disaggregate templates

src/client.cpp

@@ -1,9 +1,48 @@
 #include "MyService.proxy.h"
+#include "rpc/RpcChannel.h"
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
 #include <iostream>
+#include <string>
+
+class RpcChannelFifoClient : public RpcChannel {
+public:
+    RpcChannelFifoClient(const char* inPipe, const char* outPipe) {
+        fdOut = open(inPipe, O_WRONLY);
+        fdIn = open(outPipe, O_RDONLY);
+    }
+
+    void send(const std::string& data) override {
+        ::write(fdOut, data.c_str(), data.size());
+        ::write(fdOut, "\n", 1);
+    }
+
+    std::string receive() override {
+        char buf[4096];
+        int n = ::read(fdIn, buf, sizeof(buf) - 1);
+        if (n <= 0) {
+            return {};
+        }
+        buf[n] = 0;
+        return std::string(buf);
+    }
+
+private:
+    int fdIn{};
+    int fdOut{};
+};
 
 int main() {
-    MyServiceProxy proxy("/tmp/rpc_in", "/tmp/rpc_out");
+    mkfifo("/tmp/rpc_in", 0666);
+    mkfifo("/tmp/rpc_out", 0666);
+
+    RpcChannelFifoClient ch("/tmp/rpc_in", "/tmp/rpc_out");
+    MyServiceProxy proxy(ch);
 
     int r = proxy.add(7, 8);
     std::cout << "RESULT: " << r << std::endl;
 }
+

src/rpc/RpcChannel.h

@@ -0,0 +1,11 @@
+#pragma once
+#include <string>
+#include <vector>
+
+class RpcChannel {
+public:
+    virtual ~RpcChannel() = default;
+
+    virtual void send(const std::string& data) = 0;
+    virtual std::string receive() = 0;
+};

src/rpc/RpcChannelFifo.cpp

@@ -0,0 +1,35 @@
+#include "RpcChannel.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <string>
+
+class RpcChannelFifo : public RpcChannel {
+public:
+    RpcChannelFifo(const char* inPipe, const char* outPipe) {
+        fdOut = open(inPipe, O_WRONLY);
+        fdIn = open(outPipe, O_RDONLY);
+    }
+
+    void send(const std::string& data) override {
+        ::write(fdOut, data.c_str(), data.size());
+        ::write(fdOut, "\n", 1);
+    }
+
+    std::string receive() override {
+        char buf[4096];
+        int n = ::read(fdIn, buf, sizeof(buf) - 1);
+        if (n <= 0) {
+            return {};
+        }
+        buf[n] = 0;
+        return std::string(buf);
+    }
+
+private:
+    int fdIn{};
+    int fdOut{};
+};
+
+

src/rpc/RpcClient.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include "RpcChannel.h"
+#include "RpcSerializer.h"
+
+#include <sstream>
+#include <string>
+
+class RpcClient {
+public:
+    explicit RpcClient(RpcChannel& ch) : channel(ch) {}
+
+    template<typename Ret, typename... Args>
+    Ret call(const std::string& method, const Args&... args) {
+        std::ostringstream out;
+
+        // имя метода
+        RpcSerializer::write(out, method);
+
+        // аргументы
+        (RpcSerializer::write(out, args), ...);
+
+        // отправить
+        channel.send(out.str());
+
+        // получить ответ
+        std::string resp = channel.receive();
+        std::istringstream in(resp);
+
+        return RpcSerializer::read<Ret>(in);
+    }
+
+private:
+    RpcChannel& channel;
+};
+
+

