start implementing a skeleton of the v1 dump reader

dump/src/reader/mod.rs

@@ -0,0 +1,105 @@
+use std::path::Path;
+use std::{fs::File, io::BufReader};
+
+use flate2::{bufread::GzDecoder, Compression};
+use index::{Settings, Unchecked};
+use index_scheduler::TaskView;
+use meilisearch_auth::Key;
+use serde::{Deserialize, Serialize};
+
+use tempfile::TempDir;
+use time::OffsetDateTime;
+
+use crate::{Result, Version};
+
+// use self::loaders::{v2, v3, v4, v5};
+
+// pub mod error;
+// mod compat;
+// mod loaders;
+mod v1;
+// mod v6;
+
+pub fn open(
+    dump_path: &Path,
+) -> Result<
+    impl DumpReader<
+        Document = serde_json::Value,
+        Settings = Settings<Unchecked>,
+        Task = TaskView,
+        UpdateFile = (),
+        Key = Key,
+    >,
+> {
+    let path = TempDir::new()?;
+
+    let dump = File::open(dump_path)?;
+    let mut dump = BufReader::new(dump);
+
+    let gz = GzDecoder::new(&mut dump);
+    let mut archive = tar::Archive::new(gz);
+    archive.unpack(path.path())?;
+
+    #[derive(Deserialize)]
+    struct MetadataVersion {
+        pub dump_version: Version,
+    }
+    let mut meta_file = File::open(path.path().join("metadata.json"))?;
+    let MetadataVersion { dump_version } = serde_json::from_reader(&mut meta_file)?;
+
+    match dump_version {
+        // Version::V1 => Ok(Box::new(v1::Reader::open(path)?)),
+        Version::V1 => todo!(),
+        Version::V2 => todo!(),
+        Version::V3 => todo!(),
+        Version::V4 => todo!(),
+        Version::V5 => todo!(),
+        Version::V6 => todo!(),
+    };
+
+    todo!()
+}
+
+pub trait DumpReader {
+    type Document;
+    type Settings;
+
+    type Task;
+    type UpdateFile;
+
+    type Key;
+
+    /// Return the version of the dump.
+    fn version(&self) -> Version;
+
+    /// Return at which date the index was created.
+    fn date(&self) -> Result<Option<OffsetDateTime>>;
+
+    /// Return an iterator over each indexes.
+    fn indexes(
+        &self,
+    ) -> Result<
+        Box<
+            dyn Iterator<
+                Item = Box<dyn IndexReader<Document = Self::Document, Settings = Self::Settings>>,
+            >,
+        >,
+    >;
+
+    /// Return all the tasks in the dump with a possible update file.
+    fn tasks(
+        &self,
+    ) -> Result<Box<dyn Iterator<Item = Result<(Self::Task, Option<Self::UpdateFile>)>>>>;
+
+    /// Return all the keys.
+    fn keys(&self) -> Result<Box<dyn Iterator<Item = Self::Key>>>;
+}
+
+pub trait IndexReader {
+    type Document;
+    type Settings;
+
+    fn name(&self) -> &str;
+    fn documents(&self) -> Result<Box<dyn Iterator<Item = Self::Document>>>;
+    fn settings(&self) -> Result<Self::Settings>;
+}