Shared subchannel sketch

3 files changed, 195 insertions, 0 deletions

diff --git a/src/core/client_config/subchannel.c b/src/core/client_config/subchannel.c
index 2992da8b79..9f287c4b03 100644
--- a/src/core/client_config/subchannel.c
+++ b/src/core/client_config/subchannel.c
@@ -36,6 +36,7 @@
 #include <string.h>
 
 #include <grpc/support/alloc.h>
+#include <grpc/support/avl.h>
 
 #include "src/core/channel/channel_args.h"
 #include "src/core/channel/client_channel.h"
diff --git a/src/core/client_config/subchannel_index.c b/src/core/client_config/subchannel_index.c
new file mode 100644
index 0000000000..ffe6c1fe93
--- /dev/null
+++ b/src/core/client_config/subchannel_index.c
@@ -0,0 +1,155 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+/* a map of subchannel_key --> subchannel, used for detecting connections
+   to the same destination in order to share them */
+static gpr_avl g_subchannel_index;
+
+static gpr_mu g_mu;
+
+struct subchannel_key {
+  size_t addr_len;
+  struct sockaddr *addr;
+  grpc_channel_args *normalized_args;
+};
+
+GPR_TLS_DECL(subchannel_index_exec_ctx);
+
+static subchannel_key *subchannel_key_create(struct sockaddr *sockaddr, size_t addr_len, grpc_channel_args *args) {
+  subchannel_key *k = gpr_malloc(sizeof(*k));
+  k->addr_len = addr_len;
+  k->addr = gpr_malloc(addr_len);
+  memcpy(k->addr, addr, addr_len);
+  k->normalized_args = grpc_channel_args_normalize(args);
+  return k;
+}
+
+static subchannel_key *subchannel_key_copy(subchannel_key *k) {
+  subchannel_key *k = gpr_malloc(sizeof(*k));
+  k->addr_len = addr_len;
+  k->addr = gpr_malloc(addr_len);
+  memcpy(k->addr, addr, addr_len);
+  k->normalized_args = grpc_channel_args_copy(args);
+  return k;
+}
+
+static int subchannel_key_compare(subchannel_key *a, subchannel_key *b) {
+  int c = GPR_ICMP(a->addr_len, b->addr_len);
+  if (c != 0) return c;
+  c = memcmp(a->addr, b->addr, a->addr_len);
+  if (c != 0) return c;
+  return grpc_channel_args_compare(a->normalized_args, b->normalized_args);
+}
+
+static void subchannel_key_destroy(subchannel_key *k) {
+  gpr_free(k->addr);
+  grpc_channel_args_destroy(k->normalized_args);
+  gpr_free(k);
+}
+
+static void sck_avl_destroy(void *p) {
+  subchannel_key_destroy(p);
+}
+
+static void *sck_avl_copy(void *p) {
+  return subchannel_key_copy(p);
+}
+
+static void *sck_avl_compare(void *a, void *b) {
+  return subchannel_key_compare(a, b);
+}
+
+static void scv_avl_destroy(void *p) {
+  GRPC_SUBCHANNEL_UNREF(exec_ctx, p, "subchannel_index");
+}
+
+static void *scv_avl_copy(void *p) { 
+  GRPC_SUBCHANNEL_REF(p, "subchannel_index");
+  return p; 
+}
+
+static const gpr_avl_vtable subchannel_avl_vtable = {
+  .destroy_key = sck_avl_destroy,
+  .copy_key = sck_avl_copy,
+  .compare_keys = sck_avl_compare,
+  .destroy_value = scv_avl_destroy,
+  .copy_value = scv_avl_copy  
+};
+
+grpc_subchannel *grpc_subchannel_index_find(
+		grpc_exec_ctx *ctx,
+		grpc_connector *connector,
+		grpc_subchannel_args *args) {
+	gpr_mu_lock(&g_mu);
+	gpr_avl index = gpr_avl_ref(g_subchannel_index);
+	gpr_mu_unlock(&g_mu);
+
+	subchannel_key *key = subchannel_key_create(connector, args);
+	grpc_subchannel *c = grpc_subchannel_ref(gpr_avl_get(index, key));
+	subchannel_key_destroy(key);
+	gpr_avl_unref(index);
+
+	return c;
+}
+
+grpc_subchannel *grpc_subchannel_index_register(
+	  grpc_exec_ctx *ctx,
+		grpc_connector *connector, 
+		grpc_subchannel_args *args, 
+		grpc_subchannel *constructed) {
+	subchannel_key *key = subchannel_key_create(connector, args);
+	grpc_subchannel *c = NULL;
+
+	while (c == NULL) {
+		gpr_mu_lock(&g_mu);
+		gpr_avl index = gpr_avl_ref(g_subchannel_index);
+		gpr_mu_unlock(&g_mu);
+
+		c = gpr_avl_get(index, key);
+		if (c != NULL) {
+			GRPC_SUBCHANNEL_UNREF(constructed);
+		} else {
+			gpr_avl updated = gpr_avl_add(index, key, constructed);
+
+			gpr_mu_lock(&g_mu);
+			if (index.root == g_subchannel_index.root) {
+				GPR_SWAP(index, g_subchannel_index);
+				c = constructed;
+			}
+			gpr_mu_unlock(&g_mu);
+		}
+		gpr_avl_unref(index);
+	}
+
+	return c;
+}
diff --git a/src/core/client_config/subchannel_index.h b/src/core/client_config/subchannel_index.h
new file mode 100644
index 0000000000..d501e121f1
--- /dev/null
+++ b/src/core/client_config/subchannel_index.h
@@ -0,0 +1,39 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_INDEX_H
+#define GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_INDEX_H
+
+
+
+#endif /* GRPC_INTERNAL_CORE_CLIENT_CONFIG_SUBCHANNEL_INDEX_H */