src/rpc/RpcInvoker.h

@@ -0,0 +1,67 @@
+#pragma once
+
+#include "RpcSerializer.h"
+
+#include <functional>
+#include <sstream>
+#include <string>
+#include <tuple>
+#include <unordered_map>
+
+class RpcInvoker {
+public:
+    template<typename Obj, typename Ret, typename... Args>
+    void registerMethod(Obj* instance,
+                        const std::string& name,
+                        Ret (Obj::*method)(Args...)) {
+        handlers[name] =
+            [instance, method](const std::string& req) -> std::string {
+                std::istringstream in(req);
+
+                // пропустить имя метода
+                std::string skip;
+                in >> skip;
+
+                // читать аргументы и вызвать метод
+                return callMethod<Ret, Obj, Args...>(instance, method, in);
+            };
+    }
+
+    std::string dispatch(const std::string& request) {
+        std::istringstream in(request);
+        std::string method;
+        in >> method;
+
+        auto it = handlers.find(method);
+        if (it == handlers.end()) {
+            return "ERR";
+        }
+
+        return it->second(request);
+    }
+
+private:
+    template<typename Ret, typename Obj, typename... Args>
+    static std::string callMethod(Obj* obj,
+                                  Ret (Obj::*method)(Args...),
+                                  std::istringstream& in) {
+        auto tuple = readArgs<Args...>(in);
+        Ret result =
+            std::apply(method, std::tuple_cat(std::make_tuple(obj), tuple));
+
+        std::ostringstream out;
+        RpcSerializer::write(out, result);
+        return out.str();
+    }
+
+    template<typename... Args>
+    static std::tuple<Args...> readArgs(std::istringstream& in) {
+        return std::tuple<Args...>{RpcSerializer::read<Args>(in)...};
+    }
+
+    std::unordered_map<std::string,
+                       std::function<std::string(const std::string&)>>
+        handlers;
+};
+
+

src/rpc/RpcSerializer.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <sstream>
+#include <string>
+
+class RpcSerializer {
+public:
+    template<typename T>
+    static void write(std::ostringstream& out, const T& v) {
+        out << v << ' ';
+    }
+
+    template<typename T>
+    static T read(std::istringstream& in) {
+        T v;
+        in >> v;
+        return v;
+    }
+};
+
+

src/server.cpp

@@ -1,31 +1,58 @@
 #include "MyService.h"
 #include "MyService.skeleton.h"
 
+#include "rpc/RpcChannel.h"
+
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>
+
 #include <iostream>
+#include <string>
+
+class RpcChannelFifoServer : public RpcChannel {
+public:
+    RpcChannelFifoServer(const char* inPipe, const char* outPipe) {
+        fdIn = open(inPipe, O_RDONLY);
+        fdOut = open(outPipe, O_WRONLY);
+    }
+
+    void send(const std::string& data) override {
+        ::write(fdOut, data.c_str(), data.size());
+        ::write(fdOut, "\n", 1);
+    }
+
+    std::string receive() override {
+        char buf[4096];
+        int n = ::read(fdIn, buf, sizeof(buf) - 1);
+        if (n <= 0) {
+            return {};
+        }
+        buf[n] = 0;
+        return std::string(buf);
+    }
+
+private:
+    int fdIn{};
+    int fdOut{};
+};
 
 int main() {
     mkfifo("/tmp/rpc_in", 0666);
     mkfifo("/tmp/rpc_out", 0666);
 
-    int fdIn  = open("/tmp/rpc_in",  O_RDONLY);
-    int fdOut = open("/tmp/rpc_out", O_WRONLY);
+    RpcChannelFifoServer ch("/tmp/rpc_in", "/tmp/rpc_out");
 
     MyService realObj;
     MyServiceSkeleton skeleton(realObj);
 
-    char buf[256];
-
     while (true) {
-        int n = read(fdIn, buf, sizeof(buf)-1);
-        if (n <= 0) break;
-
-        buf[n] = 0;
-        std::string req(buf);
-        std::string resp = skeleton.handleRequest(req);
-
-        write(fdOut, resp.c_str(), resp.size());
+        std::string req = ch.receive();
+        if (req.empty()) {
+            break;
+        }
+        std::string resp = skeleton.dispatch(req);
+        ch.send(resp);
     }
 }
+

tools/templates/proxy.cpp.j2

@@ -1,38 +1,20 @@
 #include "{{ cls.name }}.proxy.h"
-#include <unistd.h>
-#include <fcntl.h>
-#include <sstream>
-#include <cstdlib>
-#include <cstring>
+#include "rpc/RpcClient.h"
 
