From fffd27abb3b3e1cbe0a4236ee68be5bf6588a20c Mon Sep 17 00:00:00 2001
From: metamuffin <metamuffin@disroot.org>
Date: Mon, 13 Jan 2025 15:23:50 +0100
Subject: filesystem resource cache

---
 shared/src/store.rs | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 59 insertions(+), 2 deletions(-)

(limited to 'shared/src/store.rs')

diff --git a/shared/src/store.rs b/shared/src/store.rs
index 673a40e..08e62be 100644
--- a/shared/src/store.rs
+++ b/shared/src/store.rs
@@ -16,21 +16,51 @@
 */
 use crate::{helper::ReadWrite, packets::Resource};
 use anyhow::Result;
+use log::info;
 use redb::{Database, TableDefinition};
-use std::{collections::HashMap, marker::PhantomData, path::Path, sync::Mutex};
+use std::{
+    collections::HashMap,
+    env::var,
+    fs::{File, create_dir_all, rename},
+    io::{Read, Write},
+    marker::PhantomData,
+    path::{Path, PathBuf},
+    sync::Mutex,
+};
 
 const T_ENTRIES: TableDefinition<[u8; 32], &[u8]> = TableDefinition::new("e");
 
 pub enum ResourceStore {
     Redb(Database),
+    Filesystem(PathBuf),
     Memory(Mutex<HashMap<Resource, Vec<u8>>>),
 }
 impl ResourceStore {
-    pub fn new_persistent(path: &Path) -> Result<Self> {
+    pub fn new_env() -> Result<Self> {
+        if var("WEARECHAT_RES_CACHE_USE_REDB").is_ok() {
+            ResourceStore::new_redb(
+                &xdg::BaseDirectories::with_prefix("wearechat")?
+                    .place_cache_file("resources.db")?,
+            )
+        } else {
+            ResourceStore::new_filesystem(
+                &xdg::BaseDirectories::with_prefix("wearechat")?
+                    .create_cache_directory("resources")?,
+            )
+        }
+    }
+    pub fn new_filesystem(path: &Path) -> Result<Self> {
+        info!("using filesystem resource cache in {path:?}");
+        create_dir_all(path)?;
+        Ok(Self::Filesystem(path.to_owned()))
+    }
+    pub fn new_redb(path: &Path) -> Result<Self> {
+        info!("initializing redb resource cache...");
         let db = Database::create(path)?;
         let txn = db.begin_write()?;
         txn.open_table(T_ENTRIES)?;
         txn.commit()?;
+        info!("done");
         Ok(Self::Redb(db))
     }
     pub fn new_memory() -> Self {
@@ -55,6 +85,16 @@ impl ResourceStore {
                 }
             }
             ResourceStore::Memory(map) => Ok(map.lock().unwrap().get(&key).map(|x| x.to_vec())),
+            ResourceStore::Filesystem(root) => {
+                let path = fs_cache_path(&root, key);
+                if path.exists() {
+                    let mut buf = Vec::new();
+                    File::open(path)?.read_to_end(&mut buf)?;
+                    Ok(Some(buf))
+                } else {
+                    Ok(None)
+                }
+            }
         }
     }
     pub fn set_raw(&self, value: &[u8]) -> Result<Resource> {
@@ -70,12 +110,19 @@ impl ResourceStore {
             ResourceStore::Memory(map) => {
                 map.lock().unwrap().insert(key, value.to_vec());
             }
+            ResourceStore::Filesystem(root) => {
+                let path = fs_cache_path(&root, key);
+                let path_temp = path.with_extension("part");
+                File::create(&path_temp)?.write_all(value)?;
+                rename(path_temp, path)?;
+            }
         }
         Ok(key)
     }
     pub fn iter(&self, mut cb: impl FnMut(&[u8])) -> Result<()> {
         match self {
             ResourceStore::Redb(_database) => todo!(),
+            ResourceStore::Filesystem(_root) => todo!(),
             ResourceStore::Memory(mutex) => {
                 mutex.lock().unwrap().values().for_each(|v| cb(v));
                 Ok(())
@@ -89,3 +136,13 @@ pub fn resource_hash(x: &[u8]) -> [u8; 32] {
     hasher.update(x);
     hasher.finalize().into()
 }
+
+fn fs_cache_path(path: &Path, res: Resource) -> PathBuf {
+    path.join(format!(
+        "{:08x}{:08x}{:08x}{:08x}",
+        u64::from_be_bytes(res.0[0..8].try_into().unwrap()),
+        u64::from_be_bytes(res.0[8..16].try_into().unwrap()),
+        u64::from_be_bytes(res.0[16..24].try_into().unwrap()),
+        u64::from_be_bytes(res.0[24..32].try_into().unwrap()),
+    ))
+}
-- 
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