brk: first commit

_src/parser/databases/metadata.rs

@@ -0,0 +1,127 @@
+use allocative::Allocative;
+use bincode::{Decode, Encode};
+use color_eyre::eyre::eyre;
+use serde::{Deserialize, Serialize};
+use std::{
+    fmt::Debug,
+    fs, io,
+    ops::{Deref, DerefMut},
+    path::{Path, PathBuf},
+};
+
+use crate::{
+    io::Serialization,
+    structs::{Counter, Date, Height},
+};
+
+#[derive(Default, Debug, Encode, Decode, Allocative)]
+pub struct Metadata {
+    path: PathBuf,
+    data: MetadataData,
+}
+
+impl Deref for Metadata {
+    type Target = MetadataData;
+
+    fn deref(&self) -> &Self::Target {
+        &self.data
+    }
+}
+
+impl DerefMut for Metadata {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.data
+    }
+}
+
+impl Metadata {
+    pub fn import(path: &Path, version: u16) -> Self {
+        Self {
+            data: MetadataData::import(path, version),
+            path: path.to_owned(),
+        }
+    }
+
+    pub fn export(&mut self, height: Height, date: Date) -> color_eyre::Result<()> {
+        if self.last_height.unwrap_or_default() < height {
+            self.last_height.replace(height);
+        }
+
+        if self.last_date.unwrap_or_default() < date {
+            self.last_date.replace(date);
+        }
+
+        self.data.export(&self.path)
+    }
+
+    pub fn reset(&mut self) {
+        let _ = self.data.reset(&self.path);
+    }
+
+    pub fn called_insert(&mut self) {
+        self.serial += 1;
+        self.len.increment();
+    }
+
+    pub fn called_remove(&mut self) {
+        self.len.decrement();
+    }
+
+    pub fn check_if_in_sync(&self, other: &Self) -> bool {
+        self.last_date == other.last_date && self.last_height == other.last_height
+    }
+
+    pub fn check_farer_or_in_sync(&self, other: &Self) -> bool {
+        self.last_date >= other.last_date && self.last_height >= other.last_height
+    }
+}
+
+#[derive(Default, Debug, Encode, Decode, Serialize, Deserialize, Allocative)]
+pub struct MetadataData {
+    version: u16,
+    pub serial: usize,
+    pub len: Counter,
+    pub last_height: Option<Height>,
+    pub last_date: Option<Date>,
+}
+
+impl MetadataData {
+    fn full_path(folder_path: &Path) -> PathBuf {
+        folder_path.join("metadata")
+    }
+
+    pub fn import(path: &Path, version: u16) -> Self {
+        let mut s = Self::_import(path, version).unwrap_or_default();
+        s.version = version;
+        s
+    }
+
+    fn _import(path: &Path, version: u16) -> color_eyre::Result<Self> {
+        fs::create_dir_all(path)?;
+
+        let s: MetadataData = Serialization::Binary.import(&Self::full_path(path))?;
+
+        if s.version != version {
+            return Err(eyre!("Bad version"));
+        }
+
+        Ok(s)
+    }
+
+    pub fn export(&self, path: &Path) -> color_eyre::Result<()> {
+        Serialization::Binary.export(Path::new(&Self::full_path(path)), self)
+    }
+
+    pub fn reset(&mut self, path: &Path) -> color_eyre::Result<(), io::Error> {
+        self.clear();
+
+        fs::remove_file(Self::full_path(path))
+    }
+
+    fn clear(&mut self) {
+        self.serial = 0;
+        self.len.reset();
+        self.last_height = None;
+        self.last_date = None;
+    }
+}