-{{ cls.name }}Proxy::{{ cls.name }}Proxy(const char* pipeIn, const char* pipeOut) {
-    fdIn  = open(pipeIn,  O_WRONLY);
-    if (fdIn < 0) {
-        perror("open pipeIn");
-    }
-    fdOut = open(pipeOut, O_RDONLY);
-    if (fdOut < 0) {
-        perror("open pipeOut");
-    }
-}
+class {{ cls.name }}Proxy::Impl {
+public:
+    explicit Impl(RpcChannel& ch)
+        : client(ch) {}
+
+    RpcClient client;
+};
+
+{{ cls.name }}Proxy::{{ cls.name }}Proxy(RpcChannel& ch)
+    : impl(new Impl(ch)) {}
 
 {% for m in cls.methods %}
 {{ m.return_type }} {{ cls.name }}Proxy::{{ m.name }}({% for a in m.args %}{{ a.type }} {{ a.name }}{% if not loop.last %}, {% endif %}{% endfor %}) {
-    std::ostringstream out;
-    out << "{{ m.name }}";
-    {% for a in m.args %}
-    out << " " << {{ a.name }};
-    {% endfor %}
-    out << "\n";
-    std::string s = out.str();
-    write(fdIn, s.c_str(), (ssize_t)s.size());
-
-    char buf[256];
-    ssize_t n = read(fdOut, buf, sizeof(buf)-1);
-    if (n <= 0) {
-        return 0;
-    }
-    buf[n] = '\0';
-    return std::atoi(buf);
+    return impl->client.call<{{ m.return_type }}>("{{ cls.name }}.{{ m.name }}"{% for a in m.args %}, {{ a.name }}{% endfor %});
 }
 {% endfor %}
+

tools/templates/proxy.h.j2

@@ -1,15 +1,15 @@
 #pragma once
-#include <string>
-#include <memory>
-#include <cstdint>
+
+#include "rpc/RpcChannel.h"
 
 class {{ cls.name }}Proxy {
 public:
-    {{ cls.name }}Proxy(const char* pipeIn, const char* pipeOut);
+    explicit {{ cls.name }}Proxy(RpcChannel& ch);
     {% for m in cls.methods %}
     {{ m.return_type }} {{ m.name }}({% for a in m.args %}{{ a.type }} {{ a.name }}{% if not loop.last %}, {% endif %}{% endfor %});
     {% endfor %}
+
 private:
-    int fdIn;
-    int fdOut;
+    class Impl;
+    Impl* impl;
 };

tools/templates/skeleton.cpp.j2

@@ -1,19 +1,15 @@
 #include "{{ cls.name }}.skeleton.h"
-#include <sstream>
 
-{{ cls.name }}Skeleton::{{ cls.name }}Skeleton({{ cls.name }}& o) : obj(o) {}
+{{ cls.name }}Skeleton::{{ cls.name }}Skeleton({{ cls.name }}& obj)
+{
+{% for m in cls.methods %}
+    invoker.registerMethod(&obj,
+        "{{ cls.name }}.{{ m.name }}",
+        &{{ cls.name }}::{{ m.name }});
+{% endfor %}
+}
 
-std::string {{ cls.name }}Skeleton::handleRequest(const std::string& req) {
-    std::istringstream in(req);
-    std::string method;
-    in >> method;
-    {% for m in cls.methods %}
-    if (method == "{{ m.name }}") {
-        {% for a in m.args %}int {{ a.name }}; in >> {{ a.name }};
-        {% endfor %}
-        int res = obj.{{ m.name }}({% for a in m.args %}{{ a.name }}{% if not loop.last %}, {% endif %}{% endfor %});
-        return std::to_string(res);
-    }
-    {% endfor %}
-    return std::string("ERR");
+std::string {{ cls.name }}Skeleton::dispatch(const std::string& req) {
+    return invoker.dispatch(req);
 }
+

tools/templates/skeleton.h.j2

@@ -1,11 +1,16 @@
 #pragma once
+
 #include "{{ cls.name }}.h"
+#include "rpc/RpcInvoker.h"
+
 #include <string>
 
 class {{ cls.name }}Skeleton {
 public:
-    {{ cls.name }}Skeleton({{ cls.name }}& obj);
-    std::string handleRequest(const std::string& req);
+    explicit {{ cls.name }}Skeleton({{ cls.name }}& obj);
+
+    std::string dispatch(const std::string& req);
+
 private:
-    {{ cls.name }}& obj;
+    RpcInvoker invoker;
 };