Attachment 133104 Details for Bug 101895 – Implement dbus_clear_connection(), etc.

[patch] Implement dbus_clear_connection(), etc.

0001-Implement-dbus_clear_connection-etc.patch (text/plain), 8.78 KB, created by Simon McVittie on 2017-07-28 17:51:54 UTC

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Creator: Simon McVittie

Created: 2017-07-28 17:51:54 UTC

Size: 8.78 KB

patch

obsolete

>From 091ee331a249a562bd4f1327a53e546c22964dbf Mon Sep 17 00:00:00 2001
>From: Simon McVittie <smcv@collabora.com>
>Date: Fri, 21 Jul 2017 19:12:30 +0100
>Subject: [PATCH 1/2] Implement dbus_clear_connection(), etc.
>
>These are inspired by GLib's g_clear_pointer() and g_clear_object(),
>which in turn is descended from CPython's Py_CLEAR_OBJECT. They should
>make our code a lot less repetitive.
>
>Signed-off-by: Simon McVittie <smcv@collabora.com>
>
>---
>
>Be more careful with types and casts, to keep C++ compilers happy
>(see comment). This broke the build with mingw on Travis-CI, because
>we use a tiny amount of C++ on Windows to get code run at library init
>time in a non-horrific way.
>---
> dbus/dbus-address.h          | 19 +++++++++++++++++++
> dbus/dbus-connection.h       | 30 ++++++++++++++++++++++++++++++
> dbus/dbus-hash.h             |  6 ++++++
> dbus/dbus-macros.h           | 20 ++++++++++++++++++++
> dbus/dbus-message-internal.h |  6 ++++++
> dbus/dbus-message.h          | 19 +++++++++++++++++++
> dbus/dbus-pending-call.h     | 19 +++++++++++++++++++
> dbus/dbus-server.h           | 19 +++++++++++++++++++
> 8 files changed, 138 insertions(+)
>
>diff --git a/dbus/dbus-address.h b/dbus/dbus-address.h
>index 4d14fdf7..fefb320e 100644
>--- a/dbus/dbus-address.h
>+++ b/dbus/dbus-address.h
>@@ -59,6 +59,25 @@ DBUS_EXPORT
> char* dbus_address_unescape_value (const char *value,
>                                    DBusError  *error);
> 
>+/**
>+ * Clear a variable or struct member that contains an array of #DBusAddressEntry.
>+ * If it does not contain #NULL, the entries that were previously
>+ * there are freed with dbus_address_entries_free().
>+ *
>+ * This is similar to dbus_clear_connection(): see that function
>+ * for more details.
>+ *
>+ * @param pointer_to_entries A pointer to a variable or struct member.
>+ * pointer_to_entries must not be #NULL, but *pointer_to_entries
>+ * may be #NULL.
>+ */
>+static inline void
>+dbus_clear_address_entries (DBusAddressEntry ***pointer_to_entries)
>+{
>+  _dbus_clear_pointer_impl (DBusAddressEntry *, pointer_to_entries,
>+                            dbus_address_entries_free);
>+}
>+
> /** @} */
> 
> DBUS_END_DECLS
>diff --git a/dbus/dbus-connection.h b/dbus/dbus-connection.h
>index fe4d04ef..bed54242 100644
>--- a/dbus/dbus-connection.h
>+++ b/dbus/dbus-connection.h
>@@ -28,6 +28,7 @@
> #define DBUS_CONNECTION_H
> 
> #include <dbus/dbus-errors.h>
>+#include <dbus/dbus-macros.h>
> #include <dbus/dbus-memory.h>
> #include <dbus/dbus-message.h>
> #include <dbus/dbus-shared.h>
>@@ -438,6 +439,35 @@ DBUS_EXPORT
> dbus_bool_t dbus_connection_get_socket             (DBusConnection              *connection,
>                                                     int                         *fd);
> 
>+/**
>+ * Clear a variable or struct member that contains a #DBusConnection.
