Introduce ValueRc as an abstraction over Rc/Arc choice.

core/src/lib.rs

@@ -56,11 +56,13 @@ mod sql_types;
 
 pub use types::{
     Entid,
+    FromRc,
     KnownEntid,
     TypedValue,
     Binding,
     ValueType,
     ValueTypeTag,
+    ValueRc,
     now,
 };
 

core/src/types.rs

@@ -72,6 +72,11 @@ impl<T> FromRc<T> for Arc<T> where T: Sized + Clone {
     }
 }
 
+//
+// Use Rc for values.
+//
+pub type ValueRc<T> = Rc<T>;
+
 /// Represents one entid in the entid space.
 ///
 /// Per https://www.sqlite.org/datatype3.html (see also http://stackoverflow.com/a/8499544), SQLite
@@ -208,8 +213,8 @@ pub enum TypedValue {
     Double(OrderedFloat<f64>),
     Instant(DateTime<Utc>),               // Use `into()` to ensure truncation.
     // TODO: &str throughout?
-    String(Rc<String>),
+    String(ValueRc<String>),
-    Keyword(Rc<NamespacedKeyword>),
+    Keyword(ValueRc<NamespacedKeyword>),
     Uuid(Uuid),                        // It's only 128 bits, so this should be acceptable to clone.
 }
 
@@ -228,8 +233,8 @@ pub enum TypedValue {
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum Binding {
     Scalar(TypedValue),
-    Vec(Rc<Vec<Binding>>),
+    Vec(ValueRc<Vec<Binding>>),
-    Map(Rc<StructuredMap>),
+    Map(ValueRc<StructuredMap>),
 }
 
 impl<T> From<T> for Binding where T: Into<TypedValue> {
@@ -258,7 +263,7 @@ impl Binding {
 /// We entirely support the former, and partially support the latter -- you can alias
 /// using a different keyword only.
 #[derive(Debug, Eq, PartialEq)]
-pub struct StructuredMap(IndexMap<Rc<NamespacedKeyword>, Binding>);
+pub struct StructuredMap(IndexMap<ValueRc<NamespacedKeyword>, Binding>);
 
 impl Binding {
     /// Returns true if the provided type is `Some` and matches this value's type, or if the
@@ -311,14 +316,14 @@ impl TypedValue {
     }
 
     /// Construct a new `TypedValue::Keyword` instance by cloning the provided
-    /// values and wrapping them in a new `Rc`. This is expensive, so this might
+    /// values and wrapping them in a new `ValueRc`. This is expensive, so this might
     /// be best limited to tests.
     pub fn typed_ns_keyword(ns: &str, name: &str) -> TypedValue {
         NamespacedKeyword::new(ns, name).into()
     }
 
     /// Construct a new `TypedValue::String` instance by cloning the provided
-    /// value and wrapping it in a new `Rc`. This is expensive, so this might
+    /// value and wrapping it in a new `ValueRc`. This is expensive, so this might
     /// be best limited to tests.
     pub fn typed_string(s: &str) -> TypedValue {
         s.into()
@@ -381,31 +386,43 @@ impl From<Uuid> for TypedValue {
 
 impl<'a> From<&'a str> for TypedValue {
     fn from(value: &'a str) -> TypedValue {
-        TypedValue::String(Rc::new(value.to_string()))
+        TypedValue::String(ValueRc::new(value.to_string()))
+    }
+}
+
+impl From<Arc<String>> for TypedValue {
+    fn from(value: Arc<String>) -> TypedValue {
+        TypedValue::String(ValueRc::from_arc(value))
     }
 }
 
 impl From<Rc<String>> for TypedValue {
     fn from(value: Rc<String>) -> TypedValue {
-        TypedValue::String(value.clone())
+        TypedValue::String(ValueRc::from_rc(value))
     }
 }
 
 impl From<String> for TypedValue {
     fn from(value: String) -> TypedValue {
-        TypedValue::String(Rc::new(value))
+        TypedValue::String(ValueRc::new(value))
+    }
+}
+
+impl From<Arc<NamespacedKeyword>> for TypedValue {
+    fn from(value: Arc<NamespacedKeyword>) -> TypedValue {
+        TypedValue::Keyword(ValueRc::from_arc(value))
     }
 }
 
 impl From<Rc<NamespacedKeyword>> for TypedValue {
     fn from(value: Rc<NamespacedKeyword>) -> TypedValue {
-        TypedValue::Keyword(value.clone())
+        TypedValue::Keyword(ValueRc::from_rc(value))
     }
 }
 
 impl From<NamespacedKeyword> for TypedValue {
     fn from(value: NamespacedKeyword) -> TypedValue {
-        TypedValue::Keyword(Rc::new(value))
+        TypedValue::Keyword(ValueRc::new(value))
     }
 }
 
