From 470d5692febd332803a31c02730de02389b992ce Mon Sep 17 00:00:00 2001
From: WangRunji <wangrunji0408@163.com>
Date: Thu, 19 Apr 2018 15:28:32 +0800
Subject: [PATCH] Pass test for FifoSwapManager. Change interface.

---
 crate/memory/src/swap/fifo.rs            | 15 +++++++------
 crate/memory/src/swap/mock_page_table.rs | 28 ++++++++++++++++--------
 crate/memory/src/swap/mod.rs             |  4 ++--
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/crate/memory/src/swap/fifo.rs b/crate/memory/src/swap/fifo.rs
index 8a91f52..4a006ee 100644
--- a/crate/memory/src/swap/fifo.rs
+++ b/crate/memory/src/swap/fifo.rs
@@ -22,14 +22,14 @@ impl<T: 'static + PageTable> SwapManager<T> for FifoSwapManager<T> {
         self.deque.push_back(addr);
     }
 
-    fn pop(&mut self, addr: usize) {
+    fn remove(&mut self, addr: usize) {
         let id = self.deque.iter()
             .position(|&x| x == addr)
             .expect("address not found");
         self.deque.remove(id);
     }
 
-    fn swap(&mut self) -> Option<Addr> {
+    fn pop(&mut self) -> Option<Addr> {
         self.deque.pop_front()
     }
 }
@@ -52,19 +52,20 @@ mod test {
     static mut PAGE: *mut MockPageTable = 0 as *mut _;
     static mut FIFO: *mut FifoSwapManager<MockPageTable> = 0 as *mut _;
 
-    fn pgfault_handler(pt: &mut MockPageTable, addr: Addr) {
+    fn page_fault_handler(pt: &mut MockPageTable, addr: Addr) {
         unsafe{ PGFAULT_COUNT += 1; }
         let fifo = unsafe{ &mut *FIFO };
-        if let Some(x) = fifo.swap() {
-            pt.unmap(x);
+        if !pt.map(addr) {  // is full?
+            pt.unmap(fifo.pop().unwrap());
+            pt.map(addr);
         }
-        pt.map(addr);
+        fifo.push(addr);
     }
 
     #[test]
     fn test() {
         use self::MemOp::{R, W};
-        let mut pt = MockPageTable::new(pgfault_handler);
+        let mut pt = MockPageTable::new(4, page_fault_handler);
         let mut fifo = FifoSwapManager::<MockPageTable>::new(
             unsafe{ &*(&pt as *const _) });
         unsafe {
diff --git a/crate/memory/src/swap/mock_page_table.rs b/crate/memory/src/swap/mock_page_table.rs
index ba5185f..b3f0088 100644
--- a/crate/memory/src/swap/mock_page_table.rs
+++ b/crate/memory/src/swap/mock_page_table.rs
@@ -5,10 +5,11 @@ pub struct MockPageTable {
     mapped_set: BTreeSet<Addr>,
     accessed_set: BTreeSet<Addr>,
     dirty_set: BTreeSet<Addr>,
-    pgfault_handler: PgfaultHandler,
+    page_fault_handler: PageFaultHandler,
+    capacity: usize,
 }
 
-type PgfaultHandler = fn(&mut MockPageTable, Addr);
+type PageFaultHandler = fn(&mut MockPageTable, Addr);
 
 impl PageTable for MockPageTable {
     fn accessed(&self, addr: Addr) -> bool {
@@ -20,18 +21,19 @@ impl PageTable for MockPageTable {
 }
 
 impl MockPageTable {
-    pub fn new(pgfault_handler: PgfaultHandler) -> Self {
+    pub fn new(capacity: usize, page_fault_handler: PageFaultHandler) -> Self {
         MockPageTable {
             mapped_set: BTreeSet::<Addr>::new(),
             accessed_set: BTreeSet::<Addr>::new(),
             dirty_set: BTreeSet::<Addr>::new(),
-            pgfault_handler,
+            page_fault_handler,
+            capacity,
         }
     }
     /// Read memory, mark accessed, trigger page fault if not present
     pub fn read(&mut self, addr: Addr) {
         while !self.mapped_set.contains(&addr) {
-            (self.pgfault_handler)(self, addr);
+            (self.page_fault_handler)(self, addr);
         }
         self.accessed_set.insert(addr);
 
@@ -39,14 +41,20 @@ impl MockPageTable {
     /// Write memory, mark accessed and dirty, trigger page fault if not present
     pub fn write(&mut self, addr: Addr) {
         while !self.mapped_set.contains(&addr) {
-            (self.pgfault_handler)(self, addr);
+            (self.page_fault_handler)(self, addr);
         }
         self.accessed_set.insert(addr);
         self.dirty_set.insert(addr);
     }
-    pub fn map(&mut self, addr: Addr) {
+    /// Map a page, return false if no more space
+    pub fn map(&mut self, addr: Addr) -> bool {
+        if self.mapped_set.len() == self.capacity {
+            return false;
+        }
         self.mapped_set.insert(addr);
+        true
     }
+    /// Unmap a page
     pub fn unmap(&mut self, addr: Addr) {
         self.mapped_set.remove(&addr);
     }
@@ -64,11 +72,11 @@ mod test {
 
     #[test]
     fn test() {
-        fn pgfault_handler(pt: &mut MockPageTable, addr: Addr) {
+        fn page_fault_handler(pt: &mut MockPageTable, addr: Addr) {
             unsafe{ PGFAULT_COUNT += 1; }
             pt.map(addr);
         }
-        let mut pt = MockPageTable::new(pgfault_handler);
+        let mut pt = MockPageTable::new(2, page_fault_handler);
 
         pt.map(0);
         pt.read(0);
@@ -81,6 +89,8 @@ mod test {
         assert!(pt.accessed(1));
         assert!(pt.dirty(1));
 
+        assert_eq!(pt.map(2), false);
+
         pt.unmap(0);
         pt.read(0);
         assert_pgfault_eq(2);
diff --git a/crate/memory/src/swap/mod.rs b/crate/memory/src/swap/mod.rs
index badc394..80b1e5a 100644
--- a/crate/memory/src/swap/mod.rs
+++ b/crate/memory/src/swap/mod.rs
@@ -11,9 +11,9 @@ trait SwapManager<T: PageTable> {
     /// Called when map a swappable page into the memory
     fn push(&mut self, addr: Addr);
     /// Called to delete the addr entry from the swap manager
-    fn pop(&mut self, addr: Addr);
+    fn remove(&mut self, addr: Addr);
     /// Try to swap out a page, return then victim
-    fn swap(&mut self) -> Option<Addr>;
+    fn pop(&mut self) -> Option<Addr>;
 }
 
 trait PageTable {