>+ * If it does not contain #NULL, the connection that was previously
>+ * there is unreferenced with dbus_connection_unref().
>+ *
>+ * For example, this function and the similar functions for
>+ * other reference-counted types can be used in code like this:
>+ *
>+ * @code
>+ * DBusConnection *conn = NULL;
>+ * struct { ...; DBusMessage *m; ... } *larger_structure = ...;
>+ *
>+ * ... code that might set conn or m to be non-NULL ...
>+ *
>+ * dbus_clear_connection (&conn);
>+ * dbus_clear_message (&larger_structure->m);
>+ * @endcode
>+ *
>+ * @param pointer_to_connection A pointer to a variable or struct member.
>+ * pointer_to_connection must not be #NULL, but *pointer_to_connection
>+ * may be #NULL.
>+ */
>+static inline void
>+dbus_clear_connection (DBusConnection **pointer_to_connection)
>+{
>+  _dbus_clear_pointer_impl (DBusConnection, pointer_to_connection,
>+                            dbus_connection_unref);
>+}
>+
> /** @} */
> 
> 
>diff --git a/dbus/dbus-hash.h b/dbus/dbus-hash.h
>index 93f717a9..fadab91f 100644
>--- a/dbus/dbus-hash.h
>+++ b/dbus/dbus-hash.h
>@@ -210,6 +210,12 @@ _dbus_hash_table_insert_pollable (DBusHashTable *table,
> #endif
> }
> 
>+static inline void
>+_dbus_clear_hash_table (DBusHashTable **table_p)
>+{
>+  _dbus_clear_pointer_impl (DBusHashTable, table_p, _dbus_hash_table_unref);
>+}
>+
> /** @} */
> 
> DBUS_END_DECLS
>diff --git a/dbus/dbus-macros.h b/dbus/dbus-macros.h
>index 0e784fe1..2c8956e3 100644
>--- a/dbus/dbus-macros.h
>+++ b/dbus/dbus-macros.h
>@@ -215,6 +215,26 @@
> #  define DBUS_PRIVATE_EXPORT /* no decoration */
> #endif
> 
>+/* Implementation for dbus_clear_message() etc. This is not API,
>+ * do not use it directly.
>+ *
>+ * We're using a specific type (T ** and T *) instead of void ** and
>+ * void * partly for type-safety, partly to be strict-aliasing-compliant,
>+ * and partly to keep C++ compilers happy. This code is inlined into
>+ * users of libdbus, so we can't rely on it having dbus' own compiler
>+ * settings. */
>+#define _dbus_clear_pointer_impl(T, pointer_to_pointer, destroy) \
>+  do { \
>+    T **_pp = (pointer_to_pointer); \
>+    T *_value = *_pp; \
>+    \
>+    *_pp = NULL; \
>+    \
>+    if (_value != NULL) \
>+      destroy (_value); \
>+  } while (0)
>+/* Not (destroy) (_value) in case destroy() is a function-like macro */
>+
> /** @} */
> 
> #endif /* DBUS_MACROS_H */
>diff --git a/dbus/dbus-message-internal.h b/dbus/dbus-message-internal.h
>index f8fe383f..38c79236 100644
>--- a/dbus/dbus-message-internal.h
>+++ b/dbus/dbus-message-internal.h
>@@ -135,6 +135,12 @@ const DBusString  *_dbus_variant_peek                            (DBusVariant *s
> DBUS_PRIVATE_EXPORT
> const char        *_dbus_variant_get_signature                   (DBusVariant *self);
> 
>+static inline void
>+_dbus_clear_variant (DBusVariant **variant_p)
>+{
>+  _dbus_clear_pointer_impl (DBusVariant, variant_p, _dbus_variant_free);
>+}
>+
> typedef struct DBusInitialFDs DBusInitialFDs;
> DBusInitialFDs *_dbus_check_fdleaks_enter (void);
> void            _dbus_check_fdleaks_leave (DBusInitialFDs *fds);
>diff --git a/dbus/dbus-message.h b/dbus/dbus-message.h
>index 9e7ae7fe..8a9d57a0 100644
>--- a/dbus/dbus-message.h
