Initial commit

src/utils.rs

@@ -0,0 +1,99 @@
+use std::sync::{Condvar, Mutex};
+
+pub fn normalize_title(input: &str) -> String {
+    let mut out = String::with_capacity(input.len());
+    for ch in input.chars() {
+        if ch.is_ascii_alphanumeric() {
+            out.push(ch.to_ascii_lowercase());
+        } else if ch.is_whitespace() {
+            out.push(' ');
+        } else {
+            out.push(' ');
+        }
+    }
+    collapse_whitespace(&out)
+}
+
+pub fn sanitize_filename(input: &str) -> String {
+    let mut out = String::with_capacity(input.len());
+    for ch in input.chars() {
+        if matches!(ch, '<' | '>' | ':' | '"' | '/' | '\\' | '|' | '?' | '*') {
+            out.push(' ');
+        } else {
+            out.push(ch);
+        }
+    }
+    collapse_whitespace(&out)
+}
+
+pub fn collapse_whitespace(input: &str) -> String {
+    let mut out = String::with_capacity(input.len());
+    let mut last_space = false;
+    for ch in input.chars() {
+        if ch.is_whitespace() {
+            if !last_space {
+                out.push(' ');
+                last_space = true;
+            }
+        } else {
+            last_space = false;
+            out.push(ch);
+        }
+    }
+    out.trim().to_string()
+}
+
+pub struct Semaphore {
+    state: Mutex<usize>,
+    cvar: Condvar,
+}
+
+impl Semaphore {
+    pub fn new(count: usize) -> Self {
+        Self {
+            state: Mutex::new(count),
+            cvar: Condvar::new(),
+        }
+    }
+
+    pub fn acquire(&self) -> SemaphoreGuard<'_> {
+        let mut count = self.state.lock().unwrap();
+        while *count == 0 {
+            count = self.cvar.wait(count).unwrap();
+        }
+        *count -= 1;
+        SemaphoreGuard { sem: self }
+    }
+}
+
+pub struct SemaphoreGuard<'a> {
+    sem: &'a Semaphore,
+}
+
+impl Drop for SemaphoreGuard<'_> {
+    fn drop(&mut self) {
+        let mut count = self.sem.state.lock().unwrap();
+        *count += 1;
+        self.sem.cvar.notify_one();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{collapse_whitespace, normalize_title, sanitize_filename};
+
+    #[test]
+    fn normalizes_title() {
+        assert_eq!(normalize_title("The.Matrix!!"), "the matrix");
+    }
+
+    #[test]
+    fn sanitizes_filename() {
+        assert_eq!(sanitize_filename("Bad:Name/Here"), "Bad Name Here");
+    }
+
+    #[test]
+    fn collapses_whitespace() {
+        assert_eq!(collapse_whitespace("a   b  c"), "a b c");
+    }
+}