win32: move code to fork (de)compressor to a function

Use a new common function, mingw_fork_compressor(), to implement
fork_transformer() in open_transformer.c and vfork_compressor()
in tar.c.

Saves 160 bytes.

1 files changed, 22 insertions, 0 deletions

diff --git a/win32/popen.c b/win32/popen.c
index 0da5cde23..8810b8de0 100644
--- a/win32/popen.c
+++ b/win32/popen.c
@@ -306,3 +306,25 @@ int mingw_pclose(FILE *fp)
 
         return (ret == WAIT_OBJECT_0) ? 0 : -1;
 }
+
+/* Used with mode "w" and a compressor when creating a compressed tar
+ * file; with mode "r" and a decompressor in open_transformer. */
+pid_t mingw_fork_compressor(int fd, const char *compressor, const char *mode)
+{
+        char *cmd;
+        int fd1;
+        pid_t pid;
+
+        if (find_applet_by_name(compressor) >= 0)
+                cmd = xasprintf("%s --busybox %s -cf -", bb_busybox_exec_path,
+                                        compressor);
+        else
+                cmd = xasprintf("%s -cf -", compressor);
+
+        if ((fd1 = mingw_popen_fd(cmd, mode, fd, &pid)) == -1)
+                bb_perror_msg_and_die("can't execute '%s'", compressor);
+
+        free(cmd);
+        xmove_fd(fd1, fd);
+        return pid;
+}