Introspect can error

2019-11-19 15:51:36 -08:00
parent f063bd26f5
commit 9ceab63d02
7 changed files with 261 additions and 52 deletions
@@ -0,0 +1,119 @@
+/**
+ * Copyright - See the COPYRIGHT that is included with this distribution.
+ * pvxs is distributed subject to a Software License Agreement found
+ * in file LICENSE that is included with this distribution.
+ */
+
+#include <cassert>
+
+#include <pvxs/log.h>
+#include "serverconn.h"
+
+namespace pvxs { namespace impl {
+DEFINE_LOGGER(connsetup, "tcp.setup");
+
+namespace {
+struct ServerIntrospect : public ServerOp
+{
+    ServerIntrospect(const std::shared_ptr<ServerChan>& chan, uint32_t ioid)
+        :ServerOp(chan, ioid)
+    {}
+    virtual ~ServerIntrospect() {}
+};
+
+struct ServerIntrospectControl : public server::Introspect
+{
+    ServerIntrospectControl(ServerConn* conn,
+                            const std::weak_ptr<server::Server::Pvt>& server,
+                            const std::string& name,
+                            const std::weak_ptr<ServerIntrospect>& op)
+        :server::Introspect(conn->peerName, conn->iface->name, name)
+        ,server(server)
+        ,op(op)
+    {}
+    virtual ~ServerIntrospectControl() {
+        error("Implict Cancel");
+    }
+
+    virtual void error(const std::string &msg) override final
+    {
+        Status sts{Status::Error, msg};
+        auto serv = server.lock();
+        if(!serv)
+            return; // soft fail if already completed, cancelled, disconnected, ....
+
+        serv->acceptor_loop.call([this, &sts](){
+            auto oper = op.lock();
+            if(!oper || oper->state != ServerOp::Executing)
+                return;
+            auto chan = oper->chan.lock();
+            if(!chan)
+                return;
+            auto conn = chan->conn.lock();
+            if(!conn || !conn->bev)
+                return;
+
+            const bool be = EPICS_BYTE_ORDER==EPICS_ENDIAN_BIG;
+            {
+                (void)evbuffer_drain(conn->txBody.get(), evbuffer_get_length(conn->txBody.get()));
+
+                EvOutBuf R(be, conn->txBody.get());
+                to_wire(R, uint32_t(oper->ioid));
+                to_wire(R, sts);
+                // would be FieldDesc payload if Ok or Warn
+            }
+
+            auto tx = bufferevent_get_output(conn->bev.get());
+            to_evbuf(tx, Header{pva_app_msg::Introspect,
+                                pva_flags::Server,
+                                uint32_t(evbuffer_get_length(conn->txBody.get()))},
+                     be);
+            auto err = evbuffer_add_buffer(tx, conn->txBody.get());
+            assert(!err);
+
+            oper->state = ServerOp::Dead;
+            conn->opByIOID.erase(oper->ioid);
+            chan->opByIOID.erase(oper->ioid);
+        });
+    }
+
+    const std::weak_ptr<server::Server::Pvt> server;
+    const std::weak_ptr<ServerIntrospect> op;
+};
+} // namespace
+
+void ServerConn::handle_Introspect()
+{
+    // aka. GetField
+
+    EvInBuf M(peerBE, segBuf.get(), 16);
+
+    uint32_t sid = -1, ioid = -1;
+    std::string subfield;
+
+    from_wire(M, sid);
+    from_wire(M, ioid);
+    from_wire(M, subfield);
+    if(!M.good())
+        throw std::runtime_error("Error decoding Introspect");
+
+    auto& chan = lookupSID(sid);
+
+    if(opByIOID.find(ioid)!=opByIOID.end()) {
+        log_printf(connsetup, PLVL_ERR, "Client %s reuses existing ioid %d\n", peerName.c_str(), unsigned(ioid));
+        return;
+    }
+
+    std::shared_ptr<ServerIntrospect> op(new ServerIntrospect(chan, ioid));
+    std::unique_ptr<ServerIntrospectControl> ctrl(new ServerIntrospectControl(this, iface->server->internal_self, chan->name, op));
+
+    op->state = ServerOp::Executing; // this is a one-shot operation
+
+    opByIOID[ioid] = op;
+    chan->opByIOID[ioid] = op;
+
+    if(chan->handler)
+        chan->handler->onIntrospect(std::move(ctrl));
+}
+
+}} // namespace pvxs::impl