@@ -442,7 +459,7 @@ impl TypedValue {
         }
     }
 
-    pub fn into_kw(self) -> Option<Rc<NamespacedKeyword>> {
+    pub fn into_kw(self) -> Option<ValueRc<NamespacedKeyword>> {
         match self {
             TypedValue::Keyword(v) => Some(v),
             _ => None,
@@ -484,7 +501,7 @@ impl TypedValue {
         }
     }
 
-    pub fn into_string(self) -> Option<Rc<String>> {
+    pub fn into_string(self) -> Option<ValueRc<String>> {
         match self {
             TypedValue::String(v) => Some(v),
             _ => None,
@@ -521,7 +538,7 @@ impl Binding {
         }
     }
 
-    pub fn into_kw(self) -> Option<Rc<NamespacedKeyword>> {
+    pub fn into_kw(self) -> Option<ValueRc<NamespacedKeyword>> {
         match self {
             Binding::Scalar(TypedValue::Keyword(v)) => Some(v),
             _ => None,
@@ -563,7 +580,7 @@ impl Binding {
         }
     }
 
-    pub fn into_string(self) -> Option<Rc<String>> {
+    pub fn into_string(self) -> Option<ValueRc<String>> {
         match self {
             Binding::Scalar(TypedValue::String(v)) => Some(v),
             _ => None,

db/src/cache.rs

@@ -68,8 +68,6 @@ use std::iter::{
 
 use std::mem;
 
-use std::rc::Rc;
-
 use std::sync::Arc;
 
 use std::iter::Peekable;
@@ -85,6 +83,7 @@ use mentat_core::{
     Schema,
     TypedValue,
     UpdateableCache,
+    ValueRc,
 };
 
 use mentat_core::util::{
@@ -190,7 +189,7 @@ pub type Aev = (Entid, Entid, TypedValue);
 
 pub struct AevFactory {
     // Our own simple string-interning system.
-    strings: HashSet<Rc<String>>,
+    strings: HashSet<ValueRc<String>>,
 }
 
 impl AevFactory {

db/src/db.rs

@@ -19,7 +19,6 @@ use std::fmt::Display;
 use std::iter::{once, repeat};
 use std::ops::Range;
 use std::path::Path;
-use std::rc::Rc;
 
 use itertools;
 use itertools::Itertools;
@@ -51,7 +50,9 @@ use mentat_core::{
     TypedValue,
     ToMicros,
     ValueType,
+    ValueRc,
 };
+
 use errors::{ErrorKind, Result, ResultExt};
 use metadata;
 use schema::{
@@ -872,7 +873,7 @@ impl MentatStoring for rusqlite::Connection {
         let chunks: itertools::IntoChunks<_> = entities.into_iter().chunks(max_vars / bindings_per_statement);
 
         // From string to (searchid, value_type_tag).
-        let mut seen: HashMap<Rc<String>, (i64, i32)> = HashMap::with_capacity(entities.len());
+        let mut seen: HashMap<ValueRc<String>, (i64, i32)> = HashMap::with_capacity(entities.len());
 
         // We'd like to flat_map here, but it's not obvious how to flat_map across Result.
         let results: Result<Vec<()>> = chunks.into_iter().map(|chunk| -> Result<()> {

query-algebrizer/src/clauses/mod.rs

@@ -25,6 +25,10 @@ use std::fmt::{
     Formatter,
 };
 
+use std::ops::{
+    Deref,
+};
+
 use mentat_core::{
     Attribute,
     Entid,
@@ -97,13 +101,13 @@ pub use self::inputs::QueryInputs;
 use Known;
 
 // We do this a lot for errors.
-trait RcCloned<T> {
+trait Cloned<T> {
     fn cloned(&self) -> T;
 }
 
-impl<T: Clone> RcCloned<T> for ::std::rc::Rc<T> {
+impl<T: Clone> Cloned<T> for ::mentat_core::ValueRc<T> {
     fn cloned(&self) -> T {
-        self.as_ref().clone()
+        self.deref().clone()
     }
 }
 

query-algebrizer/src/clauses/pattern.rs

@@ -24,7 +24,7 @@ use mentat_query::{
     Variable,
 };
 
-use super::RcCloned;
+use super::Cloned;
 
 use clauses::{
     ConjoiningClauses,

query-algebrizer/src/types.rs

@@ -15,11 +15,10 @@ use std::fmt::{
     Result,
 };
 
