Support :db/noHistory for attributes. (#622) r=nalexander

At this point we never discard history, but this completes the API support for doing so.

core/src/lib.rs

@@ -700,6 +700,9 @@ pub struct Attribute {
     /// They are used to compose entities from component sub-entities: they are fetched recursively
     /// by pull expressions, and they are automatically recursively deleted where appropriate.
     pub component: bool,
+
+    /// `true` if this attribute doesn't require history to be kept, i.e., it is `:db/noHistory true`.
+    pub no_history: bool,
 }
 
 impl Attribute {
@@ -750,6 +753,10 @@ impl Attribute {
             attribute_map.insert(values::DB_IS_COMPONENT.clone(), edn::Value::Boolean(true));
         }
 
+        if self.no_history {
+            attribute_map.insert(values::DB_NO_HISTORY.clone(), edn::Value::Boolean(true));
+        }
+
         edn::Value::Map(attribute_map)
     }
 }
@@ -764,6 +771,7 @@ impl Default for Attribute {
             multival: false,
             unique: None,
             component: false,
+            no_history: false,
         }
     }
 }
@@ -894,6 +902,7 @@ mod test {
             unique: None,
             multival: false,
             component: false,
+            no_history: false,
         };
 
         assert!(attr1.flags() & AttributeBitFlags::IndexAVET as u8 != 0);
@@ -908,6 +917,7 @@ mod test {
             unique: Some(attribute::Unique::Value),
             multival: false,
             component: false,
+            no_history: false,
         };
 
         assert!(attr2.flags() & AttributeBitFlags::IndexAVET as u8 == 0);
@@ -922,6 +932,7 @@ mod test {
             unique: Some(attribute::Unique::Identity),
             multival: false,
             component: false,
+            no_history: false,
         };
 
         assert!(attr3.flags() & AttributeBitFlags::IndexAVET as u8 == 0);
@@ -954,6 +965,7 @@ mod test {
             unique: None,
             multival: false,
             component: false,
+            no_history: true,
         };
         associate_ident(&mut schema, NamespacedKeyword::new("foo", "bar"), 97);
         add_attribute(&mut schema, 97, attr1);
@@ -965,6 +977,7 @@ mod test {
             unique: Some(attribute::Unique::Value),
             multival: true,
             component: false,
+            no_history: false,
         };
         associate_ident(&mut schema, NamespacedKeyword::new("foo", "bas"), 98);
         add_attribute(&mut schema, 98, attr2);
@@ -976,6 +989,7 @@ mod test {
             unique: Some(attribute::Unique::Identity),
             multival: false,
             component: true,
+            no_history: false,
         };
 
         associate_ident(&mut schema, NamespacedKeyword::new("foo", "bat"), 99);
@@ -986,7 +1000,8 @@ mod test {
         let expected_output = r#"[ {   :db/ident     :foo/bar
     :db/valueType :db.type/ref
     :db/cardinality :db.cardinality/one
-    :db/index true },
+    :db/index true
+    :db/noHistory true },
 {   :db/ident     :foo/bas
     :db/valueType :db.type/string
     :db/cardinality :db.cardinality/many

core/src/values.rs

@@ -47,6 +47,7 @@ lazy_static_namespaced_keyword_value!(DB_IDENT, "db", "ident");
 lazy_static_namespaced_keyword_value!(DB_INDEX, "db", "index");
 lazy_static_namespaced_keyword_value!(DB_INSTALL_ATTRIBUTE, "db.install", "attribute");
 lazy_static_namespaced_keyword_value!(DB_IS_COMPONENT, "db", "component");
+lazy_static_namespaced_keyword_value!(DB_NO_HISTORY, "db", "noHistory");
 lazy_static_namespaced_keyword_value!(DB_PART_DB, "db.part", "db");
 lazy_static_namespaced_keyword_value!(DB_RETRACT, "db", "retract");
 lazy_static_namespaced_keyword_value!(DB_TYPE_BOOLEAN, "db.type", "boolean");

db/src/metadata.rs

@@ -171,6 +171,13 @@ pub fn update_attribute_map_from_entid_triples<U>(attribute_map: &mut AttributeM
                 }
             },
 
+            entids::DB_NO_HISTORY => {
+                match *value {
+                    TypedValue::Boolean(x) => { builder.no_history(x); },
+                    _ => bail!(ErrorKind::BadSchemaAssertion(format!("Expected [... :db/noHistory true|false] but got [... :db/noHistory {:?}]", value)))
+                }
+            },
+
             _ => {
                 bail!(ErrorKind::BadSchemaAssertion(format!("Do not recognize attribute {} for entid {}", attr, entid)))
             }

db/src/schema.rs

@@ -79,6 +79,7 @@ pub struct AttributeBuilder {
     index: Option<bool>,
     fulltext: Option<bool>,
     component: Option<bool>,
+    no_history: Option<bool>,
 }
 
 impl AttributeBuilder {
@@ -127,6 +128,11 @@ impl AttributeBuilder {
         self
     }
 
