auto merge of #7885 : graydon/rust/workcache-fixes-1, r=pcwalton

This just redoes various parts of workcache to support context-cloning (eventually quite crudely, via ARCs), the absence of which was blocking rustpkg from being able to use it. Better versions of this are possible (notably removing the ARCs on everything except the database) but it ought to work well enough for now.

src/libextra/json.rs

@@ -41,7 +41,7 @@ pub enum Json {
 }
 
 pub type List = ~[Json];
-pub type Object = HashMap<~str, Json>;
+pub type Object = TreeMap<~str, Json>;
 
 #[deriving(Eq)]
 /// If an error occurs while parsing some JSON, this is the structure which is
@@ -809,7 +809,7 @@ impl<T : iterator::Iterator<char>> Parser<T> {
         self.bump();
         self.parse_whitespace();
 
-        let mut values = ~HashMap::new();
+        let mut values = ~TreeMap::new();
 
         if self.ch == '}' {
           self.bump();
@@ -1087,7 +1087,7 @@ impl serialize::Decoder for Decoder {
         let len = match self.stack.pop() {
             Object(obj) => {
                 let len = obj.len();
-                for obj.consume().advance |(key, value)| {
+                for obj.consume_iter().advance |(key, value)| {
                     self.stack.push(value);
                     self.stack.push(String(key));
                 }
@@ -1294,19 +1294,19 @@ impl<A:ToJson> ToJson for ~[A] {
     fn to_json(&self) -> Json { List(self.map(|elt| elt.to_json())) }
 }
 
-impl<A:ToJson> ToJson for HashMap<~str, A> {
+impl<A:ToJson> ToJson for TreeMap<~str, A> {
     fn to_json(&self) -> Json {
-        let mut d = HashMap::new();
+        let mut d = TreeMap::new();
         for self.iter().advance |(key, value)| {
             d.insert((*key).clone(), value.to_json());
         }
         Object(~d)
     }
 }
 
-impl<A:ToJson> ToJson for TreeMap<~str, A> {
+impl<A:ToJson> ToJson for HashMap<~str, A> {
     fn to_json(&self) -> Json {
-        let mut d = HashMap::new();
+        let mut d = TreeMap::new();
         for self.iter().advance |(key, value)| {
             d.insert((*key).clone(), value.to_json());
         }
@@ -1338,11 +1338,11 @@ mod tests {
 
     use super::*;
 
-    use std::hashmap::HashMap;
     use std::io;
     use std::result;
 
-    use extra::serialize::Decodable;
+    use serialize::Decodable;
+    use treemap::TreeMap;
 
     #[deriving(Eq, Encodable, Decodable)]
     enum Animal {
@@ -1363,7 +1363,7 @@ mod tests {
     }
 
     fn mk_object(items: &[(~str, Json)]) -> Json {
-        let mut d = ~HashMap::new();
+        let mut d = ~TreeMap::new();
 
         for items.iter().advance |item| {
             match *item {
@@ -1954,7 +1954,7 @@ mod tests {
     fn test_decode_map() {
         let s = ~"{\"a\": \"Dog\", \"b\": [\"Frog\", \"Henry\", 349]}";
         let mut decoder = Decoder(from_str(s).unwrap());
-        let mut map: HashMap<~str, Animal> = Decodable::decode(&mut decoder);
+        let mut map: TreeMap<~str, Animal> = Decodable::decode(&mut decoder);
 
         assert_eq!(map.pop(&~"a"), Some(Dog));
         assert_eq!(map.pop(&~"b"), Some(Frog(~"Henry", 349)));

src/libextra/test.rs

@@ -38,7 +38,6 @@ use std::task;
 use std::to_str::ToStr;
 use std::u64;
 use std::f64;
-use std::hashmap::HashMap;
 use std::os;
 
 
@@ -852,7 +851,7 @@ fn calc_result(desc: &TestDesc, task_succeeded: bool) -> TestResult {
 
 impl ToJson for Metric {
     fn to_json(&self) -> json::Json {
-        let mut map = ~HashMap::new();
+        let mut map = ~TreeMap::new();
         map.insert(~"value", json::Number(self.value as float));
         map.insert(~"noise", json::Number(self.noise as float));
         json::Object(map)

src/libextra/treemap.rs

@@ -204,6 +204,19 @@ impl<K: TotalOrd, V> TreeMap<K, V> {
     pub fn iter<'a>(&'a self) -> TreeMapIterator<'a, K, V> {
         TreeMapIterator{stack: ~[], node: &self.root, remaining: self.length}
     }
+
+    /// Get a lazy iterator that consumes the treemap.
+    pub fn consume_iter(self) -> TreeMapConsumeIterator<K, V> {
+        let TreeMap { root: root, length: length } = self;
+        let stk = match root {
+            None => ~[],
+            Some(~tn) => ~[tn]
+        };
+        TreeMapConsumeIterator {
+            stack: stk,
+            remaining: length
+        }
+    }
 }
 
 /// Lazy forward iterator over a map
@@ -241,6 +254,56 @@ impl<'self, K, V> Iterator<(&'self K, &'self V)> for TreeMapIterator<'self, K, V
     }
 }
 
+/// Lazy forward iterator over a map that consumes the map while iterating
+pub struct TreeMapConsumeIterator<K, V> {
+    priv stack: ~[TreeNode<K, V>],
+    priv remaining: uint
+}
+
+impl<K, V> Iterator<(K, V)> for TreeMapConsumeIterator<K,V> {
+    #[inline]
+    fn next(&mut self) -> Option<(K, V)> {
+        while !self.stack.is_empty() {
+            let TreeNode {
+                key: key,
+                value: value,
+                left: left,
+                right: right,
+                level: level
+            } = self.stack.pop();
+
+            match left {
+                Some(~left) => {
+                    let n = TreeNode {
+                        key: key,
+                        value: value,
+                        left: None,
+                        right: right,
+                        level: level
+                    };
+                    self.stack.push(n);
+                    self.stack.push(left);
+                }
+                None => {
+                    match right {
+                        Some(~right) => self.stack.push(right),
+                        None => ()
+                    }
+                    self.remaining -= 1;
+                    return Some((key, value))
+                }
+            }
+        }
+        None
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (uint, Option<uint>) {
+        (self.remaining, Some(self.remaining))
+    }
+
+}
+
 impl<'self, T> Iterator<&'self T> for TreeSetIterator<'self, T> {
     /// Advance the iterator to the next node (in order). If there are no more nodes, return `None`.
     #[inline]