-use std::rc::Rc;
-
 use mentat_core::{
     Entid,
     TypedValue,
+    ValueRc,
     ValueType,
     ValueTypeSet,
 };
@@ -709,7 +708,7 @@ pub enum EvolvedValuePlace {
     Entid(Entid),
     Value(TypedValue),
     EntidOrInteger(i64),
-    IdentOrKeyword(Rc<NamespacedKeyword>),
+    IdentOrKeyword(ValueRc<NamespacedKeyword>),
 }
 
 pub enum PlaceOrEmpty<T> {

query/src/lib.rs

@@ -55,7 +55,9 @@ pub use edn::{
 };
 
 use mentat_core::{
+    FromRc,
     TypedValue,
+    ValueRc,
     ValueType,
 };
 
@@ -205,7 +207,7 @@ pub enum NonIntegerConstant {
     Boolean(bool),
     BigInteger(BigInt),
     Float(OrderedFloat<f64>),
-    Text(Rc<String>),
+    Text(ValueRc<String>),
     Instant(DateTime<Utc>),
     Uuid(Uuid),
 }
@@ -225,13 +227,13 @@ impl NonIntegerConstant {
 
 impl<'a> From<&'a str> for NonIntegerConstant {
     fn from(val: &'a str) -> NonIntegerConstant {
-        NonIntegerConstant::Text(Rc::new(val.to_string()))
+        NonIntegerConstant::Text(ValueRc::new(val.to_string()))
     }
 }
 
 impl From<String> for NonIntegerConstant {
     fn from(val: String) -> NonIntegerConstant {
-        NonIntegerConstant::Text(Rc::new(val))
+        NonIntegerConstant::Text(ValueRc::new(val))
     }
 }
 
@@ -324,18 +326,18 @@ pub enum PatternNonValuePlace {
     Placeholder,
     Variable(Variable),
     Entid(i64),                       // Will always be +ve. See #190.
-    Ident(Rc<NamespacedKeyword>),
+    Ident(ValueRc<NamespacedKeyword>),
 }
 
 impl From<Rc<NamespacedKeyword>> for PatternNonValuePlace {
     fn from(value: Rc<NamespacedKeyword>) -> Self {
-        PatternNonValuePlace::Ident(value.clone())
+        PatternNonValuePlace::Ident(ValueRc::from_rc(value))
     }
 }
 
 impl From<NamespacedKeyword> for PatternNonValuePlace {
     fn from(value: NamespacedKeyword) -> Self {
-        PatternNonValuePlace::Ident(Rc::new(value))
+        PatternNonValuePlace::Ident(ValueRc::new(value))
     }
 }
 
@@ -387,7 +389,7 @@ impl FromValue<PatternNonValuePlace> for PatternNonValuePlace {
 
 #[derive(Clone, Debug, Eq, PartialEq)]
 pub enum IdentOrEntid {
-    Ident(Rc<NamespacedKeyword>),
+    Ident(NamespacedKeyword),
     Entid(i64),
 }
 
@@ -399,19 +401,19 @@ pub enum PatternValuePlace {
     Placeholder,
     Variable(Variable),
     EntidOrInteger(i64),
-    IdentOrKeyword(Rc<NamespacedKeyword>),
+    IdentOrKeyword(ValueRc<NamespacedKeyword>),
     Constant(NonIntegerConstant),
 }
 
 impl From<Rc<NamespacedKeyword>> for PatternValuePlace {
     fn from(value: Rc<NamespacedKeyword>) -> Self {
-        PatternValuePlace::IdentOrKeyword(value.clone())
+        PatternValuePlace::IdentOrKeyword(ValueRc::from_rc(value))
     }
 }
 
 impl From<NamespacedKeyword> for PatternValuePlace {
     fn from(value: NamespacedKeyword) -> Self {
-        PatternValuePlace::IdentOrKeyword(Rc::new(value))
+        PatternValuePlace::IdentOrKeyword(ValueRc::new(value))
     }
 }
 

sql/src/lib.rs

@@ -24,6 +24,7 @@ use ordered_float::OrderedFloat;
 use mentat_core::{
     ToMicros,
     TypedValue,
+    ValueRc,
 };
 
 pub use rusqlite::types::Value;
@@ -103,7 +104,7 @@ pub struct SQLiteQueryBuilder {
     // Instead we track byte and String arguments separately, mapping them to their argument name,
     // in order to dedupe. We'll add these to the regular argument vector later.
     byte_args: HashMap<Vec<u8>, String>,             // From value to argument name.
-    string_args: HashMap<Rc<String>, String>,        // From value to argument name.
+    string_args: HashMap<ValueRc<String>, String>,   // From value to argument name.
     args: Vec<(String, Rc<rusqlite::types::Value>)>, // (arg, value).
 }