[PATCH v2 13/21] migration: introduce new constructors for QEMUFile

[Daniel P . Berrangé]

Prepare for the elimination of QEMUFileOps by introducing a pair of new
constructors. This lets us distinguish between an input and output file
object explicitly rather than via the existance of specific callbacks.

Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
---
 migration/qemu-file-channel.c |  4 ++--
 migration/qemu-file.c         | 18 ++++++++++++++++--
 migration/qemu-file.h         |  3 ++-
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/migration/qemu-file-channel.c b/migration/qemu-file-channel.c
index ce8eced417..5cb8ac93c0 100644
--- a/migration/qemu-file-channel.c
+++ b/migration/qemu-file-channel.c
@@ -184,11 +184,11 @@ static const QEMUFileOps channel_output_ops = {
 QEMUFile *qemu_fopen_channel_input(QIOChannel *ioc)
 {
     object_ref(OBJECT(ioc));
-    return qemu_fopen_ops(ioc, &channel_input_ops);
+    return qemu_file_new_input(ioc, &channel_input_ops);
 }
 
 QEMUFile *qemu_fopen_channel_output(QIOChannel *ioc)
 {
     object_ref(OBJECT(ioc));
-    return qemu_fopen_ops(ioc, &channel_output_ops);
+    return qemu_file_new_output(ioc, &channel_output_ops);
 }
diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index ce48d7a5d8..c181686e41 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -38,6 +38,7 @@ struct QEMUFile {
     const QEMUFileOps *ops;
     const QEMUFileHooks *hooks;
     QIOChannel *ioc;
+    bool is_writable;
 
     /*
      * Maximum amount of data in bytes to transfer during one
@@ -111,7 +112,9 @@ bool qemu_file_mode_is_not_valid(const char *mode)
     return false;
 }
 
-QEMUFile *qemu_fopen_ops(QIOChannel *ioc, const QEMUFileOps *ops)
+static QEMUFile *qemu_file_new_impl(QIOChannel *ioc,
+                                    const QEMUFileOps *ops,
+                                    bool is_writable)
 {
     QEMUFile *f;
 
@@ -119,10 +122,21 @@ QEMUFile *qemu_fopen_ops(QIOChannel *ioc, const 
QEMUFileOps *ops)
 
     f->ioc = ioc;
     f->ops = ops;
+    f->is_writable = is_writable;
 
     return f;
 }
 
+QEMUFile *qemu_file_new_output(QIOChannel *ioc, const QEMUFileOps *ops)
+{
+    return qemu_file_new_impl(ioc, ops, true);
+}
+
+QEMUFile *qemu_file_new_input(QIOChannel *ioc, const QEMUFileOps *ops)
+{
+    return qemu_file_new_impl(ioc, ops, false);
+}
+
 
 void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks)
 {
@@ -181,7 +195,7 @@ void qemu_file_set_error(QEMUFile *f, int ret)
 
 bool qemu_file_is_writable(QEMUFile *f)
 {
-    return f->ops->writev_buffer;
+    return f->is_writable;
 }
 
 static void qemu_iovec_release_ram(QEMUFile *f)
diff --git a/migration/qemu-file.h b/migration/qemu-file.h
index 3a1ecc0e34..3c93a27978 100644
--- a/migration/qemu-file.h
+++ b/migration/qemu-file.h
@@ -118,7 +118,8 @@ typedef struct QEMUFileHooks {
     QEMURamSaveFunc *save_page;
 } QEMUFileHooks;
 
-QEMUFile *qemu_fopen_ops(QIOChannel *ioc, const QEMUFileOps *ops);
+QEMUFile *qemu_file_new_input(QIOChannel *ioc, const QEMUFileOps *ops);
+QEMUFile *qemu_file_new_output(QIOChannel *ioc, const QEMUFileOps *ops);
 void qemu_file_set_hooks(QEMUFile *f, const QEMUFileHooks *hooks);
 int qemu_get_fd(QEMUFile *f);
 int qemu_fclose(QEMUFile *f);
-- 
2.36.1