feat: Move the Schema to its own workspace crate

meilidb-schema/src/lib.rs

@@ -0,0 +1,315 @@
+use std::collections::{HashMap, BTreeMap};
+use std::io::{Read, Write};
+use std::error::Error;
+use std::{fmt, u16};
+use std::ops::BitOr;
+use std::sync::Arc;
+
+use serde::{Serialize, Deserialize};
+use linked_hash_map::LinkedHashMap;
+
+pub const STORED: SchemaProps  = SchemaProps { stored: true,  indexed: false, ranked: false };
+pub const INDEXED: SchemaProps = SchemaProps { stored: false, indexed: true,  ranked: false };
+pub const RANKED: SchemaProps  = SchemaProps { stored: false, indexed: false, ranked: true  };
+
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct SchemaProps {
+    #[serde(default)]
+    stored: bool,
+
+    #[serde(default)]
+    indexed: bool,
+
+    #[serde(default)]
+    ranked: bool,
+}
+
+impl SchemaProps {
+    pub fn is_stored(self) -> bool {
+        self.stored
+    }
+
+    pub fn is_indexed(self) -> bool {
+        self.indexed
+    }
+
+    pub fn is_ranked(self) -> bool {
+        self.ranked
+    }
+}
+
+impl BitOr for SchemaProps {
+    type Output = Self;
+
+    fn bitor(self, other: Self) -> Self::Output {
+        SchemaProps {
+            stored: self.stored | other.stored,
+            indexed: self.indexed | other.indexed,
+            ranked: self.ranked | other.ranked,
+        }
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+pub struct SchemaBuilder {
+    identifier: String,
+    attributes: LinkedHashMap<String, SchemaProps>,
+}
+
+impl SchemaBuilder {
+    pub fn with_identifier<S: Into<String>>(name: S) -> SchemaBuilder {
+        SchemaBuilder {
+            identifier: name.into(),
+            attributes: LinkedHashMap::new(),
+        }
+    }
+
+    pub fn new_attribute<S: Into<String>>(&mut self, name: S, props: SchemaProps) -> SchemaAttr {
+        let len = self.attributes.len();
+        if self.attributes.insert(name.into(), props).is_some() {
+            panic!("Field already inserted.")
+        }
+        SchemaAttr(len as u16)
+    }
+
+    pub fn build(self) -> Schema {
+        let mut attrs = HashMap::new();
+        let mut props = Vec::new();
+
+        for (i, (name, prop)) in self.attributes.into_iter().enumerate() {
+            attrs.insert(name.clone(), SchemaAttr(i as u16));
+            props.push((name, prop));
+        }
+
+        let identifier = self.identifier;
+        Schema { inner: Arc::new(InnerSchema { identifier, attrs, props }) }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Schema {
+    inner: Arc<InnerSchema>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct InnerSchema {
+    identifier: String,
+    attrs: HashMap<String, SchemaAttr>,
+    props: Vec<(String, SchemaProps)>,
+}
+
+impl Schema {
+    pub fn from_toml<R: Read>(mut reader: R) -> Result<Schema, Box<Error>> {
+        let mut buffer = Vec::new();
+        reader.read_to_end(&mut buffer)?;
+        let builder: SchemaBuilder = toml::from_slice(&buffer)?;
+        Ok(builder.build())
+    }
+
+    pub fn to_toml<W: Write>(&self, mut writer: W) -> Result<(), Box<Error>> {
+        let identifier = self.inner.identifier.clone();
+        let attributes = self.attributes_ordered();
+        let builder = SchemaBuilder { identifier, attributes };
+
+        let string = toml::to_string_pretty(&builder)?;
+        writer.write_all(string.as_bytes())?;
+
+        Ok(())
+    }
+
+    pub fn from_json<R: Read>(mut reader: R) -> Result<Schema, Box<Error>> {
+        let mut buffer = Vec::new();
+        reader.read_to_end(&mut buffer)?;
+        let builder: SchemaBuilder = serde_json::from_slice(&buffer)?;
+        Ok(builder.build())
+    }
+
+    pub fn to_json<W: Write>(&self, mut writer: W) -> Result<(), Box<Error>> {
+        let identifier = self.inner.identifier.clone();
+        let attributes = self.attributes_ordered();
+        let builder = SchemaBuilder { identifier, attributes };
+        let string = serde_json::to_string_pretty(&builder)?;
+        writer.write_all(string.as_bytes())?;
+
+        Ok(())
+    }
+
+    pub fn read_from_bin<R: Read>(reader: R) -> bincode::Result<Schema> {
+        let builder: SchemaBuilder = bincode::deserialize_from(reader)?;
+        Ok(builder.build())
+    }
+
+    pub fn write_to_bin<W: Write>(&self, writer: W) -> bincode::Result<()> {
+        let identifier = self.inner.identifier.clone();
+        let attributes = self.attributes_ordered();
+        let builder = SchemaBuilder { identifier, attributes };
+
+        bincode::serialize_into(writer, &builder)
+    }
+
+    fn attributes_ordered(&self) -> LinkedHashMap<String, SchemaProps> {
