From 7e8ee5ed9cad6484e9f13f81731b102ced58402e Mon Sep 17 00:00:00 2001
From: Adam Carpenter <gitlab@53hor.net>
Date: Tue, 9 Jul 2019 15:14:04 -0400
Subject: Init.

---
 meap/meap-code/ch4/ch4-short-lived-strategy.rs | 82 ++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100755 meap/meap-code/ch4/ch4-short-lived-strategy.rs

(limited to 'meap/meap-code/ch4/ch4-short-lived-strategy.rs')

diff --git a/meap/meap-code/ch4/ch4-short-lived-strategy.rs b/meap/meap-code/ch4/ch4-short-lived-strategy.rs
new file mode 100755
index 0000000..1082469
--- /dev/null
+++ b/meap/meap-code/ch4/ch4-short-lived-strategy.rs
@@ -0,0 +1,82 @@
+#![allow(unused_variables)]
+
+#[derive(Debug)]
+struct CubeSat {
+  id: u64,
+}
+
+#[derive(Debug)]
+struct Mailbox {
+  messages: Vec<Message>,
+}
+
+#[derive(Debug)]
+struct Message {
+    to: u64,
+    content: String,
+}
+
+struct GroundStation {}
+
+impl Mailbox {
+    fn post(&mut self, msg: Message) {
+        self.messages.push(msg);
+    }
+
+    fn deliver(&mut self, recipient: &CubeSat) -> Option<Message> {
+        for i in 0..self.messages.len() {
+            if self.messages[i].to == recipient.id {
+                let msg = self.messages.remove(i);
+                return Some(msg);
+            }
+        }
+
+        None
+    }
+}
+
+impl GroundStation {
+    fn connect(&self, sat_id: u64) -> CubeSat {
+        CubeSat {
+            id: sat_id, 
+        }
+    }
+
+    fn send(&self, mailbox: &mut Mailbox, msg: Message) {
+        mailbox.post(msg);
+    }
+}
+
+impl CubeSat {
+    fn recv(&self, mailbox: &mut Mailbox) -> Option<Message> {
+        mailbox.deliver(&self)
+    }
+}
+
+fn fetch_sat_ids() -> Vec<u64> {
+  vec![1,2,3]
+}
+
+
+fn main() {
+  let mut mail = Mailbox { messages: vec![] };
+
+  let base = GroundStation {};
+
+  let sat_ids = fetch_sat_ids();
+
+  for sat_id in sat_ids {
+    let sat = base.connect(sat_id);
+    let msg = Message { to: sat_id, content: String::from("hello") };
+    base.send(&mut mail, msg);
+  }
+
+  let sat_ids = fetch_sat_ids();
+
+  for sat_id in sat_ids {
+    let sat = base.connect(sat_id);
+    
+    let msg = sat.recv(&mut mail);
+    println!("{:?}: {:?}", sat, msg);
+  }
+}
\ No newline at end of file
-- 
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