Merge pull request #552 from crypto-chassis/example-how-to-reduce-build-time

how to reduce build time

Author: cryptochassis

README.md

@@ -45,6 +45,7 @@
       - [Use multiple sessions](#use-multiple-sessions)
       - [Override exchange urls](#override-exchange-urls)
       - [Connect to a proxy](#connect-to-a-proxy)
+      - [Reduce build time](#reduce-build-time)
   - [Performance Tuning](#performance-tuning)
   - [Known Issues and Workarounds](#known-issues-and-workarounds)
 
@@ -1081,6 +1082,8 @@ Instantiate `Subscription` with the desired `proxyUrl`.
 Subscription subscription("okx", "BTC-USDT", "MARKET_DEPTH", "", "", {}, "172.30.0.146:9000");
 ```
 
+#### Reduce build time
+The Pimpl (Pointer to Implementation) idiom in C++ can significantly reduce build time. This reduction is achieved by minimizing compilation dependencies and isolating implementation details. See [this example](example/src/reduce_build_time).
 
 ## Performance Tuning
 * Turn on compiler optimization flags (e.g. `cmake -DCMAKE_BUILD_TYPE=Release ...`).

example/CMakeLists.txt

@@ -87,3 +87,4 @@ add_subdirectory(src/override_exchange_url_at_runtime)
 add_subdirectory(src/test_order_latency)
 add_subdirectory(src/test_cpu_usage)
 add_subdirectory(src/use_multiple_sessions)
+add_subdirectory(src/reduce_build_time)

example/src/reduce_build_time/CMakeLists.txt

@@ -0,0 +1,6 @@
+set(NAME reduce_build_time)
+project(${NAME})
+add_compile_definitions(CCAPI_ENABLE_SERVICE_MARKET_DATA)
+add_compile_definitions(CCAPI_ENABLE_EXCHANGE_OKX)
+add_executable(${NAME} main.cpp my_session.cpp)
+add_dependencies(${NAME} boost rapidjson)

example/src/reduce_build_time/main.cpp

@@ -0,0 +1,38 @@
+#include "ccapi_cpp/ccapi_event_handler.h"
+#include "my_session.h"
+
+namespace ccapi {
+
+Logger* Logger::logger = nullptr;  // This line is needed.
+
+class MyEventHandler : public EventHandler {
+ public:
+  void processEvent(const Event& event, Session*) override { std::cout << "Received an event:\n" + event.toPrettyString(2, 2) << std::endl; }
+
+  void setMySessionPtr(MySession* mySessionPtr) { this->mySessionPtr = mySessionPtr; }
+
+ private:
+  MySession* mySessionPtr{nullptr};
+};
+
+} /* namespace ccapi */
+
+using ::ccapi::MyEventHandler;
+using ::ccapi::MySession;
+using ::ccapi::SessionConfigs;
+using ::ccapi::SessionOptions;
+using ::ccapi::Subscription;
+
+int main(int argc, char** argv) {
+  SessionOptions sessionOptions;
+  SessionConfigs sessionConfigs;
+  MyEventHandler eventHandler;
+  MySession mySession(sessionOptions, sessionConfigs, &eventHandler);
+  eventHandler.setMySessionPtr(&mySession);
+  Subscription subscription("okx", "BTC-USDT", "MARKET_DEPTH");
+  mySession.subscribe(subscription);
+  std::this_thread::sleep_for(std::chrono::seconds(10));
+  mySession.stop();
+  std::cout << "Bye" << std::endl;
+  return EXIT_SUCCESS;
+}

example/src/reduce_build_time/my_session.cpp

@@ -0,0 +1,14 @@
+#include "my_session.h"
+
+#include "ccapi_cpp/ccapi_session.h"
+
+namespace ccapi {
+
+MySession::MySession(const SessionOptions& sessionOptions, const SessionConfigs& sessionConfigs, EventHandler* eventHandler)
+    : ccapiSessionPtr(new Session(sessionOptions, sessionConfigs, eventHandler)) {}
+
+void MySession::subscribe(Subscription& subscription) { this->ccapiSessionPtr->subscribe(subscription); }
+
+void MySession::stop() { this->ccapiSessionPtr->stop(); }
+
+}  // namespace ccapi

example/src/reduce_build_time/my_session.h

@@ -0,0 +1,25 @@
+#ifndef EXAMPLE_SRC_REDUCE_BUILD_TIME_MY_SESSION_H_
+#define EXAMPLE_SRC_REDUCE_BUILD_TIME_MY_SESSION_H_
+
+#include "ccapi_cpp/ccapi_session_configs.h"
+#include "ccapi_cpp/ccapi_session_options.h"
+#include "ccapi_cpp/ccapi_subscription.h"
+
+namespace ccapi {
+
+class EventHandler;
+class Session;  // forward declaration instead of including full header!
+
+class MySession {
+ public:
+  explicit MySession(const SessionOptions& sessionOptions, const SessionConfigs& sessionConfigs, EventHandler* eventHandler);
+  void subscribe(Subscription& subscription);
+  void stop();
