Add README

Cargo.toml

@@ -1,13 +1,15 @@
 [package]
 name = "readable-perms"
+description = "More usable UNIX file permissions interface"
+tags = ["unix", "fs", "permissions", "file", "filesystem", "file permissions", "linux", "mode_t", "chmod"]
 version = "0.1.0"
 authors = ["Avril <flanchan@cumallover.me>"]
 edition = "2018"
+license = "GPL-3.0-or-later"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
-
 # Ignore this, it is for regenerating the lookup table used on stable (needed due to lack of matching in `const fn`).
 # It is already included in this repo.
 # If you really want to rebuild it, `cargo test` will output it to `src/stable/mod.rs` lol.

README.md

@@ -0,0 +1,82 @@
+# Readable Unix Permissions
+
+Data types for the UNIX file permissions model. Convertable to and from `mode_t`.
+
+## Usage
+
+Crate is designed to give finer and more sane control over `mode_t`, so there are multiple ways of using the `Permissions` struct.
+
+All the below functions are `const fn` on nightly.
+
+### Creating from mode
+
+``` rust
+let perms = Permissions::from_mask(0o644); // Any value above 0u777 is truncated.
+```
+
+### Creating through builder-pattern
+
+You can add masks with `add_mask()`
+``` rust
+let perms = Permissions::new()
+	.add_mask(User::Owner, Bit::Read | Bit::Write)
+	.add_mask(User::Group, Bit::Read);
+```
+And remove them with `remove_mask()`
+
+``` rust
+let perms = Permissions::from_mask(0o777)
+	.remove_mask(User::Other, Bit::Write | Bit::Execute)
+	.remove_mask(User::Group, Bit::Write);
+```
+
+### Checking 
+You can check which modes are set with `has_mask()`.
+
+``` rust
+let perms = Permissions::from_mask(0o754);
+assert!(perms.has_mask(User::Owner, Bit::Mask));
+assert!(perms.has_mask(User::Group, Bit::Read | Bit::Execute));
+assert!(perms.has_mask(User::Other, Bit::Read));
+```
+
+We also derive `PartialEq<u32>`, to compare with `mode_t` directly.
+
+``` rust
+let perms = Permissions::from_mask(0o644);
+
+assert_eq!(perms, 0o644);
+```
+
+## Extension trait
+
+We also define an extension trait on target family `unix` that follows `std::os::unix::fs::PermissionsExt`.
+See [ext.rs] for details.
+
+[ext.rs]: ./src/ext.rs
+
+``` rust
+use readable_perms::PermissionsExt as UnixPermsExt;
+use std::os::unix::fs::PermissionsExt;
+
+fn do_thing(file: &mut std::fs::File)
+{
+	let perms = file.metadata().unwrap().permissions().unix();
+	println!("Perms are {}", perms);
+}
+```
+
+## Performance
+On nightly, most functions are `const fn` incuring no runtime cost for constant definitions. On stable, not so. Either way, we define a global `const` lookup table, so that conversions are as fast as a memory lookup.
+
+Adding and removing the masks is usually 1 or two bitwise operations. TODO: Benchmark these?
+
+### Benchmarks
+
+ | Type                  | Value                |
+ |-----------------------|----------------------|
+ | Conversions from mode | 159 ns/iter (+/- 15) |
+ | Conversions to mode   | 162 ns/iter (+/- 15) |
+
+# License
+GPL'd with <3

src/bench.rs

@@ -29,4 +29,3 @@ fn from_mask(b: &mut Bencher)
 	}
     });
 }
-

src/lib.rs

@@ -179,15 +179,15 @@ bitflags!{
     }
 }
 
-bitflags!{
+/*bitflags!{
-    // not supported, don't care
+// not supported, don't care
-    struct StickyBit: u32{
+struct StickyBit: u32{
-	const Empty = 0;
+const Empty = 0;
-	const Setuid = 0o40000;
+const Setuid = 0o40000;
-	const Setgid = 0o20000;
+const Setgid = 0o20000;
-	const SaveSwap = 0o10000;
+const SaveSwap = 0o10000;
     }
-}
+}*/
 
 /// Permissions struct in readable format
 #[derive(Debug, Clone, PartialEq, Eq, Hash, Copy, Ord, PartialOrd)]
@@ -212,7 +212,7 @@ pub struct Permissions
     /// Read, write, and execute mask for anyone else
     pub other: Bit,
     
-    _sticky: StickyBit, //idc about this either
+    u_mask: u32, 
 }
 
 /// The class of user that UNIX permissions care about
@@ -287,7 +287,8 @@ impl Permissions
 	    owner: Bit::None,
 	    group: Bit::None,
 	    other: Bit::None,
-	    _sticky: StickyBit::Empty,
+
+	    u_mask: 0u32,
 	}
     }
 }
@@ -309,15 +310,27 @@ impl Permissions
     }
 