+        let mut ordered = BTreeMap::new();
+        for (name, attr) in &self.inner.attrs {
+            let (_, props) = self.inner.props[attr.0 as usize];
+            ordered.insert(attr.0, (name, props));
+        }
+
+        let mut attributes = LinkedHashMap::with_capacity(ordered.len());
+        for (_, (name, props)) in ordered {
+            attributes.insert(name.clone(), props);
+        }
+
+        attributes
+    }
+
+    pub fn props(&self, attr: SchemaAttr) -> SchemaProps {
+        let (_, props) = self.inner.props[attr.0 as usize];
+        props
+    }
+
+    pub fn identifier_name(&self) -> &str {
+        &self.inner.identifier
+    }
+
+    pub fn attribute<S: AsRef<str>>(&self, name: S) -> Option<SchemaAttr> {
+        self.inner.attrs.get(name.as_ref()).cloned()
+    }
+
+    pub fn attribute_name(&self, attr: SchemaAttr) -> &str {
+        let (name, _) = &self.inner.props[attr.0 as usize];
+        name
+    }
+
+    pub fn iter<'a>(&'a self) -> impl Iterator<Item=(&str, SchemaAttr, SchemaProps)> + 'a {
+        self.inner.props.iter()
+            .map(move |(name, prop)| {
+                let attr = self.inner.attrs.get(name).unwrap();
+                (name.as_str(), *attr, *prop)
+            })
+    }
+}
+
+#[derive(Serialize, Deserialize)]
+#[derive(Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Hash)]
+pub struct SchemaAttr(pub u16);
+
+impl SchemaAttr {
+    pub const fn new(value: u16) -> SchemaAttr {
+        SchemaAttr(value)
+    }
+
+    pub const fn min() -> SchemaAttr {
+        SchemaAttr(u16::min_value())
+    }
+
+    pub const fn max() -> SchemaAttr {
+        SchemaAttr(u16::max_value())
+    }
+
+    pub fn next(self) -> Option<SchemaAttr> {
+        self.0.checked_add(1).map(SchemaAttr)
+    }
+
+    pub fn prev(self) -> Option<SchemaAttr> {
+        self.0.checked_sub(1).map(SchemaAttr)
+    }
+}
+
+impl fmt::Display for SchemaAttr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::error::Error;
+
+    #[test]
+    fn serialize_deserialize() -> bincode::Result<()> {
+        let mut builder = SchemaBuilder::with_identifier("id");
+        builder.new_attribute("alpha", STORED);
+        builder.new_attribute("beta", STORED | INDEXED);
+        builder.new_attribute("gamma", INDEXED);
+        let schema = builder.build();
+
+        let mut buffer = Vec::new();
+
+        schema.write_to_bin(&mut buffer)?;
+        let schema2 = Schema::read_from_bin(buffer.as_slice())?;
+
+        assert_eq!(schema, schema2);
+
+        Ok(())
+    }
+
+    #[test]
+    fn serialize_deserialize_toml() -> Result<(), Box<Error>> {
+        let mut builder = SchemaBuilder::with_identifier("id");
+        builder.new_attribute("alpha", STORED);
+        builder.new_attribute("beta", STORED | INDEXED);
+        builder.new_attribute("gamma", INDEXED);
+        let schema = builder.build();
+
+        let mut buffer = Vec::new();
+        schema.to_toml(&mut buffer)?;
+
+        let schema2 = Schema::from_toml(buffer.as_slice())?;
+        assert_eq!(schema, schema2);
+
+        let data = r#"
+            identifier = "id"
+
+            [attributes."alpha"]
+            stored = true
+
+            [attributes."beta"]
+            stored = true
+            indexed = true
+
+            [attributes."gamma"]
+            indexed = true
+        "#;
+        let schema2 = Schema::from_toml(data.as_bytes())?;
+        assert_eq!(schema, schema2);
+
+        Ok(())
+    }
+
+    #[test]
+    fn serialize_deserialize_json() -> Result<(), Box<Error>> {
+        let mut builder = SchemaBuilder::with_identifier("id");
+        builder.new_attribute("alpha", STORED);
+        builder.new_attribute("beta", STORED | INDEXED);
+        builder.new_attribute("gamma", INDEXED);
+        let schema = builder.build();
+
+        let mut buffer = Vec::new();
+        schema.to_json(&mut buffer)?;
+
+        let schema2 = Schema::from_json(buffer.as_slice())?;
+        assert_eq!(schema, schema2);
+
+        let data = r#"
+            {
+                "identifier": "id",
+                "attributes": {
+                    "alpha": {
+                        "stored": true
+                    },
+                    "beta": {
+                        "stored": true,
+                        "indexed": true
+                    },
+                    "gamma": {
+                        "indexed": true
+                    }
+                }
+            }"#;
+        let schema2 = Schema::from_json(data.as_bytes())?;
+        assert_eq!(schema, schema2);
+
+        Ok(())
+    }
+}