Revert shared_ptr<io_data_t> changes until kinks are ironed out

https://github.com/fish-shell/fish-shell/pull/487

Revert "Merge branch 'oo-io' of git://github.com/xiaq/fish-shell into xiaq-oo-io"

This reverts commit f3c8f535a48d5fdd518bd60879ade948bc8be7e6, reversing
changes made to b02f6cf3bc4343cf3e068dee3cb46de7139a5a27.

Also reverts ac023f7588e562a03fdea7fd2feda487f18827c7 and a79d3c680c9548566309121630dadc94e48934c4

1 files changed, 25 insertions, 12 deletions

diff --git a/io.h b/io.h
index 34dc242b..5b77838a 100644
--- a/io.h
+++ b/io.h
@@ -20,10 +20,9 @@ private:
     /** buffer to save output in for IO_BUFFER. Note that in the original fish, the buffer was a pointer to a buffer_t stored in the param2 union down below, and when an io_data_t was duplicated the pointer was copied so that two io_data_ts referenced the same buffer. It's not clear to me how this was ever cleaned up correctly. But it's important that they share the same buffer for reasons I don't yet understand either. We can get correct sharing and cleanup with shared_ptr. */
     shared_ptr<std::vector<char> > out_buffer;
 
-    /* No assignment or copying allowed */
-    io_data_t(const io_data_t &rhs);
+    /* No assignment allowed */
     void operator=(const io_data_t &rhs);
-    
+
 public:
     /** Type of redirect */
     int io_mode;
@@ -108,32 +107,46 @@ public:
     {
     }
 
+    io_data_t(const io_data_t &rhs) :
+        out_buffer(rhs.out_buffer),
+        io_mode(rhs.io_mode),
+        fd(rhs.fd),
+        param1(rhs.param1),
+        param2(rhs.param2),
+        filename_cstr(rhs.filename_cstr ? strdup(rhs.filename_cstr) : NULL),
+        is_input(rhs.is_input)
+    {
+    }
+
     ~io_data_t()
     {
         free((void *)filename_cstr);
     }
 };
 
-class io_chain_t : public std::vector<shared_ptr<io_data_t> >
+class io_chain_t : public std::vector<io_data_t *>
 {
 public:
     io_chain_t();
-    io_chain_t(const shared_ptr<io_data_t> &);
+    io_chain_t(io_data_t *);
 
-    void remove(const shared_ptr<const io_data_t> &element);
+    void remove(const io_data_t *element);
     io_chain_t duplicate() const;
     void duplicate_prepend(const io_chain_t &src);
     void destroy();
 
-    shared_ptr<const io_data_t> get_io_for_fd(int fd) const;
-    shared_ptr<io_data_t> get_io_for_fd(int fd);
+    const io_data_t *get_io_for_fd(int fd) const;
+    io_data_t *get_io_for_fd(int fd);
 
 };
 
 /**
    Remove the specified io redirection from the chain
 */
-void io_remove(io_chain_t &list, const shared_ptr<const io_data_t> &element);
+void io_remove(io_chain_t &list, const io_data_t *element);
+
+/** Make a copy of the specified chain of redirections. Uses operator new. */
+io_chain_t io_duplicate(const io_chain_t &chain);
 
 /** Return a shallow copy of the specified chain of redirections that contains only the applicable redirections. That is, if there's multiple redirections for the same fd, only the second one is included. */
 io_chain_t io_unique(const io_chain_t &chain);
@@ -147,14 +160,14 @@ void io_chain_destroy(io_chain_t &chain);
 /**
    Return the last io redirection in the chain for the specified file descriptor.
 */
-shared_ptr<const io_data_t> io_chain_get(const io_chain_t &src, int fd);
-shared_ptr<io_data_t> io_chain_get(io_chain_t &src, int fd);
+const io_data_t *io_chain_get(const io_chain_t &src, int fd);
+io_data_t *io_chain_get(io_chain_t &src, int fd);
 
 
 /**
    Free all resources used by a IO_BUFFER type io redirection.
 */
-void io_buffer_destroy(const shared_ptr<io_data_t> &io_buffer);
+void io_buffer_destroy(io_data_t *io_buffer);
 
 /**
    Create a IO_BUFFER type io redirection, complete with a pipe and a