From 852120e23a3d88fc25d229690b7a78c8fba4f5b2 Mon Sep 17 00:00:00 2001
From: Sergio Benitez <sbenitez@mit.edu>
Date: Thu, 17 Mar 2016 19:43:58 -0700
Subject: [PATCH] Forgot a file, it seems.

---
 lib/src/router.rs | 99 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 lib/src/router.rs

diff --git a/lib/src/router.rs b/lib/src/router.rs
new file mode 100644
index 00000000..33c03496
--- /dev/null
+++ b/lib/src/router.rs
@@ -0,0 +1,99 @@
+use method::Method;
+use std::path::{Path, PathBuf, Component};
+use std::collections::hash_map::HashMap;
+
+pub struct Router {
+    paths: Vec<PathBuf> // for now, to check for collisions
+}
+
+fn is_variadic(c: &Component) -> bool {
+    match c {
+        &Component::Normal(ref comp) => comp.to_str().unwrap().starts_with("<"),
+        _ => false
+    }
+}
+
+#[inline]
+fn routes_collide(n: usize, a: &Path, b: &Path) -> bool {
+    let mut matches = 0;
+
+    let mut a_components = a.components();
+    let mut b_components = b.components();
+
+    while let Some(ref c1) = a_components.next() {
+        if let Some(ref c2) = b_components.next() {
+            if c1 == c2 {
+                matches += 1;
+            } else if is_variadic(c1) || is_variadic(c2) {
+                matches += 1;
+            }
+        }
+    }
+
+    // println!("Checked {:?} against {:?}: {}/{}", a, b, matches, n);
+    matches == n
+}
+
+// TODO: Are /hello and /hello/ the same? Or not? Currently, they're treated as
+// such by Path, which is passed on to the collisions stuff.
+impl Router {
+    pub fn new() -> Router {
+        Router {
+            paths: Vec::new()
+        }
+    }
+
+    pub fn add_route(&mut self, method: Method, base: &str, route: &str) {
+        // Allocate enough space for the worst case.
+        let mut deduped = String::with_capacity(base.len() + route.len() + 1);
+
+        let mut last = '\0';
+        for c in base.chars().chain("/".chars()).chain(route.chars()) {
+            if !(last == '/' && c == '/') {
+                deduped.push(c);
+            }
+
+            last = c;
+        }
+
+        let mut path = PathBuf::from(deduped);
+        println!("Mounted: {:?}", path);
+        self.paths.push(path);
+    }
+
+    pub fn has_collisions(&self) -> bool {
+        let mut map: HashMap<usize, Vec<&Path>> = HashMap::new();
+
+        for route in &self.paths {
+            let num_components = route.components().count();
+            println!("Found {} for {:?}", num_components, route);
+
+            let mut list = if map.contains_key(&num_components) {
+                map.get_mut(&num_components).unwrap()
+            } else {
+                map.insert(num_components, Vec::new());
+                map.get_mut(&num_components).unwrap()
+            };
+
+            list.push(route.as_path());
+        }
+
+        let mut result = false;
+        for (num_components, routes) in map.iter() {
+            for i in 0..routes.len() {
+                for j in 0..routes.len() {
+                    if i == j { continue }
+
+                    let a_route = &routes[i];
+                    let b_route = &routes[j];
+                    if routes_collide(*num_components, a_route, b_route) {
+                        result = true;
+                        println!("{:?} and {:?} collide!", a_route, b_route);
+                    }
+                }
+            }
+        }
+
+        result
+    }
+}