     /// Convert into `mode_t` representation.
-    #[inline] #[cfg(nightly)]  pub const fn mask(&self) -> u32
+    #[inline] #[cfg(nightly)]  const fn mask_calc(&self) -> u32
     {
 	self.c_owner().mode() |
 	self.c_group().mode() |
 	self.c_other().mode()
     }
 
+    #[inline] #[cfg(nightly)] const fn into_calced(mut self) -> Self
+    {
+	self.u_mask = self.mask_calc();
+	self
+    }
+    
     /// Convert into `mode_t` representation.
-    #[inline] #[cfg(not(nightly))] pub fn mask(&self) -> u32
+    #[inline] pub const fn mask(&self) -> u32
+    {
+	self.u_mask
+    }
+    
+    /// Convert into `mode_t` representation.
+    #[inline] #[cfg(not(nightly))] fn mask_calc(&self) -> u32
     {
 	self.c_owner().mode() |
 	self.c_group().mode() |
@@ -332,8 +345,8 @@ impl Permissions
 	    group: Class::Group(Bit::Mask).mask_mode(bit),
 	    other: Class::Other(Bit::Mask).mask_mode(bit),
 
-	    _sticky: StickyBit::Empty,
+	    u_mask: 0,
-	}
+	}.into_calced()
     }
     
     /// Convert from `mode_t` representation.
@@ -348,7 +361,9 @@ impl Permissions
     /// For builder pattern
     #[inline] #[cfg(nightly)] pub const fn add_mask(self, class: User, bit: Bit) -> Self
     {
-	match class {
+	Self {
+	    u_mask: self.u_mask | class.mode(bit),
+	    ..match class {
 		User::Owner => {
 		    Self {
 			owner: Bit::from_bits_truncate(self.owner.bits() | bit.bits()),
@@ -369,6 +384,7 @@ impl Permissions
 		},
 	    }
 	}
+    }
     
     /// Consume and add a mask.
     ///
@@ -376,7 +392,9 @@ impl Permissions
     /// For builder pattern
     #[inline] #[cfg(not(nightly))] pub fn add_mask(self, class: User, bit: Bit) -> Self
     {
-	match class {
+	Self {
+	    u_mask: self.u_mask | class.mode(bit),
+	    ..match class {
 		User::Owner => {
 		    Self {
 			owner: Bit::from_bits_truncate(self.owner.bits() | bit.bits()),
@@ -386,17 +404,20 @@ impl Permissions
 		User::Group => {
 		    Self {
 			group: Bit::from_bits_truncate(self.group.bits() | bit.bits()),
+
 			..self
 		    }
 		},
 		User::Other => {
 		    Self {
 			other: Bit::from_bits_truncate(self.other.bits() | bit.bits()),
+
 			..self
 		    }
 		},
 	    }
 	}
+    }
 
     
     /// Consume and remove a mask.
@@ -405,7 +426,9 @@ impl Permissions
     /// For builder pattern
     #[inline] #[cfg(nightly)] pub const fn remove_mask(self, class: User, bit: Bit) -> Self
     {
-	match class {
+	Self{
+	    u_mask: self.u_mask & !class.mode(bit),
+	    ..match class {
 		User::Owner => {
 		    Self {
 			owner: Bit::from_bits_truncate(self.owner.bits() & !bit.bits()),
@@ -426,6 +449,7 @@ impl Permissions
 		},
 	    }
 	}
+    }
 
     
     /// Consume and remove a mask.
@@ -434,7 +458,9 @@ impl Permissions
     /// For builder pattern
     #[inline] #[cfg(not(nightly))] pub fn remove_mask(self, class: User, bit: Bit) -> Self
     {
-	match class {
+	Self {
+	    u_mask: self.u_mask & !class.mode(bit),
+	    ..match class {
 		User::Owner => {
 		    Self {
 			owner: Bit::from_bits_truncate(self.owner.bits() & !bit.bits()),
@@ -455,6 +481,7 @@ impl Permissions
 		},
 	    }
 	}
+    }
 
     /// Returns true if the specified mode mask is all present
     #[inline] #[cfg(nightly)]  pub const fn has_mask(&self, class: User, bit: Bit) -> bool
@@ -493,7 +520,8 @@ impl From<Permissions> for u32
 {
     #[inline] fn from(from: Permissions) -> Self
     {
-	from.mask() //can we not do the `MAP` here ;~;
+	debug_assert_eq!(from.mask_calc(), from.mask());
+	from.mask()
     }
 }
 
@@ -565,7 +593,7 @@ mod output {
 	    print_bit(to,&perm.group)?;
 	    write!(to, ", other: ")?;
 	    print_bit(to,&perm.other)?;
-	    write!(to, ", _sticky: StickyBit::Empty}}, ")?;
+	    write!(to, ", u_mask: {}}}, ", perm.mask_calc())?;
 	}
 	writeln!(to, "]")?;
 	Ok(())
@@ -659,6 +687,6 @@ impl std::fmt::Display for Permissions
 {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
     {
-	println!("0{}", self.mask())
+	write!(f, "0{}", self.mask())
     }
 }