From 98edf61de8f2c3d826604d57f7094adbd2a3b308 Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Thu, 5 Aug 2021 09:57:00 -0700
Subject: [PATCH] Add client/server fromEnv() without temporary Config on
 caller stack

---
 example/client.cpp     | 3 +--
 example/mailbox.cpp    | 3 +--
 example/rpc_client.cpp | 3 +--
 example/rpc_server.cpp | 3 +--
 example/simpleget.cpp  | 2 +-
 example/simplesrv.cpp  | 3 +--
 example/spam.cpp       | 3 +--
 example/ticker.cpp     | 3 +--
 src/client.cpp         | 5 +++++
 src/pvxs/client.h      | 8 ++++++++
 src/pvxs/server.h      | 8 ++++++++
 src/server.cpp         | 5 +++++
 test/mcat.cpp          | 3 +--
 tools/call.cpp         | 2 +-
 tools/get.cpp          | 2 +-
 tools/info.cpp         | 2 +-
 tools/monitor.cpp      | 2 +-
 tools/put.cpp          | 2 +-
 18 files changed, 40 insertions(+), 22 deletions(-)

diff --git a/example/client.cpp b/example/client.cpp
index 3949820..924b4ca 100644
--- a/example/client.cpp
+++ b/example/client.cpp
@@ -34,8 +34,7 @@ int main(int argc, char* argv[])
     logger_config_env();
 
     // Create a client context
-    client::Context ctxt(client::Config::fromEnv()
-                         .build());
+    auto ctxt(client::Context::fromEnv());
 
     // Fetch current value
     int32_t current;
diff --git a/example/mailbox.cpp b/example/mailbox.cpp
index 9d83399..9a104f4 100644
--- a/example/mailbox.cpp
+++ b/example/mailbox.cpp
@@ -91,8 +91,7 @@ int main(int argc, char* argv[])
 
     // Build server which will serve this PV
     // Configure using process environment.
-    server::Server serv = server::Config::fromEnv()
-            .build();
+    auto serv(server::Server::fromEnv());
 
     for(size_t i=0ul; i<pvs.size(); i++) {
         serv.addPV(argv[i+1], pvs[i]);
diff --git a/example/rpc_client.cpp b/example/rpc_client.cpp
index 650a113..fba4fde 100644
--- a/example/rpc_client.cpp
+++ b/example/rpc_client.cpp
@@ -34,8 +34,7 @@ int main(int argc, char* argv[])
     logger_config_env();
 
     // Create a client context
-    client::Context ctxt(client::Config::fromEnv()
-                         .build());
+    auto ctxt(client::Context::fromEnv());
 
     auto reply(ctxt.rpc(argv[1])
                    .arg("lhs", argv[2])
diff --git a/example/rpc_server.cpp b/example/rpc_server.cpp
index 79a58d9..a1d4204 100644
--- a/example/rpc_server.cpp
+++ b/example/rpc_server.cpp
@@ -71,8 +71,7 @@ int main(int argc, char* argv[])
 
     // Build server which will serve this PV
     // Configure using process environment.
-    server::Server serv = server::Config::fromEnv()
-            .build()
+    server::Server serv = server::Server::fromEnv()
             .addPV(argv[1], pv);
 
     // (optional) Print the configuration this server is using
diff --git a/example/simpleget.cpp b/example/simpleget.cpp
index 29c2654..19186e9 100644
--- a/example/simpleget.cpp
+++ b/example/simpleget.cpp
@@ -18,7 +18,7 @@ int main(int argc, char* argv[]) {
     logger_config_env();
 
     // Configure client using $EPICS_PVA_*
-    client::Context ctxt(client::Config::fromEnv().build());
+    auto ctxt(client::Context::fromEnv());
 
     // fetch PV "some:pv:name" and wait up to 5 seconds for a reply.
     // (throws an exception on error, including timeout)
diff --git a/example/simplesrv.cpp b/example/simplesrv.cpp
index 0b17b95..454a701 100644
--- a/example/simplesrv.cpp
+++ b/example/simplesrv.cpp
@@ -27,8 +27,7 @@ int main(int argc, char* argv[]) {
     server::SharedPV pv(server::SharedPV::buildMailbox());
     pv.open(initial);
 
-    server::Config::fromEnv()        // Configure a server using $EPICS_PVAS_* or $EPICS_PVA_*
-            .build()
+    server::Server::fromEnv()        // Configure a server using $EPICS_PVAS_* or $EPICS_PVA_*
             .addPV("my:pv:name", pv) // add (and name) one local PV
             .run();                  // run until SIGINT
 
diff --git a/example/spam.cpp b/example/spam.cpp
index 976674d..b895c94 100644
--- a/example/spam.cpp
+++ b/example/spam.cpp
@@ -102,8 +102,7 @@ int main(int argc, char* argv[])
 
     // Build server which will serve this PV
     // Configure using process environment.
-    server::Server serv = server::Config::fromEnv()
-            .build()
+    server::Server serv = server::Server::fromEnv()
             .addSource("spamsrc", src);
 
     // (optional) Print the configuration this server is using
diff --git a/example/ticker.cpp b/example/ticker.cpp
index 8c545a7..d5bb99d 100644
--- a/example/ticker.cpp
+++ b/example/ticker.cpp
@@ -73,8 +73,7 @@ int main(int argc, char* argv[])
 
