[vala/staging] posix: Add CommandPipe as a sub-type of FILE

[Rico Tzschichholz <ricotz src gnome org>]

commit c9604b47adf545c431be866d833bb7167a3b6f1e
Author: Alistair Thomas <astavale yahoo co uk>
Date:   Mon Jun 25 10:06:10 2018 +0100

    posix: Add CommandPipe as a sub-type of FILE
    
    A FILE opened with popen() should be closed with pclose()
    This is enabled by adding CommandPipe as a sub-class of FILE
    
    Fixes https://gitlab.gnome.org/GNOME/vala/issues/645

 tests/Makefile.am                 |  1 +
 tests/posix/file-commandpipe.vala | 10 +++++++++
 vapi/posix.vapi                   | 45 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 55 insertions(+), 1 deletion(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 4ac9b94dc..39745e8c8 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -644,6 +644,7 @@ NON_NULL_TESTS = \
 
 LINUX_TESTS = \
        linux/bug793444.vala \
+       posix/file-commandpipe.vala \
        $(NULL)
 
 check-TESTS: $(TESTS) $(NON_NULL_TESTS)
diff --git a/tests/posix/file-commandpipe.vala b/tests/posix/file-commandpipe.vala
new file mode 100644
index 000000000..90ef10c0a
--- /dev/null
+++ b/tests/posix/file-commandpipe.vala
@@ -0,0 +1,10 @@
+void main () {
+       {
+               var pipe = Posix.FILE.popen ("sleep 0", "r");
+               var result = pipe.close ();
+               assert (result == 0);
+       }
+       {
+               new Posix.CommandPipe ("ls *");
+       }
+}
diff --git a/vapi/posix.vapi b/vapi/posix.vapi
index 93eb80b70..118e96d87 100644
--- a/vapi/posix.vapi
+++ b/vapi/posix.vapi
@@ -3074,8 +3074,11 @@ namespace Posix {
                [CCode (cname = "fdopen")]
                public static FILE? fdopen (int fildes, string mode);
                [CCode (cname = "popen")]
-               public static FILE? popen (string command, string mode);
+               public static CommandPipe? popen (string command, string mode);
 
+               [CCode (cname = "fclose")]
+               [DestroysInstance]
+               public int close ();
                [CCode (cname = "fprintf")]
                [PrintfFormat ()]
                public int printf (string format, ...);
@@ -3115,6 +3118,46 @@ namespace Posix {
        public static FILE stdout;
        public static FILE stdin;
 
+       /**
+        * A pipe to the given command run in a child process
+        *
+        * This is a binding to popen () and pclose (). popen () is the equivalent
+        * of pipe (), fork (), dup2 () and then exec () in a single operation
+        */
+       [Compact]
+       [CCode (cname = "FILE", free_function = "pclose", cheader_filename = "stdio.h")]
+       [Version (since = "vala-0.44")]
+       public class CommandPipe : FILE {
+               /**
+                * A pipe to the given command run in a child process
+                *
+                * @param command The command to run
+                * @param mode Either 'r' or 'w'. 'r' creates a pipe to the command's
+                * STDOUT, the command's STDIN is the same as the parent process.
+                * 'w' creates a pipe to the command's STDIN, the command's STDOUT is
+                * the same as the parent process
+                */
+               [CCode (cname = "popen")]
+               public CommandPipe (string command, string mode = "r");
+               /**
+                * Explicitly close the pipe
+                *
+                * Explicitly closing the pipe is only necessary when checking the
+                * termination status of the command language interpreter. Normally
+                * Vala will generate code to automatically close the pipe when the
+                * CommandPipe instance goes out of scope
+                *
+                * CommandPipe.close () is synchronous and will return when the child
+                * process has terminated
+                *
+                * @return The termination status of the command language interpreter
+                * or -1 if status could not be obtained. errno will be set if -1
+                */
+               [CCode (cname = "pclose")]
+               [DestroysInstance]
+               public int close ();
+       }
+
        [CCode (cheader_filename = "stdio.h")]
        public void perror (string s);