support change ownship for SelectiveChannel

Author: yanyuan06

src/brpc/selective_channel.cpp

@@ -41,10 +41,13 @@ typedef std::map<ChannelBase*, Socket*> ChannelToIdMap;
 class SubChannel : public SocketUser {
 public:
     ChannelBase* chan;
+    ChannelOwnership ownership;
 
     // internal channel is deleted after the fake Socket is SetFailed
     void BeforeRecycle(Socket*) {
-        delete chan;
+        if (ownership == OWNS_CHANNEL) {
+            delete chan;
+        }
         delete this;
     }
 
@@ -84,6 +87,7 @@ class ChannelBalancer : public SharedLoadBalancer {
     ~ChannelBalancer();
     int Init(const char* lb_name);
     int AddChannel(ChannelBase* sub_channel, const std::string& tag,
+                   ChannelOwnership ownership,
                    SelectiveChannel::ChannelHandle* handle);
     void RemoveAndDestroyChannel(const SelectiveChannel::ChannelHandle& handle);
     int SelectChannel(const LoadBalancer::SelectIn& in, SelectOut* out);
@@ -168,7 +172,9 @@ int ChannelBalancer::Init(const char* lb_name) {
     return SharedLoadBalancer::Init(lb_name);
 }
 
-int ChannelBalancer::AddChannel(ChannelBase* sub_channel, const std::string& tag,
+int ChannelBalancer::AddChannel(ChannelBase* sub_channel,
+                                const std::string& tag,
+                                ChannelOwnership ownership,
                                 SelectiveChannel::ChannelHandle* handle) {
     if (NULL == sub_channel) {
         LOG(ERROR) << "Parameter[sub_channel] is NULL";
@@ -185,6 +191,7 @@ int ChannelBalancer::AddChannel(ChannelBase* sub_channel, const std::string& tag
         return -1;
     }
     sub_chan->chan = sub_channel;
+    sub_chan->ownership = ownership;
     SocketId sock_id;
     SocketOptions options;
     options.user = sub_chan;
@@ -215,7 +222,7 @@ int ChannelBalancer::AddChannel(ChannelBase* sub_channel, const std::string& tag
         return -1;
     }
     // The health-check-related reference has been held on created.
-    _chan_map[sub_channel]= ptr.get();
+    _chan_map[sub_channel] = ptr.get();
     if (handle) {
         handle->id = sock_id;
         handle->tag = tag;
@@ -532,20 +539,15 @@ bool SelectiveChannel::initialized() const {
 }
 
 int SelectiveChannel::AddChannel(ChannelBase* sub_channel,
-                                 ChannelHandle* handle) {
-    return AddChannel(sub_channel, "", handle);
-}
-
-int SelectiveChannel::AddChannel(ChannelBase* sub_channel,
-                                 const std::string& tag,
+                                 const SubChannelOptions& option,
                                  ChannelHandle* handle) {
     schan::ChannelBalancer* lb =
         static_cast<schan::ChannelBalancer*>(_chan._lb.get());
     if (lb == NULL) {
         LOG(ERROR) << "You must call Init() to initialize a SelectiveChannel";
         return -1;
     }
-    return lb->AddChannel(sub_channel, tag, handle);
+    return lb->AddChannel(sub_channel, option.tag, option.ownership, handle);
 }
 
 void SelectiveChannel::RemoveAndDestroyChannel(const ChannelHandle& handle) {

src/brpc/selective_channel.h

@@ -56,6 +56,11 @@ class SelectiveChannel : public ChannelBase/*non-copyable*/ {
         std::string tag;
     };
 
+    struct SubChannelOptions {
+        std::string tag;
+        ChannelOwnership ownership;
+    };
+
     SelectiveChannel();
     ~SelectiveChannel();
 
@@ -69,8 +74,11 @@ class SelectiveChannel : public ChannelBase/*non-copyable*/ {
     // On success, handle is set with the key for removal.
     // NOTE: Different from pchan, schan can add channels at any time.
     // Returns 0 on success, -1 otherwise.
-    int AddChannel(ChannelBase* sub_channel, ChannelHandle* handle);
-    int AddChannel(ChannelBase* sub_channel, const std::string& tag, ChannelHandle* handle);
+    int AddChannel(ChannelBase* sub_channel, ChannelHandle* handle) {
+        return AddChannel(sub_channel, SubChannelOptions(), handle);
+    }
+    int AddChannel(ChannelBase* sub_channel, const SubChannelOptions& option,
+                   ChannelHandle* handle);
 
     // Remove and destroy the sub_channel associated with `handle'.
     void RemoveAndDestroyChannel(const ChannelHandle& handle);