From 1c3e06f29ad59c084c00725bf7041c2af126b22d Mon Sep 17 00:00:00 2001
From: Matias Linares <matiaslina@openmailbox.org>
Date: Sun, 15 Nov 2015 21:21:23 -0300
Subject: Clean of zombie process.

The spawn of process within the exec_cmd function now are handled by a new
function (collect_zombies).

For reference, this code was taken from the _zombie_ crate.
---
 Cargo.lock     | 11 ++++++++---
 src/command.rs | 40 ++++++++++++----------------------------
 src/dotwm.rs   |  4 +++-
 src/main.rs    |  3 ++-
 4 files changed, 25 insertions(+), 33 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 4058f90..b881a57 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,8 +2,8 @@
 name = "dotwm"
 version = "0.1.0"
 dependencies = [
- "libc 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "x11 2.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "x11 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -11,6 +11,11 @@ name = "libc"
 version = "0.1.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "libc"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "pkg-config"
 version = "0.3.6"
@@ -18,7 +23,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "x11"
-version = "2.2.0"
+version = "2.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "libc 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/src/command.rs b/src/command.rs
index fe42b22..09259af 100644
--- a/src/command.rs
+++ b/src/command.rs
@@ -2,10 +2,11 @@
 //!
 use std::ffi::OsStr;
 use std::process::{Command,Child};
-use std::io::{Result, Error, ErrorKind};
+use std::io::Result;
 
 use libc::c_int;
 use libc::pid_t;
+use std::ptr;
 
 const WNOHANG: c_int = 0x00000001;
 
@@ -14,34 +15,17 @@ extern {
     pub fn waitpid(pid: pid_t, stat_loc: *mut c_int, options: c_int) -> pid_t;
 }
 
-/// Extension to the Child struct that allows to check the status without block the
-/// current thread.
-pub trait ChildExt {
-    fn wait_nohang(&mut self) -> Result<bool>;
-}
-
-impl ChildExt for Child {
-    /// Checks if the calling child is a zombie and try to kill it, returning
-    /// if it was killed or not.
-    fn wait_nohang(&mut self) -> Result<bool> {
-        let mut stat = 0i32;
-        let pid = unsafe { waitpid(self.id() as i32, &mut stat, WNOHANG) };
-        if pid < 0 {
-            Err(Error::new(ErrorKind::NotFound, format!("pid not found {}", pid)))
-        } else {
-            if pid > 0 {
-                Ok(self.wait()
-                    .map(|x| {
-                        x.success()
-                    }).unwrap_or(false))
-            } else {
-                Ok(false)
-            }
-        }
-    }
-}
-
 /// Executes the given command.
 pub fn exec_cmd<S: AsRef<OsStr>>(program: S, args: &[S]) -> Result<Child> {
     Command::new(program).args(args).spawn()
 }
+
+/// Collect all the zombies. There's no need to add another dependency for this
+/// since it's trivial to implement.
+///
+/// See https://github.com/Kintaro/zombie for reference.
+pub fn collect_zombies() {
+    unsafe { 
+        while waitpid(-1, ptr::null_mut(), WNOHANG) > 0 {}
+    };
+}
diff --git a/src/dotwm.rs b/src/dotwm.rs
index e94b17f..d528899 100644
--- a/src/dotwm.rs
+++ b/src/dotwm.rs
@@ -29,10 +29,12 @@ unsafe extern "C" fn error_handler(d: *mut Display, evptr: *mut XErrorEvent) ->
 }
 
 pub struct DotWM {
+    /// Reference to the X display.
     pub display: *mut Display,
+    /// References to all the windows.
+    pub window_list: Vec<XWindow>,
     // Map with the keys as (key, mod)
     cw_idx: usize,
-    pub window_list: Vec<XWindow>,
 }
 
 /// DotWM state.
diff --git a/src/main.rs b/src/main.rs
index 02df6fd..4a0c545 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,7 +7,7 @@ pub mod dotwm;
 pub mod event;
 
 use dotwm::DotWM;
-use command::exec_cmd;
+use command::{exec_cmd,collect_zombies};
 use event::{Event,next_event};
 
 use safe_x11::grab_key;
@@ -157,5 +157,6 @@ fn main() {
             },
             _ => (),
         }
+        collect_zombies();
     }
 }
-- 
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