1 files changed, 140 insertions, 0 deletions
diff --git a/autere_db/src/config.rs b/autere_db/src/config.rs
new file mode 100644
index 0000000..e8c6fa1
--- /dev/null
+++ b/autere_db/src/config.rs
@@ -0,0 +1,140 @@
+use super::*;
+
+pub struct ConfigBuilder {
+    data_dir: Option<String>,
+    segment_size: Option<usize>,
+    write_durability: Option<WriteDurability>,
+    read_consistency: Option<ReadConsistency>,
+
+    fields: Option<Vec<String>>,
+    primary_key: Option<String>,
+    secondary_keys: Option<Vec<String>>,
+}
+
+impl ConfigBuilder {
+    pub fn new() -> ConfigBuilder {
+        ConfigBuilder {
+            data_dir: None,
+            segment_size: None,
+            write_durability: None,
+            read_consistency: None,
+
+            fields: None,
+            primary_key: None,
+            secondary_keys: None,
+        }
+    }
+
+    /// The directory where the database will store its data.
+    pub fn data_dir(mut self, data_dir: impl Into<String>) -> Self {
+        self.data_dir = Some(data_dir.into());
+        self
+    }
+
+    /// The maximum size of a segment file in bytes.
+    /// Once a segment file reaches this size, it can be closed, rotated and compacted.
+    /// Note that this is not a hard limit: if `db.do_maintenance_tasks()` is not called,
+    /// the segment file may continue to grow.
+    pub fn segment_size(mut self, segment_size: usize) -> Self {
+        self.segment_size = Some(segment_size);
+        self
+    }
+
+    /// The write durability policy for the database.
+    /// This determines how writes are persisted to disk.
+    /// The default is WriteDurability::Flush.
+    pub fn write_durability(mut self, write_durability: WriteDurability) -> Self {
+        self.write_durability = Some(write_durability);
+        self
+    }
+
+    /// The read consistency policy for the database.
+    /// This determines how recent writes are visible when reading.
+    /// See individual `ReadConsistency` enum values for more information.
+    /// The default is ReadConsistency::Strong.
+    pub fn read_consistency(mut self, read_consistency: ReadConsistency) -> Self {
+        self.read_consistency = Some(read_consistency);
+        self
+    }
+
+    pub fn fields(mut self, schema: Vec<impl Into<String>>) -> Self {
+        self.fields = Some(schema.into_iter().map(|s| s.into()).collect());
+        self
+    }
+
+    pub fn primary_key(mut self, primary_key: impl Into<String>) -> Self {
+        self.primary_key = Some(primary_key.into());
+        self
+    }
+
+    pub fn secondary_keys(mut self, secondary_keys: Vec<impl Into<String>>) -> Self {
+        self.secondary_keys = Some(secondary_keys.into_iter().map(|s| s.into()).collect());
+        self
+    }
+
+    pub fn initialize(self) -> DBResult<DB> {
+        let schema = self
+            .fields
+            .ok_or_else(|| DBError::ValidationError("Schema not set".to_string()))?;
+        let primary_key = self
+            .primary_key
+            .ok_or_else(|| DBError::ValidationError("Primary key not set".to_string()))?;
+
+        let config = Config {
+            schema,
+            primary_key,
+            secondary_keys: self.secondary_keys.unwrap_or_default(),
+
+            data_dir: self.data_dir.clone().unwrap_or("db_data".to_string()),
+            segment_size: self.segment_size.unwrap_or(4 * 1024 * 1024), // 4MB
+            write_durability: self
+                .write_durability
+                .clone()
+                .unwrap_or(WriteDurability::Flush),
+            read_consistency: self
+                .read_consistency
+                .clone()
+                .unwrap_or(ReadConsistency::Strong),
+        };
+
+        DB::initialize(config)
+    }
+}
+
+#[derive(Clone)]
+pub struct Config {
+    pub schema: Vec<String>,
+    pub primary_key: String,
+    pub secondary_keys: Vec<String>,
+    pub data_dir: String,
+    pub segment_size: usize,
+    pub write_durability: WriteDurability,
+    pub read_consistency: ReadConsistency,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum ReadConsistency {
+    /// Reads by client A are guaranteed to see writes by themselves and any writes by other clients B
+    /// that were done before last index refresh. You must call `refresh_indexes()` manually to refresh indexes.
+    Eventual,
+    /// Reads by client A are guaranteed to see all writes. This is slower: all reads must first
+    /// refresh indexes.
+    Strong,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum WriteDurability {
+    /// Changes are written to the OS write buffer but not immediately synced to disk.
+    /// This is generally recommended. Most OSes will sync the write buffer to disk within a few seconds.
+    Flush,
+    /// Changes are written to the OS write buffer and synced to disk immediately.
+    /// Offers the best durability guarantees but is a lot slower.
+    FlushSync,
+}
+
+impl Display for WriteDurability {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
+        write!(f, "{:?}", self)?;
+        Ok(())
+    }
+}