[tor-commits] [tor/master] Declare the subsystem structure.

[nickm at torproject.org]

commit 0ce1f2d46646fd73abee56888650288055f16a53
Author: Nick Mathewson <nickm at torproject.org>
Date:   Thu Nov 1 08:18:29 2018 -0400

    Declare the subsystem structure.
---
 src/include.am              |  1 +
 src/lib/subsys/.may_include |  1 +
 src/lib/subsys/include.am   |  3 +++
 src/lib/subsys/subsys.h     | 63 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 68 insertions(+)

diff --git a/src/include.am b/src/include.am
index d2f83da81..247b0db8d 100644
--- a/src/include.am
+++ b/src/include.am
@@ -25,6 +25,7 @@ include src/lib/osinfo/include.am
 include src/lib/process/include.am
 include src/lib/sandbox/include.am
 include src/lib/string/include.am
+include src/lib/subsys/include.am
 include src/lib/smartlist_core/include.am
 include src/lib/term/include.am
 include src/lib/testsupport/include.am
diff --git a/src/lib/subsys/.may_include b/src/lib/subsys/.may_include
new file mode 100644
index 000000000..2b06e8519
--- /dev/null
+++ b/src/lib/subsys/.may_include
@@ -0,0 +1 @@
+orconfig.h
diff --git a/src/lib/subsys/include.am b/src/lib/subsys/include.am
new file mode 100644
index 000000000..4741126b1
--- /dev/null
+++ b/src/lib/subsys/include.am
@@ -0,0 +1,3 @@
+
+noinst_HEADERS += \
+	src/lib/subsys/subsys.h
diff --git a/src/lib/subsys/subsys.h b/src/lib/subsys/subsys.h
new file mode 100644
index 000000000..7e4fe5363
--- /dev/null
+++ b/src/lib/subsys/subsys.h
@@ -0,0 +1,63 @@
+/* Copyright (c) 2003-2004, Roger Dingledine
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2018, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#ifndef TOR_SUBSYS_T
+#define TOR_SUBSYS_T
+
+#include <stdbool.h>
+
+struct dispatch_connector_t;
+
+/**
+ * A subsystem is a part of Tor that is initialized, shut down, configured,
+ * and connected to other parts of Tor.
+ *
+ * Subsystems
+ **/
+typedef struct subsys_fns_t {
+  /**
+   * The name of this subsystem.  It should be a programmer-readable
+   * identifier.
+   **/
+  const char *name;
+
+  /**
+   * Whether this subsystem is supported -- that is, whether it is compiled
+   * into Tor.  For most subsystems, this should be true.
+   **/
+  bool supported;
+
+  /**
+   * The 'initialization level' for the subsystem.  It should run from -100
+   * through +100.  The subsystems are initialized from lowest level to
+   * highest, and shut down from highest level to lowest.
+   **/
+  int level;
+
+  /**
+   * Initialize any global components of this subsystem.
+   *
+   * This function MAY rely on any lower-level subsystem being initialized.
+   *
+   * This function MUST NOT rely on any runtime configuration information;
+   * it is only for global state or pre-configuration state.
+   **/
+  int (*initialize)(void);
+
+  /**
+   * Connect a subsystem to the message dispatch system.
+   **/
+  int (*add_pubsub)(struct dispatch_connector_t *);
+
+  /**
+   * Free all resources held by this subsystem.
+   *
+   * This function is not allowed to fail.
+   **/
+  void (*shutdown)(void);
+
+} subsys_fns_t;
+
+#endif