Process initiator working

bffhd/utils/linebuffer.rs

@@ -0,0 +1,60 @@
+use std::ops::{Deref, DerefMut};
+
+pub struct LineBuffer {
+    buffer: Vec<u8>,
+    valid: usize,
+}
+
+impl LineBuffer {
+    pub fn new() -> Self {
+        Self {
+            buffer: Vec::new(),
+            valid: 0,
+        }
+    }
+
+    /// Resize the internal Vec so that buffer.len() == buffer.capacity()
+    fn resize(&mut self) {
+        // SAFETY: Whatever is in memory is always valid as u8.
+        unsafe { self.buffer.set_len(self.buffer.capacity()) }
+    }
+
+    /// Get an (initialized but empty) writeable buffer of at least `atleast` bytes
+    pub fn get_mut_write(&mut self, atleast: usize) -> &mut [u8] {
+        let avail = self.buffer.len() - self.valid;
+        if avail < atleast {
+            self.buffer.reserve(atleast - avail);
+            self.resize()
+        }
+        &mut self.buffer[self.valid..]
+    }
+
+    pub fn advance_valid(&mut self, amount: usize) {
+        self.valid += amount
+    }
+
+    /// Mark `amount` bytes as 'consumed'
+    ///
+    /// This will move any remaining data to the start of the buffer for future processing
+    pub fn consume(&mut self, amount: usize) {
+        assert!(amount <= self.valid);
+
+        if amount < self.valid {
+            self.buffer.copy_within(amount..self.valid, 0);
+        }
+        self.valid -= amount;
+    }
+}
+
+impl Deref for LineBuffer {
+    type Target = [u8];
+
+    fn deref(&self) -> &Self::Target {
+        &self.buffer[0..self.valid]
+    }
+}
+impl DerefMut for LineBuffer {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.buffer[0..self.valid]
+    }
+}

bffhd/utils/mod.rs

@@ -8,3 +8,5 @@ pub mod varint;
 pub mod l10nstring;
 
 pub mod uuid;
+
+pub mod linebuffer;