy> DataBytes for Vec<T> {
+    fn data_bytes(&self) -> &[u8] {
+        self[..].data_bytes()
+    }
+}
+
 impl<T: Copy> DataBytesMut for [T] {
     fn data_bytes_mut(&mut self) -> &mut [u8] {
         let num_bytes = self.len() * mem::size_of::<T>();
@@ -34,21 +69,28 @@ impl<T: Copy> DataBytesMut for Vec<T> {
     }
 }
 
-pub trait Store : DataBytes {
-    fn write_to(&self, filename: &str) -> Result<()> {
-        File::create(filename)?.write_all(self.data_bytes())
+/// A trait which extends the `DataBytes` trait and exposes a method to write objects to disk.
+pub trait Store: DataBytes {
+    /// Writes the serialized object to the file with the given path
+    fn write_to(&self, path: &dyn AsRef<Path>) -> Result<()> {
+        File::create(path)?.write_all(self.data_bytes())
     }
 }
 
 impl<T: DataBytes> Store for T {}
 impl<T> Store for [T] where [T]: DataBytes {}
 
-pub trait Load : DataBytesMut + Sized {
+/// A trait to load serialized data back into objects.
+pub trait Load: DataBytesMut + Sized {
+    /// This method must create an object of the correct size for serialized data with the given number of bytes.
+    /// It should not be necessary to call this method directly.
     fn new_with_bytes(num_bytes: usize) -> Self;
 
-    fn load_from(filename: &str) -> Result<Self> {
-        let metadata = fs::metadata(filename)?;
-        let mut file = File::open(filename)?;
+    /// This method will load serialized data from the disk, create an object of the appropriate size,
+    /// deserialize the bytes into the object and return the object.
+    fn load_from<P: AsRef<Path>>(path: P) -> Result<Self> {
+        let metadata = metadata(path.as_ref())?;
+        let mut file = File::open(path)?;
 
         let mut object = Self::new_with_bytes(metadata.len() as usize);
         assert_eq!(metadata.len() as usize, object.data_bytes_mut().len());