>+++ b/dbus/dbus-message.h
>@@ -351,6 +351,25 @@ DBUS_EXPORT
> dbus_bool_t dbus_message_get_allow_interactive_authorization (
>     DBusMessage *message);
> 
>+/**
>+ * Clear a variable or struct member that contains a #DBusMessage.
>+ * If it does not contain #NULL, the message that was previously
>+ * there is unreferenced with dbus_message_unref().
>+ *
>+ * This is very similar to dbus_clear_connection(): see that function
>+ * for more details.
>+ *
>+ * @param pointer_to_message A pointer to a variable or struct member.
>+ * pointer_to_message must not be #NULL, but *pointer_to_message
>+ * may be #NULL.
>+ */
>+static inline void
>+dbus_clear_message (DBusMessage **pointer_to_message)
>+{
>+  _dbus_clear_pointer_impl (DBusMessage, pointer_to_message,
>+                            dbus_message_unref);
>+}
>+
> /** @} */
> 
> DBUS_END_DECLS
>diff --git a/dbus/dbus-pending-call.h b/dbus/dbus-pending-call.h
>index 8a37ec0a..5593397a 100644
>--- a/dbus/dbus-pending-call.h
>+++ b/dbus/dbus-pending-call.h
>@@ -72,6 +72,25 @@ DBUS_EXPORT
> void*       dbus_pending_call_get_data           (DBusPendingCall  *pending,
>                                                   dbus_int32_t      slot);
> 
>+/**
>+ * Clear a variable or struct member that contains a #DBusPendingCall.
>+ * If it does not contain #NULL, the pending call that was previously
>+ * there is unreferenced with dbus_pending_call_unref().
>+ *
>+ * This is very similar to dbus_clear_connection(): see that function
>+ * for more details.
>+ *
>+ * @param pointer_to_pending_call A pointer to a variable or struct member.
>+ * pointer_to_pending_call must not be #NULL, but *pointer_to_pending_call
>+ * may be #NULL.
>+ */
>+static inline void
>+dbus_clear_pending_call (DBusPendingCall **pointer_to_pending_call)
>+{
>+  _dbus_clear_pointer_impl (DBusPendingCall, pointer_to_pending_call,
>+                            dbus_pending_call_unref);
>+}
>+
> /** @} */
> 
> DBUS_END_DECLS
>diff --git a/dbus/dbus-server.h b/dbus/dbus-server.h
>index bdbefa0f..7d8f04e4 100644
>--- a/dbus/dbus-server.h
>+++ b/dbus/dbus-server.h
>@@ -28,6 +28,7 @@
> #define DBUS_SERVER_H
> 
> #include <dbus/dbus-errors.h>
>+#include <dbus/dbus-macros.h>
> #include <dbus/dbus-message.h>
> #include <dbus/dbus-connection.h>
> #include <dbus/dbus-protocol.h>
>@@ -99,6 +100,24 @@ DBUS_EXPORT
> void*       dbus_server_get_data           (DBusServer       *server,
>                                             int               slot);
> 
>+/**
>+ * Clear a variable or struct member that contains a #DBusServer.
>+ * If it does not contain #NULL, the server that was previously
>+ * there is unreferenced with dbus_server_unref().
>+ *
>+ * This is very similar to dbus_clear_connection(): see that function
>+ * for more details.
>+ *
>+ * @param pointer_to_server A pointer to a variable or struct member.
>+ * pointer_to_server must not be #NULL, but *pointer_to_server
>+ * may be #NULL.
>+ */
>+static inline void
>+dbus_clear_server (DBusServer **pointer_to_server)
>+{
>+  _dbus_clear_pointer_impl (DBusServer, pointer_to_server, dbus_server_unref);
>+}
>+
> /** @} */
> 
> DBUS_END_DECLS
>-- 
>2.13.3
>

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