Merge #189

189: Allow playground defaults r=Dylan-DPC a=kinggoesgaming

**I'm submitting a ...**
  - [ ] bug fix
  - [x] feature enhancement
  - [ ] deprecation or removal
  - [ ] refactor

# Description
Allow compatibility with play.integer32.com and play.rust-lang.org

# Motivation
Allows people to use `uuid` in interactive code snippets

# Tests
Current tests passing

# Related Issue(s)
Supercedes #155

Cargo.toml

@@ -36,6 +36,11 @@ default = ["std"]
 std = []
 use_std = ["std"] # Compatibility shim for 0.5 and earlier
 v1 = []
-v3 = ["md5"]
+v3 = ["md5", "rand"]
 v4 = ["rand"]
-v5 = ["sha1"]
+v5 = ["sha1", "rand"]
+
+# Get features picked up by the Integer 32 playground. Not public API.
+#
+# https://play.rust-lang.org
+playground = ["serde", "v1", "v3", "v4", "v5"]

src/lib.rs

@@ -402,12 +402,30 @@ impl Uuid {
  /// Note that not all versions can be generated currently and `None` will be
  /// returned if the specified version cannot be generated.
  ///
+ /// To generate a random UUID (`UuidVersion::Md5`), then the `v3`
+ /// feature must be enabled for this crate.
+ ///
  /// To generate a random UUID (`UuidVersion::Random`), then the `v4`
  /// feature must be enabled for this crate.
+ ///
+ /// To generate a random UUID (`UuidVersion::Sha1`), then the `v5`
+ /// feature must be enabled for this crate.
  pub fn new(v: UuidVersion) -> Option<Uuid> {
+ // Why 23? Ascii has roughly 6bit randomness per 8bit.
+ // So to reach 128bit at-least 21.333 (128/6) Bytes are required.
+ #[cfg(any(feature = "v3", feature = "v5"))]
+ let iv: String = {
+ use rand::Rng;
+ rand::thread_rng().gen_ascii_chars().take(23).collect()
+ };
+
  match v {
+ #[cfg(feature = "v3")]
+ UuidVersion::Md5 => Some(Uuid::new_v3(&NAMESPACE_DNS, &*iv)),
  #[cfg(feature = "v4")]
  UuidVersion::Random => Some(Uuid::new_v4()),
+ #[cfg(feature = "v5")]
+ UuidVersion::Sha1 => Some(Uuid::new_v5(&NAMESPACE_DNS, &*iv)),
  _ => None,
  }
  }
@@ -1106,7 +1124,7 @@ impl<'a> fmt::Display for Hyphenated<'a> {
 }
 
 macro_rules! hyphenated_write {
- ($f: expr, $format: expr, $bytes: expr) => {{
+ ($f:expr, $format:expr, $bytes:expr) => {{
  let data1 = u32::from($bytes[0]) << 24 | u32::from($bytes[1]) << 16
  | u32::from($bytes[2]) << 8 | u32::from($bytes[3]);
 
@@ -1332,6 +1350,13 @@ mod tests {
 
  #[test]
  fn test_new() {
+ if cfg!(feature = "v3") {
+ let u = Uuid::new(UuidVersion::Md5);
+ assert!(u.is_some(), "{:?}", u);
+ assert_eq!(u.unwrap().get_version().unwrap(), UuidVersion::Md5);
+ } else {
+ assert_eq!(Uuid::new(UuidVersion::Md5), None);
+ }
  if cfg!(feature = "v4") {
  let uuid1 = Uuid::new(UuidVersion::Random).unwrap();
  let s = uuid1.simple().to_string();
@@ -1341,12 +1366,17 @@ mod tests {
  } else {
  assert!(Uuid::new(UuidVersion::Random).is_none());
  }
+ if cfg!(feature = "v5") {
+ let u = Uuid::new(UuidVersion::Sha1);
+ assert!(u.is_some(), "{:?}", u);
+ assert_eq!(u.unwrap().get_version().unwrap(), UuidVersion::Sha1);
+ } else {
+ assert_eq!(Uuid::new(UuidVersion::Sha1), None);
+ }
 
  // Test unsupported versions
  assert_eq!(Uuid::new(UuidVersion::Mac), None);
  assert_eq!(Uuid::new(UuidVersion::Dce), None);
- assert_eq!(Uuid::new(UuidVersion::Md5), None);
- assert_eq!(Uuid::new(UuidVersion::Sha1), None);
  }
 
  #[cfg(feature = "v1")]
@@ -1624,7 +1654,7 @@ mod tests {
  let u = test_util::new();
 
  macro_rules! check {
- ($buf: ident, $format: expr, $target: expr, $len: expr, $cond: expr) => {
+ ($buf:ident, $format:expr, $target:expr, $len:expr, $cond:expr) => {
  $buf.clear();
  write!($buf, $format, $target).unwrap();
  assert!(buf.len() == $len);