+
+ private:
+  Session* ccapiSessionPtr{nullptr};
+};
+
+}  // namespace ccapi
+
+#endif  // EXAMPLE_SRC_REDUCE_BUILD_TIME_MY_SESSION_H_

include/ccapi_cpp/ccapi_inflate_stream.h

@@ -58,14 +58,14 @@ class InflateStream {
     return boost::system::error_code();
   }
 
-  boost::system::error_code decompress(uint8_t const *buf, size_t len, std::string &out) {
+  boost::system::error_code decompress(uint8_t const* buf, size_t len, std::string& out) {
     if (!this->initialized) {
       CCAPI_LOGGER_ERROR("decompress error");
       return boost::system::error_code();
     }
 
     this->istate.avail_in = len;
-    this->istate.next_in = const_cast<unsigned char *>(buf);
+    this->istate.next_in = const_cast<unsigned char*>(buf);
     do {
       this->istate.avail_out = this->decompressBufferSize;
       this->istate.next_out = this->buffer.get();
@@ -74,7 +74,7 @@ class InflateStream {
         CCAPI_LOGGER_ERROR("decompress error");
         return boost::system::error_code();
       }
-      out.append(reinterpret_cast<char *>(this->buffer.get()), this->decompressBufferSize - this->istate.avail_out);
+      out.append(reinterpret_cast<char*>(this->buffer.get()), this->decompressBufferSize - this->istate.avail_out);
     } while (this->istate.avail_out == 0);
     return boost::system::error_code();
   }

include/ccapi_cpp/ccapi_url.h

@@ -31,7 +31,7 @@ class Url {
     return output;
   }
 
-  static std::string urlEncode(const std::string &value) {
+  static std::string urlEncode(const std::string& value) {
     std::ostringstream escaped;
     escaped.fill('0');
     escaped << std::hex;
@@ -50,7 +50,7 @@ class Url {
     return escaped.str();
   }
 
-  static std::string urlDecode(const std::string &value) {
+  static std::string urlDecode(const std::string& value) {
     std::string ret;
     char ch;
     int i, ii;
@@ -67,18 +67,18 @@ class Url {
     return (ret);
   }
 
-  static std::map<std::string, std::string> convertQueryStringToMap(const std::string &input) {
+  static std::map<std::string, std::string> convertQueryStringToMap(const std::string& input) {
     std::map<std::string, std::string> output;
-    for (const auto &x : UtilString::split(input, "&")) {
+    for (const auto& x : UtilString::split(input, "&")) {
       auto y = UtilString::split(x, "=");
       output.insert(std::make_pair(y.at(0), Url::urlDecode(y.at(1))));
     }
     return output;
   }
 
-  static std::string convertMapToQueryString(const std::map<std::string, std::string> &input) {
+  static std::string convertMapToQueryString(const std::map<std::string, std::string>& input) {
     std::string output;
-    for (const auto &x : input) {
+    for (const auto& x : input) {
       output += x.first;
       output += "=";
       output += x.second;
@@ -90,10 +90,10 @@ class Url {
     return output;
   }
 
-  static std::string convertMapToFormUrlEncoded(const std::map<std::string, std::string> &input) {
+  static std::string convertMapToFormUrlEncoded(const std::map<std::string, std::string>& input) {
     std::string output;
     int i = 0;
-    for (const auto &x : input) {
+    for (const auto& x : input) {
       output += Url::urlEncode(x.first);
       output += "=";
       output += Url::urlEncode(x.second);
@@ -104,9 +104,9 @@ class Url {
     return output;
   }
 
-  static std::map<std::string, std::string> convertFormUrlEncodedToMap(const std::string &input) {
+  static std::map<std::string, std::string> convertFormUrlEncodedToMap(const std::string& input) {
     std::map<std::string, std::string> output;
-    for (const auto &x : UtilString::split(input, "&")) {
+    for (const auto& x : UtilString::split(input, "&")) {
       auto y = UtilString::split(x, "=");
       output.insert(std::make_pair(Url::urlDecode(y.at(0)), Url::urlDecode(y.at(1))));
     }

test/test_build/test.cpp

@@ -1,7 +1,7 @@
 #include "ccapi_cpp/ccapi_session.h"
 using ::ccapi::Session;
 
-int main(int argc, char **argv) {
+int main(int argc, char** argv) {
   Session session;
   return EXIT_SUCCESS;
 }