Switch to using pipes to implement has_version etc.

1 files changed, 107 insertions, 0 deletions

diff --git a/paludis/repositories/e/ebuild/utils/locked_pipe_command.cc b/paludis/repositories/e/ebuild/utils/locked_pipe_command.cc
new file mode 100644
index 000000000..eca37809d
--- /dev/null
+++ b/paludis/repositories/e/ebuild/utils/locked_pipe_command.cc
@@ -0,0 +1,107 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2007 Ciaran McCreesh
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <cstdlib>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <iostream>
+
+int
+main(int argc, char *argv[])
+{
+    if (argc != 3)
+    {
+        std::cerr << "Usage: " << argv[0] << " write_fd read_fd" << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    int write_fd(std::atoi(argv[1])), read_fd(std::atoi(argv[2]));
+    if (0 != ::lockf(write_fd, F_LOCK, 0))
+    {
+        std::cerr << "Error: " << argv[0] << ": lockf failed with " << ::strerror(errno) << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    /* copy stdin to the pipe read buffer */
+    char buf[1024];
+    int c, w;
+    while (((c = read(0, buf, 1024))) > 0)
+    {
+        char * buf_p(buf);
+        while (((w = write(write_fd, buf_p, c))) > 0)
+        {
+            buf_p += w;
+            c -= w;
+            if (c == 0)
+                break;
+        }
+        if (w == -1)
+        {
+            std::cerr << "Error: " << argv[0] << ": write failed with " << ::strerror(errno) << std::endl;
+            return EXIT_FAILURE;
+        }
+    }
+
+    if (c == -1)
+    {
+        std::cerr << "Error: " << argv[0] << ": read failed with " << ::strerror(errno) << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    /* append null to the pipe read buffer */
+    buf[0] = '\0';
+    while (((w = write(write_fd, buf, 1))) == 0)
+        sleep(0);
+    if (w == -1)
+    {
+        std::cerr << "Error: " << argv[0] << ": write failed with " << ::strerror(errno) << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    /* copy write buffer to stdout until we get a null, and discard that null */
+    while (((c = read(read_fd, buf, 1))) > 0)
+    {
+        if (buf[0] == '\0')
+            break;
+
+        while (((w = write(1, buf, c))) == 0)
+            sleep(0);
+        if (w == -1)
+        {
+            std::cerr << "Error: " << argv[0] << ": write failed with " << ::strerror(errno) << std::endl;
+            return EXIT_FAILURE;
+        }
+    }
+
+    if (c == -1)
+    {
+        std::cerr << "Error: " << argv[0] << ": read failed with " << ::strerror(errno) << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    if (0 != ::lockf(write_fd, F_ULOCK, 0))
+    {
+        std::cerr << "Error: " << argv[0] << ": lockf unlock failed with " << ::strerror(errno) << std::endl;
+        return EXIT_FAILURE;
+    }
+
+    return EXIT_SUCCESS;
+}
+