feat: allows getting the terminal size of all standard streams, or ju…

…st particular ones

`dimensions` will now attempt to poll all three standard streams to find
the terminal size. `diminensions_{stdout,stderr,stdin}` have also been
added to only poll a particular stream.

`dimensions_stdout` is the equivilant of `term_size::dimensions` prior
to this release

src/lib.rs

@@ -19,7 +19,7 @@ extern crate kernel32;
 #[cfg(target_os = "windows")]
 extern crate winapi;
 
-pub use platform::dimensions;
+pub use platform::{dimensions, dimensions_stdout, dimensions_stdin, dimensions_stderr};
 
 #[cfg(any(target_os = "linux",
           target_os = "android",
@@ -33,7 +33,7 @@ pub use platform::dimensions;
           target_os = "solaris"))]
 mod platform {
     use std::mem::zeroed;
-    use libc::{STDOUT_FILENO, c_int, c_ulong, winsize};
+    use libc::{STDOUT_FILENO, STDIN_FILENO, STDERR_FILENO, c_int, c_ulong, winsize};
 
     // Unfortunately the actual command is not standardised...
     #[cfg(any(target_os = "linux", target_os = "android"))]
@@ -55,24 +55,118 @@ mod platform {
         fn ioctl(fd: c_int, request: c_ulong, ...) -> c_int;
     }
 
-    /// Runs the ioctl command. Returns (0, 0) if output is not to a terminal, or
+    /// Runs the ioctl command. Returns (0, 0) if all of the streams are not to a terminal, or
     /// there is an error. (0, 0) is an invalid size to have anyway, which is why
     /// it can be used as a nil value.
-    unsafe fn get_dimensions() -> winsize {
+    unsafe fn get_dimensions_any() -> winsize {
         let mut window: winsize = zeroed();
-        let result = ioctl(STDOUT_FILENO, TIOCGWINSZ, &mut window);
+        let mut result = ioctl(STDOUT_FILENO, TIOCGWINSZ, &mut window);
 
         if result == -1 {
-            zeroed()
-        } else {
-            window
+            window = zeroed();
+            result = ioctl(STDIN_FILENO, TIOCGWINSZ, &mut window);
+            if result == -1 {
+                window = zeroed();
+                result = ioctl(STDERR_FILENO, TIOCGWINSZ, &mut window);
+                if result == -1 {
+                    return zeroed();
+                }
+            }
         }
+        window
     }
 
-    /// Query the current processes's output, returning its width and height as a
-    /// number of characters. Returns `None` if the output isn't to a terminal.
+    /// Runs the ioctl command. Returns (0, 0) if the output is not to a terminal, or
+    /// there is an error. (0, 0) is an invalid size to have anyway, which is why
+    /// it can be used as a nil value.
+    unsafe fn get_dimensions_out() -> winsize {
+        let mut window: winsize = zeroed();
+        let result = ioctl(STDOUT_FILENO, TIOCGWINSZ, &mut window);
+
+        if result != -1 {
+            return window;
+        }
+        zeroed()
+    }
+
+    /// Runs the ioctl command. Returns (0, 0) if the input is not to a terminal, or
+    /// there is an error. (0, 0) is an invalid size to have anyway, which is why
+    /// it can be used as a nil value.
+    unsafe fn get_dimensions_in() -> winsize {
+        let mut window: winsize = zeroed();
+        let result = ioctl(STDIN_FILENO, TIOCGWINSZ, &mut window);
+
+        if result != -1 {
+            return window;
+        }
+        zeroed()
+    }
+
+    /// Runs the ioctl command. Returns (0, 0) if the error is not to a terminal, or
+    /// there is an error. (0, 0) is an invalid size to have anyway, which is why
+    /// it can be used as a nil value.
+    unsafe fn get_dimensions_err() -> winsize {
+        let mut window: winsize = zeroed();
+        let result = ioctl(STDERR_FILENO, TIOCGWINSZ, &mut window);
+
+        if result != -1 {
+            return window;
+        }
+        zeroed()
+    }
+
+    /// Query the current processes's output (`stdout`), input (`stdin`), and error (`stderr`) in
+    /// that order, in the attempt to dtermine terminal width. If one of those streams is actually
+    /// a tty, this function returns its width and height as a number of characters.
+    ///
+    /// If *all* of the streams are not ttys or return any errors this function will return `None`.
     pub fn dimensions() -> Option<(usize, usize)> {
-        let w = unsafe { get_dimensions() };
+        let w = unsafe { get_dimensions_any() };
+
+        if w.ws_col == 0 || w.ws_row == 0 {
+            None
+        } else {
+            Some((w.ws_col as usize, w.ws_row as usize))
+        }
+    }
+
+    /// Query the current processes's output (`stdout`) *only*, in the attempt to dtermine
+    /// terminal width. If that streams is actually a tty, this function returns its width
+    /// and height as a number of characters.
+    ///
+    /// If *all* of the streams are not ttys or return any errors this function will return `None`.
+    pub fn dimensions_stdout() -> Option<(usize, usize)> {
+        let w = unsafe { get_dimensions_out() };
+
+        if w.ws_col == 0 || w.ws_row == 0 {
+            None
+        } else {
+            Some((w.ws_col as usize, w.ws_row as usize))
+        }
+    }
+
+    /// Query the current processes's input (`stdin`) *only*, in the attempt to dtermine
+    /// terminal width. If that streams is actually a tty, this function returns its width
+    /// and height as a number of characters.
+    ///
+    /// If *all* of the streams are not ttys or return any errors this function will return `None`.
+    pub fn dimensions_stdin() -> Option<(usize, usize)> {
+        let w = unsafe { get_dimensions_in() };
+
+        if w.ws_col == 0 || w.ws_row == 0 {
+            None
+        } else {
+            Some((w.ws_col as usize, w.ws_row as usize))
+        }
+    }
+
+    /// Query the current processes's error output (`stderr`) *only*, in the attempt to dtermine
+    /// terminal width. If that streams is actually a tty, this function returns its width
+    /// and height as a number of characters.
+    ///
+    /// If *all* of the streams are not ttys or return any errors this function will return `None`.
+    pub fn dimensions_stderr() -> Option<(usize, usize)> {
+        let w = unsafe { get_dimensions_err() };
 
         if w.ws_col == 0 || w.ws_row == 0 {
             None
@@ -87,6 +181,8 @@ mod platform {
     use kernel32::{GetConsoleScreenBufferInfo, GetStdHandle};
     use winapi::{CONSOLE_SCREEN_BUFFER_INFO, COORD, SMALL_RECT, STD_OUTPUT_HANDLE};
 
+    /// Query the current processes's output, returning its width and height as a
+    /// number of characters. Returns `None` if the output isn't to a terminal.
     pub fn dimensions() -> Option<(usize, usize)> {
         let null_coord = COORD{
             X: 0,