concepts: require two Post approvals

[learn-rust.git] / concepts / src / lib.rs

diff --git a/concepts/src/lib.rs b/concepts/src/lib.rs
index ca0624142dea4d751e4506184bf84508de7e0696..b0839ad391739cb186adcf2bb81c97484c5a3dfe 100644 (file)
--- a/concepts/src/lib.rs
+++ b/concepts/src/lib.rs
@@ -110,14 +110,14 @@ impl Iterator for Counter5 {
 }
 
 pub struct Post {
 }
 
 pub struct Post {

-    state: Option<Box<dyn State>>,
+    state: Box<dyn State>,

     content: String,
 }
 
 impl Post {
     pub fn new() -> Post {
         Post {
     content: String,
 }
 
 impl Post {
     pub fn new() -> Post {
         Post {

-            state: Some(Box::new(Draft {})),
+            state: Box::new(Draft {}),

             content: String::new(),
         }
     }
             content: String::new(),
         }
     }


@@ -127,27 +127,26 @@ impl Post {
     }
 
     pub fn content(&self) -> &str {
     }
 
     pub fn content(&self) -> &str {

-        // as_ref() converts Option<Box<State>> to Option<&Box<State>>
-        // state can never be None, all state transitions return a new one
-        self.state.as_ref().unwrap().content(self)
+        self.state.content(self)

     }
 
     pub fn request_review(&mut self) {
     }
 
     pub fn request_review(&mut self) {

-        if let Some(s) = self.state.take() {
-            self.state = Some(s.request_review());
-        }
+        self.state = self.state.request_review();

     }
 
     pub fn approve(&mut self) {
     }
 
     pub fn approve(&mut self) {

-        if let Some(s) = self.state.take() {
-            self.state = Some(s.approve());
-        }
+        self.state = self.state.approve();
+    }
+
+    pub fn reject(&mut self) {
+        self.state = self.state.reject();

     }
 }
 
 trait State {
     }
 }
 
 trait State {

-    fn request_review(self: Box::<Self>) -> Box<dyn State>;
-    fn approve(self: Box::<Self>) -> Box<dyn State>;
+    fn request_review(&self) -> Box<dyn State>;
+    fn approve(&mut self) -> Box<dyn State>;
+    fn reject(&self) -> Box<dyn State>;

 
     #[allow(unused_variables)]
     fn content<'a>(&self, post: &'a Post) -> &'a str {
 
     #[allow(unused_variables)]
     fn content<'a>(&self, post: &'a Post) -> &'a str {


@@ -157,36 +156,56 @@ trait State {
 
 struct Draft {}
 impl State for Draft {
 
 struct Draft {}
 impl State for Draft {

-    fn request_review(self: Box::<Self>) -> Box<dyn State> {
-        Box::new(PendingReview {})
+    fn request_review(&self) -> Box<dyn State> {
+        Box::new(PendingReview {acks: 0})

     }
 
     }
 

-    fn approve(self: Box::<Self>) -> Box<dyn State> {
-        self
+    fn approve(&mut self) -> Box<dyn State> {
+        // don't change state
+        Box::new(Self {})

     }
     }

+
+    fn reject(&self) -> Box<dyn State> {
+        Box::new(Self {})
+    }
+}
+
+struct PendingReview {
+    acks: u32,

 }
 
 }
 

-struct PendingReview {}

 impl State for PendingReview {
 impl State for PendingReview {

-    fn request_review(self: Box::<Self>) -> Box<dyn State> {
-        self
+    fn request_review(&self) -> Box<dyn State> {
+        Box::new(Self {acks: self.acks})

     }
 
     }
 

-    fn approve(self: Box::<Self>) -> Box<dyn State> {
-        Box::new(Published {})
+    fn approve(&mut self) -> Box<dyn State> {
+        if self.acks >= 1 {
+            Box::new(Published {})
+        } else {
+            Box::new(Self {acks: self.acks + 1})
+        }
+    }
+
+    fn reject(&self) -> Box<dyn State> {
+        Box::new(Draft {})

     }
 }
 
 struct Published {}
 impl State for Published {
     }
 }
 
 struct Published {}
 impl State for Published {

-    fn request_review(self: Box::<Self>) -> Box<dyn State> {
-        self
+    fn request_review(&self) -> Box<dyn State> {
+        Box::new(Self {})

     }
 
     }
 

-    fn approve(self: Box::<Self>) -> Box<dyn State> {
+    fn approve(&mut self) -> Box<dyn State> {

         Box::new(Published {})
     }
 
         Box::new(Published {})
     }
 

+    fn reject(&self) -> Box<dyn State> {
+        Box::new(Self {})
+    }
+

     fn content<'a>(&self, post: &'a Post) -> &'a str {
         &post.content
     }
     fn content<'a>(&self, post: &'a Post) -> &'a str {
         &post.content
     }