+    pub fn no_history<'a>(&'a mut self, no_history: bool) -> &'a mut Self {
+        self.no_history = Some(no_history);
+        self
+    }
+
     pub fn validate_install_attribute(&self) -> Result<()> {
         if self.value_type.is_none() {
             bail!(ErrorKind::BadSchemaAssertion("Schema attribute for new attribute does not set :db/valueType".into()));
@@ -164,6 +170,9 @@ impl AttributeBuilder {
         if let Some(component) = self.component {
             attribute.component = component;
         }
+        if let Some(no_history) = self.no_history {
+            attribute.no_history = no_history;
+        }
 
         attribute
     }
@@ -194,6 +203,12 @@ impl AttributeBuilder {
                 mutations.push(AttributeAlteration::IsComponent);
             }
         }
+        if let Some(no_history) = self.no_history {
+            if no_history != attribute.no_history {
+                attribute.no_history = no_history;
+                mutations.push(AttributeAlteration::NoHistory);
+            }
+        }
 
         mutations
     }
@@ -326,6 +341,7 @@ mod test {
             unique: None,
             multival: false,
             component: false,
+            no_history: false,
         });
         // attribute is unique by value and an index
         add_attribute(&mut schema, NamespacedKeyword::new("foo", "baz"), 98, Attribute {
@@ -335,6 +351,7 @@ mod test {
             unique: Some(attribute::Unique::Value),
             multival: false,
             component: false,
+            no_history: false,
         });
         // attribue is unique by identity and an index
         add_attribute(&mut schema, NamespacedKeyword::new("foo", "bat"), 99, Attribute {
@@ -344,6 +361,7 @@ mod test {
             unique: Some(attribute::Unique::Identity),
             multival: false,
             component: false,
+            no_history: false,
         });
         // attribute is a components and a `Ref`
         add_attribute(&mut schema, NamespacedKeyword::new("foo", "bak"), 100, Attribute {
@@ -353,6 +371,7 @@ mod test {
             unique: None,
             multival: false,
             component: true,
+            no_history: false,
         });
         // fulltext attribute is a string and an index
         add_attribute(&mut schema, NamespacedKeyword::new("foo", "bap"), 101, Attribute {
@@ -362,6 +381,7 @@ mod test {
             unique: None,
             multival: false,
             component: false,
+            no_history: false,
         });
 
         assert!(validate_attribute_map(&schema.entid_map, &schema.attribute_map).is_ok());
@@ -379,6 +399,7 @@ mod test {
             unique: Some(attribute::Unique::Value),
             multival: false,
             component: false,
+            no_history: false,
         });
 
         let err = validate_attribute_map(&schema.entid_map, &schema.attribute_map).err();
@@ -401,6 +422,7 @@ mod test {
             unique: Some(attribute::Unique::Identity),
             multival: false,
             component: false,
+            no_history: false,
         });
 
         let err = validate_attribute_map(&schema.entid_map, &schema.attribute_map).err();
@@ -423,6 +445,7 @@ mod test {
             unique: None,
             multival: false,
             component: true,
+            no_history: false,
         });
 
         let err = validate_attribute_map(&schema.entid_map, &schema.attribute_map).err();
@@ -445,6 +468,7 @@ mod test {
             unique: None,
             multival: false,
             component: false,
+            no_history: false,
         });
 
         let err = validate_attribute_map(&schema.entid_map, &schema.attribute_map).err();
@@ -466,6 +490,7 @@ mod test {
             unique: None,
             multival: false,
             component: false,
+            no_history: false,
         });
 
         let err = validate_attribute_map(&schema.entid_map, &schema.attribute_map).err();

src/vocabulary.rs

@@ -207,10 +207,9 @@ lazy_static! {
         kw!(:db.cardinality/many)
     };
 
-    // Not yet supported.
+    static ref DB_NO_HISTORY: NamespacedKeyword = {
-    // static ref DB_NO_HISTORY: NamespacedKeyword = {
+        NamespacedKeyword::new("db", "noHistory")
-    //     NamespacedKeyword::new("db", "noHistory")
+    };
-    // };
 }
 
 trait HasCoreSchema {
@@ -260,8 +259,7 @@ impl Definition {
         let a_value_type = via.core_attribute(&DB_VALUE_TYPE)?;
         let a_unique = via.core_attribute(&DB_UNIQUE)?;
 
-        // Not yet supported.
+        let a_no_history = via.core_attribute(&DB_NO_HISTORY)?;
-        // let a_no_history = via.core_attribute(&DB_NO_HISTORY)?;
 
         let v_cardinality_many = via.core_entid(&DB_CARDINALITY_MANY)?;
         let v_cardinality_one = via.core_entid(&DB_CARDINALITY_ONE)?;
@@ -310,6 +308,9 @@ impl Definition {
             if attr.component {
                 builder.add(tempid.clone(), a_is_component, TypedValue::Boolean(true))?;
             }
+            if attr.no_history {
+                builder.add(tempid.clone(), a_no_history, TypedValue::Boolean(true))?;
+            }
 
             if let Some(u) = attr.unique {
                 let uu = match u {