From 43e1a12b5bce11b4a28a53acca243e35c2be6d3e Mon Sep 17 00:00:00 2001
From: evuez <julien@mulga.net>
Date: Wed, 3 Apr 2024 22:43:16 +0200
Subject: Initial commit

---
 src/client/fs/fh.rs | 110 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 src/client/fs/fh.rs

(limited to 'src/client/fs/fh.rs')

diff --git a/src/client/fs/fh.rs b/src/client/fs/fh.rs
new file mode 100644
index 0000000..b1e8739
--- /dev/null
+++ b/src/client/fs/fh.rs
@@ -0,0 +1,110 @@
+use crate::{common::temp_file, server::Stream};
+use log::error;
+use std::{
+    fs::{self, File},
+    io::{BufReader, BufWriter, Read, Seek, SeekFrom, Write},
+    ops::Index,
+    path::PathBuf,
+    slice::SliceIndex,
+};
+
+pub struct FileHandle {
+    buffer: Vec<u8>,
+    size: usize,
+    tmp: Option<(PathBuf, BufWriter<File>)>,
+    reader: Option<BufReader<File>>,
+    dirty: bool,
+}
+
+impl FileHandle {
+    pub fn empty() -> std::io::Result<Self> {
+        let (temp_path, temp_file) = temp_file()?;
+
+        Ok(Self {
+            buffer: Vec::new(),
+            size: 0,
+            tmp: Some((temp_path, BufWriter::new(temp_file))),
+            reader: None,
+            dirty: false,
+        })
+    }
+
+    pub fn new_rw(reader: BufReader<File>) -> std::io::Result<Self> {
+        // TODO: Copy read to tmp
+        let (temp_path, temp_file) = temp_file()?;
+
+        Ok(Self {
+            buffer: Vec::new(),
+            size: 0,
+            tmp: Some((temp_path, BufWriter::new(temp_file))),
+            reader: Some(reader),
+            dirty: false,
+        })
+    }
+
+    pub fn new_ro(reader: BufReader<File>) -> Self {
+        Self {
+            buffer: Vec::new(),
+            size: 0,
+            tmp: None,
+            reader: Some(reader),
+            dirty: false,
+        }
+    }
+
+    pub fn is_dirty(&self) -> bool {
+        self.dirty
+    }
+
+    pub fn write(&mut self, data: &[u8], offset: usize) -> Option<usize> {
+        let Some((_, ref mut tmp)) = self.tmp else {
+            error!("Tried to write to a RO file handle");
+            return None;
+        };
+
+        tmp.seek(SeekFrom::Start(offset as u64))
+            .inspect_err(|e| error!("Seek error: {e}"))
+            .ok()?;
+        let written = tmp
+            .write(data)
+            .inspect_err(|e| error!("Write error: {e}"))
+            .ok()?;
+
+        self.dirty = true;
+
+        Some(written)
+    }
+
+    pub fn read(&mut self, offset: usize, size: usize) -> Vec<u8> {
+        let Some(mut reader) = self.reader else {
+            error!("Tried to read from an empty file handle");
+            return Vec::new();
+        };
+
+        let mut buf = Vec::with_capacity(size);
+
+        // TODO: error handling...
+        reader.seek(SeekFrom::Start(offset as u64)).unwrap();
+        reader.read_exact(&mut buf).unwrap();
+
+        buf
+    }
+
+    pub fn clear(&mut self) {
+        self.tmp.as_mut().map(|b| b.1.flush());
+        self.buffer.clear();
+        self.dirty = false;
+    }
+}
+
+impl Drop for FileHandle {
+    fn drop(&mut self) {
+        let Some((ref temp_path, _)) = self.tmp else {
+            return;
+        };
+
+        if let Err(e) = fs::remove_file(temp_path) {
+            error!("Couldn't delete temp file {temp_path:?}: {e}");
+        }
+    }
+}
-- 
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