Backup where I am

src/store.rs

@@ -1,89 +1,176 @@
-use std::{collections::{HashMap, HashSet}, path::Path, sync::Arc};
+use std::{
+    collections::{BTreeMap, HashMap, HashSet},
+    path::Path,
+    sync::Arc,
+};
 
 use anyhow::Result;
 use uuid::Uuid;
 
 use crate::models::{Document, Project};
 
-pub trait Filter = Fn(&Item) -> bool;
-pub trait Map<T> = Fn(&Item) -> T;
+pub trait Filter = Fn(&Row) -> bool;
+pub trait Map<T> = Fn(&Row) -> T;
 
-pub enum Item {
+pub enum Row {
     Project(Box<Project>),
     Document(Box<Document>),
+    //User(Box<User>),
 }
 
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
-pub struct ItemId(Uuid);
+pub struct RowId(Uuid);
 
+// supports comparison operators
 #[derive(Clone, Debug, Eq, Hash, PartialEq)]
 pub struct IndexId(String);
 
-pub type Index = HashSet<ItemId>;
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+pub struct IndexValue(String);
+
+pub enum Index {
+    BTree(BTreeMap<IndexValue, HashSet<RowId>>),
+    Unique(HashMap<IndexValue, RowId>),
+}
 
 pub struct Store {
-    items: HashMap<ItemId, Arc<Item>>,
+    rows: HashMap<RowId, Arc<Row>>,
     indexes: HashMap<IndexId, Index>,
 
     keyspace: fjall::Keyspace,
-    persistent_items: fjall::PartitionHandle,
+    data_partition: fjall::PartitionHandle,
+    permissions_partition: fjall::PartitionHandle,
 }
 
 impl Store {
     pub fn new<P: AsRef<Path>>(path: P) -> Result<Store> {
-        let items = HashMap::new();
+        let rows = HashMap::new();
         let indexes = HashMap::new();
 
         let kv_config = fjall::Config::new(path)
             .flush_workers(4)
             .compaction_workers(4);
         let keyspace = fjall::Keyspace::open(kv_config)?;
-        let persistent_items =
-            keyspace.open_partition("items", fjall::PartitionCreateOptions::default())?;
+        let data_partition =
+            keyspace.open_partition("data", fjall::PartitionCreateOptions::default())?;
+        let permissions_partition =
+            keyspace.open_partition("permissions", fjall::PartitionCreateOptions::default())?;
 
         Ok(Store {
-            items,
+            rows,
             indexes,
             keyspace,
-            persistent_items,
+            data_partition,
+            permissions_partition,
         })
     }
 
-    pub fn set(&mut self, _item: &Item) -> Result<()> {
+    pub fn set(&mut self, _item: &Row) -> Result<()> {
         todo!()
     }
 
     /// Retrieves an item from the store by id. This is always an in-memory
     /// operation and cannot fail.
-    pub fn get(&self, id: ItemId) -> Option<Arc<Item>> {
-        self.items.get(&id).cloned()
+    pub fn get(&self, id: RowId) -> Option<Arc<Row>> {
+        self.rows.get(&id).cloned()
+    }
 }
 
-    pub fn filter<F: Filter>(&self, _filter: F) -> Result<Vec<ItemId>> {
-        todo!()
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+pub struct Comparison {
+    index: IndexId,
+    value: IndexValue,
+    operator: ComparisonOperator,
 }
 
-    pub fn map<T, M: Map<T>>(&self, _transform: M) -> Result<Vec<T>> {
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+pub enum ComparisonOperator {
+    Eq,
+    Gt,
+    Gte,
+    Lt,
+    Lte,
+}
+
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+pub enum QueryOperation {
+    All,
+    Where(Comparison),
+    Limit(usize),
+    Offset(usize),
+    OrderBy(IndexId),
+}
+
+/// Describes a set of operations to query for data in the database. To read the
+/// data, this gets transformed into a QuerySet, which contains the results.
+pub struct Query {
+    operations: Vec<QueryOperation>,
+}
+
+impl Query {
+    pub fn new() -> Query {
+        Query {
+            operations: Vec::new(),
+        }
+    }
+
+    pub fn all(&mut self) -> &mut Self {
+        self.operations.push(QueryOperation::All);
+        self
+    }
+
+    /// Filters down the set of rows via comparison operators
+    pub fn restrict(
+        &mut self,
+        index: IndexId,
+        value: IndexValue,
+        operator: ComparisonOperator,
+    ) -> &mut Self {
+        self.operations.push(QueryOperation::Where(Comparison {
+            index,
+            value,
+            operator,
+        }));
+        self
+    }
+
+    pub fn limit(&mut self, limit: usize) -> &mut Self {
+        self.operations.push(QueryOperation::Limit(limit));
+        self
+    }
+
+    pub fn offset(&mut self, offset: usize) -> &mut Self {
+        self.operations.push(QueryOperation::Offset(offset));
+        self
+    }
+
+    pub fn order_by(&mut self, index: IndexId) -> &mut Self {
+        self.operations.push(QueryOperation::OrderBy(index));
+        self
+    }
+
+    pub fn execute(&self) -> QuerySet {
         todo!()
     }
 }
 
-// TODO: can filter and map be done in terms of an iterator?
-// like, the real Rust iterator trait?
+/// The results of a Query, this will contain the concrete Rows which have been
+/// retrieved.
+pub struct QuerySet {}
 
-
-pub struct QuerySet {
-    indexes: Vec<Index>, // TODO: but use a ref, once this is figured out
-
-}
-
-impl QuerySet {
-}
+impl QuerySet {}
 
 impl Iterator for QuerySet {
-    type Item = Item;
+    type Item = Row;
 
     fn next(&mut self) -> Option<Self::Item> {
         todo!()
     }
 }
+
+// How I'd like to do queries:
+//
+// store.query().via(OnlyProjects).
+//
+//
+//