vec: rework part 2

crates/brk_vec/src/traits/generic.rs

@@ -0,0 +1,194 @@
+use std::{
+    fs::{File, OpenOptions},
+    io::{self, Seek, SeekFrom, Write},
+    path::{Path, PathBuf},
+    sync::Arc,
+};
+
+use arc_swap::{ArcSwap, Guard};
+use axum::{
+    Json,
+    response::{IntoResponse, Response},
+};
+use memmap2::Mmap;
+
+use crate::{Error, Result, Version};
+
+use super::{DynamicVec, StoredIndex, StoredType};
+
+pub trait GenericVec<I, T>: DynamicVec<I = I, T = T>
+where
+    I: StoredIndex,
+    T: StoredType,
+{
+    const SIZE_OF_T: usize = size_of::<Self::T>();
+
+    fn open_file(&self) -> io::Result<File> {
+        Self::open_file_(&self.path_vec())
+    }
+    fn open_file_(path: &Path) -> io::Result<File> {
+        OpenOptions::new()
+            .read(true)
+            .create(true)
+            .truncate(false)
+            .append(true)
+            .open(path)
+    }
+
+    fn file_set_len(&mut self, len: u64) -> Result<()> {
+        let mut file = self.open_file()?;
+        file.set_len(len)?;
+        file.seek(SeekFrom::End(0))?;
+        self.update_mmap(file)
+    }
+
+    fn file_write_all(&mut self, buf: &[u8]) -> Result<()> {
+        let mut file = self.open_file()?;
+        file.write_all(buf)?;
+        self.update_mmap(file)
+    }
+
+    #[inline]
+    fn reset(&mut self) -> Result<()> {
+        self.file_write_all(&[])?;
+        Ok(())
+    }
+
+    fn mmap(&self) -> &ArcSwap<Mmap>;
+
+    #[inline]
+    fn new_guard(&self) -> Guard<Arc<Mmap>> {
+        self.mmap().load()
+    }
+    fn guard(&self) -> &Option<Guard<Arc<Mmap>>>;
+    fn mut_guard(&mut self) -> &mut Option<Guard<Arc<Mmap>>>;
+
+    fn new_mmap(file: File) -> Result<Arc<Mmap>> {
+        Ok(Arc::new(unsafe { Mmap::map(&file)? }))
+    }
+
+    fn update_mmap(&mut self, file: File) -> Result<()> {
+        file.sync_all()?;
+        let mmap = Self::new_mmap(file)?;
+        self.mmap().store(mmap);
+        if self.guard().is_some() {
+            let guard = self.new_guard();
+            self.mut_guard().replace(guard);
+        } else {
+            unreachable!()
+        }
+        Ok(())
+    }
+
+    #[inline]
+    fn is_pushed_empty(&self) -> bool {
+        self.pushed_len() == 0
+    }
+
+    #[inline]
+    fn index_to_pushed_index(&self, index: usize) -> Result<Option<usize>> {
+        let stored_len = self.stored_len();
+
+        if index >= stored_len {
+            let index = index - stored_len;
+            if index >= self.pushed_len() {
+                Err(Error::IndexTooHigh)
+            } else {
+                Ok(Some(index))
+            }
+        } else {
+            Err(Error::IndexTooLow)
+        }
+    }
+
+    #[inline]
+    fn has(&self, index: Self::I) -> Result<bool> {
+        Ok(self.has_(index.to_usize()?))
+    }
+    #[inline]
+    fn has_(&self, index: usize) -> bool {
+        index < self.len()
+    }
+
+    #[inline]
+    fn index_type_to_string(&self) -> &str {
+        Self::I::to_string()
+    }
+
+    #[inline]
+    fn iter<F>(&mut self, f: F) -> Result<()>
+    where
+        F: FnMut(
+            (
+                Self::I,
+                Self::T,
+                &mut dyn DynamicVec<I = Self::I, T = Self::T>,
+            ),
+        ) -> Result<()>,
+    {
+        self.iter_from(Self::I::default(), f)
+    }
+
+    fn iter_from<F>(&mut self, index: Self::I, f: F) -> Result<()>
+    where
+        F: FnMut(
+            (
+                Self::I,
+                Self::T,
+                &mut dyn DynamicVec<I = Self::I, T = Self::T>,
+            ),
+        ) -> Result<()>;
+
+    fn fix_i64(i: i64, len: usize, from: bool) -> usize {
+        if i >= 0 {
+            let v = i as usize;
+            if v < len {
+                v
+            } else if from {
+                len - 1
+            } else {
+                len
+            }
+        } else {
+            let v = len as i64 + i;
+            if v < 0 { 0 } else { v as usize }
+        }
+    }
+
+    fn flush(&mut self) -> Result<()>;
+
+    fn truncate_if_needed(&mut self, index: Self::I) -> Result<()>;
+
+    fn collect_range(&self, from: Option<i64>, to: Option<i64>) -> Result<Json<Vec<Self::T>>>;
+
+    fn collect_range_response(&self, from: Option<i64>, to: Option<i64>) -> Result<Response> {
+        Ok(self.collect_range(from, to)?.into_response())
+    }
+
+    fn path(&self) -> &Path;
+
+    #[inline]
+    fn path_vec(&self) -> PathBuf {
+        Self::path_vec_(self.path())
+    }
+    #[inline]
+    fn path_vec_(path: &Path) -> PathBuf {
+        path.join("vec")
+    }
+
+    #[inline]
+    fn path_version_(path: &Path) -> PathBuf {
+        path.join("version")
+    }
+
+    fn file_name(&self) -> String {
+        self.path()
+            .file_name()
+            .unwrap()
+            .to_str()
+            .unwrap()
+            .to_owned()
+    }
+
+    fn version(&self) -> Version;
+}