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/server.rs | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)
 create mode 100644 src/server.rs

(limited to 'src/server.rs')

diff --git a/src/server.rs b/src/server.rs
new file mode 100644
index 0000000..72f848a
--- /dev/null
+++ b/src/server.rs
@@ -0,0 +1,139 @@
+pub mod attrs;
+pub mod blobref;
+mod index;
+mod object;
+mod storage;
+
+use self::{attrs::Attr, blobref::BlobRef, index::Index, object::Object, storage::Storage};
+use log::{error, warn};
+use serde::{Deserialize, Serialize};
+use std::{cmp, io::{Read, BufReader}, ops::Range, fs::File};
+
+#[derive(Debug)]
+pub enum Error {
+    Storage,
+    Index,
+}
+
+type Result<T> = std::result::Result<T, Error>;
+
+#[derive(Serialize, Deserialize)]
+pub struct Config {
+    storage: storage::Config,
+    index: index::Config,
+}
+
+pub struct Server {
+    storage: Storage,
+    index: Index,
+}
+
+pub struct Stream;
+
+impl Server {
+    pub fn new(config: &Config) -> Result<Self> {
+        let index = Index::new(&config.index).map_err(|_| Error::Index)?;
+        let storage = Storage::new(&config.storage);
+
+        Ok(Self { storage, index })
+    }
+
+    pub fn read(&self, blobref: &BlobRef, range: Range<usize>) -> Result<Vec<u8>> {
+        let object = self.index.get(blobref).map_err(|_| Error::Index)?;
+
+        let mut bytes: Vec<u8> = Vec::with_capacity(range.len());
+        let mut initial_chunk_offset = None;
+
+        for chunk in &object.chunks {
+            let chunk_end = chunk.offset + chunk.size;
+
+            if chunk_end < range.start {
+                continue;
+            }
+            if chunk.offset > range.end {
+                break;
+            }
+
+            if initial_chunk_offset.is_none() {
+                initial_chunk_offset = Some(chunk.offset);
+            }
+
+            let chunk_bytes = self
+                .storage
+                .get(&chunk.blobref)
+                .map_err(|_| Error::Storage)?;
+            bytes.extend_from_slice(&chunk_bytes);
+        }
+
+        let start = range.start - initial_chunk_offset.unwrap_or(0);
+        let end = cmp::min(start + range.len(), bytes.len());
+        Ok(bytes[start..end].to_vec())
+    }
+
+    pub fn copy(&self, data: &BufReader<File>) -> Result<BlobRef> {
+        // From fs: a. Write to temp file (via BufWriter?), then on flush
+        //          create a BufReader for temp file and pass it to this
+        //          method.
+        //          b. When writing to an existing file, first copy the data
+        //          in a temp file, then proceed with a.
+        Err(Error::Storage)
+    }
+
+    pub fn put<T: Read>(&self, data: T) -> Result<BlobRef> {
+        let (anchor, chunks) = self.storage.put(data).map_err(|e| {
+            error!("storage error: {e:?}");
+            Error::Storage
+        })?;
+
+        self.index
+            .put(&anchor, &chunks)
+            .map_err(|e| {
+                warn!("index error: {e:?}");
+            })
+            .ok();
+
+        Ok(anchor)
+    }
+
+    pub fn put_with_attrs<T: Read>(&mut self, data: T, attrs: &[Attr]) -> Result<BlobRef> {
+        let anchor = self.put(data)?;
+        self.set_attrs(&anchor, attrs)?;
+
+        Ok(anchor)
+    }
+
+    fn extend<T: Read>(&self, anchor: BlobRef, data: T) -> Result<BlobRef> {
+        self.storage
+            .extend(anchor, data)
+            .map_err(|e| {
+                error!("storage error: {e:?}");
+                Error::Storage
+            })
+            .map(|r| r.0)
+        // TODO self.index.extend
+    }
+
+    pub fn set_attrs(&mut self, anchor: &BlobRef, attrs: &[Attr]) -> Result<BlobRef> {
+        let patch = self.storage.set_attrs(anchor.clone(), attrs).map_err(|e| {
+            error!("storage error: {e:?}");
+            Error::Storage
+        })?;
+
+        self.index
+            .set_attrs(anchor, attrs)
+            .map_err(|e| {
+                warn!("index error: {e:?}");
+            })
+            .ok();
+
+        Ok(patch)
+    }
+
+    pub fn list(&self, range: Range<usize>, filter: Option<Attr>) -> Result<Vec<Object>> {
+        let limit = range.len();
+
+        self.index
+            .list(limit, range.start, filter)
+            .map_err(|_| Error::Index)
+    }
+}
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