     // Build server which will serve this PV
     // Configure using process environment.
-    server::Server serv = server::Config::fromEnv()
-            .build();
+    auto serv(server::Server::fromEnv());
 
     for(int i=1; i<argc; i++) {
         std::cout<<"PV "<<argv[i]<<"\n";
diff --git a/src/client.cpp b/src/client.cpp
index 52e9426..faeef08 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -353,6 +353,11 @@ Operation::~Operation() {}
 
 Subscription::~Subscription() {}
 
+Context Context::fromEnv()
+{
+    return Config::fromEnv().build();
+}
+
 Context::Context(const Config& conf)
     :pvt(std::make_shared<Pvt>(conf))
 {
diff --git a/src/pvxs/client.h b/src/pvxs/client.h
index c857153..7e9fc12 100644
--- a/src/pvxs/client.h
+++ b/src/pvxs/client.h
@@ -255,6 +255,14 @@ public:
     explicit Context(const Config &);
     ~Context();
 
+    /** Create new client context based on configuration from $EPICS_PVA* environment variables.
+     *
+     * Shorthand for @code Config::fromEnv().build() @endcode.
+     * @since UNRELEASED
+     */
+    static
+    Context fromEnv();
+
     //! effective config of running client
     const Config& config() const;
 
diff --git a/src/pvxs/server.h b/src/pvxs/server.h
index 668a0d9..d815f82 100644
--- a/src/pvxs/server.h
+++ b/src/pvxs/server.h
@@ -59,6 +59,14 @@ public:
     explicit Server(const Config&);
     ~Server();
 
+    /** Create new server based on configuration from $EPICS_PVA* environment variables.
+     *
+     * Shorthand for @code Config::fromEnv().build() @endcode.
+     * @since UNRELEASED
+     */
+    static
+    Server fromEnv();
+
     //! Begin serving.  Does not block.
     Server& start();
     //! Stop server
diff --git a/src/server.cpp b/src/server.cpp
index c13573d..8729b66 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -41,6 +41,11 @@ DEFINE_LOGGER(serversetup, "pvxs.server.setup");
 DEFINE_LOGGER(serverio, "pvxs.server.io");
 DEFINE_LOGGER(serversearch, "pvxs.server.search");
 
+Server Server::fromEnv()
+{
+    return Config::fromEnv().build();
+}
+
 Server::Server(const Config& conf)
 {
     /* Here be dragons.
diff --git a/test/mcat.cpp b/test/mcat.cpp
index 24b9ee1..38de630 100644
--- a/test/mcat.cpp
+++ b/test/mcat.cpp
@@ -152,8 +152,7 @@ int main(int argc, char* argv[])
     src->name = argv[optind];
     src->fname = argv[optind+1];
 
-    auto serv = server::Config::fromEnv()
-            .build()
+    auto serv = server::Server::fromEnv()
             .addSource("mcat", src);
 
     std::cout<<"Effective config\n"<<serv.config();
diff --git a/tools/call.cpp b/tools/call.cpp
index ce06e0b..27e61af 100644
--- a/tools/call.cpp
+++ b/tools/call.cpp
@@ -119,7 +119,7 @@ int main(int argc, char *argv[])
             query[pair.first] = pair.second;
         }
 
-        auto ctxt = client::Config::fromEnv().build();
+        auto ctxt(client::Context::fromEnv());
 
         if(verbose)
             std::cout<<"Effective config\n"<<ctxt.config();
diff --git a/tools/get.cpp b/tools/get.cpp
index 2e0817f..85d3fe0 100644
--- a/tools/get.cpp
+++ b/tools/get.cpp
@@ -96,7 +96,7 @@ int main(int argc, char *argv[])
             }
         }
 
-        auto ctxt = client::Config::fromEnv().build();
+        auto ctxt(client::Context::fromEnv());
 
         if(verbose)
             std::cout<<"Effective config\n"<<ctxt.config();
diff --git a/tools/info.cpp b/tools/info.cpp
index e4b95be..c511ce1 100644
--- a/tools/info.cpp
+++ b/tools/info.cpp
@@ -75,7 +75,7 @@ int main(int argc, char *argv[])
             }
         }
 
-        auto ctxt = client::Config::fromEnv().build();
+        auto ctxt(client::Context::fromEnv());
 
         if(verbose)
             std::cout<<"Effective config\n"<<ctxt.config();
diff --git a/tools/monitor.cpp b/tools/monitor.cpp
index ba2f773..a95e8ee 100644
--- a/tools/monitor.cpp
+++ b/tools/monitor.cpp
@@ -94,7 +94,7 @@ int main(int argc, char *argv[])
             }
         }
 
-        auto ctxt = client::Config::fromEnv().build();
+        auto ctxt(client::Context::fromEnv());
 
         if(verbose)
             std::cout<<"Effective config\n"<<ctxt.config();
diff --git a/tools/put.cpp b/tools/put.cpp
index faf48bb..5f1bff3 100644
--- a/tools/put.cpp
+++ b/tools/put.cpp
@@ -106,7 +106,7 @@ int main(int argc, char *argv[])
         }
 
 
-        auto ctxt = client::Config::fromEnv().build();
+        auto ctxt(client::Context::fromEnv());
 
         if(verbose)
             std::cout<<"Effective config\n"<<ctxt.config();