From 951448f6b2cd0effb4b45a02c02908b75daec3d7 Mon Sep 17 00:00:00 2001
From: Marko Budiselic <mbudiselicbuda@gmail.com>
Date: Thu, 22 Oct 2015 23:54:28 +0200
Subject: [PATCH] dynamic lib load work in progress :P
---
dc/README.md | 6 +++++
dc/example/db.hpp | 19 +++++++++++++++
dc/example/memsql.cpp | 28 ++++++++++++++++++++++
dc/example/mysql.cpp | 28 ++++++++++++++++++++++
dc/example/neo4j.cpp | 28 ++++++++++++++++++++++
dc/example/postgresql.cpp | 28 ++++++++++++++++++++++
dc/test.cpp | 50 ++++++++++++++++++++++++++++++++++-----
7 files changed, 181 insertions(+), 6 deletions(-)
create mode 100644 dc/example/db.hpp
create mode 100644 dc/example/memsql.cpp
create mode 100644 dc/example/mysql.cpp
create mode 100644 dc/example/neo4j.cpp
create mode 100644 dc/example/postgresql.cpp
diff --git a/dc/README.md b/dc/README.md
index 2bf28fe09..116d58797 100644
--- a/dc/README.md
+++ b/dc/README.md
@@ -1 +1,7 @@
## Dynamic Code
+
+```
+cd example
+clang++ -std=c++1y mysql.cpp -o ../tmp/mysql.so -shared -fPIC
+clang++ -std=c++1y test.cpp -o test.out -ldl
+```
diff --git a/dc/example/db.hpp b/dc/example/db.hpp
new file mode 100644
index 000000000..a507968df
--- /dev/null
+++ b/dc/example/db.hpp
@@ -0,0 +1,19 @@
+#ifndef MEMGRAPH_DL_EXAMPLE_DB_HPP
+#define MEMGRAPH_DL_EXAMPLE_DB_HPP
+
+#include <iostream>
+
+using namespace std;
+
+class db
+{
+public:
+ virtual void name() const;
+ virtual void type() const;
+ virtual ~db() {}
+};
+
+typedef db* (*produce_t)();
+typedef void (*destruct_t)(db*);
+
+#endif
diff --git a/dc/example/memsql.cpp b/dc/example/memsql.cpp
new file mode 100644
index 000000000..b8fa37ef4
--- /dev/null
+++ b/dc/example/memsql.cpp
@@ -0,0 +1,28 @@
+#include "db.hpp"
+
+class memsql : public db
+{
+public:
+
+ void name() const override
+ {
+ cout << "MemSQL" << endl;
+ }
+
+ void type() const override
+ {
+ cout << "InMemory" << endl;
+ }
+
+ ~memsql() {}
+};
+
+extern "C" db* produce()
+{
+ return new memsql();
+}
+
+extern "C" void destruct(db* p)
+{
+ delete p;
+}
diff --git a/dc/example/mysql.cpp b/dc/example/mysql.cpp
new file mode 100644
index 000000000..3b6c1bb2c
--- /dev/null
+++ b/dc/example/mysql.cpp
@@ -0,0 +1,28 @@
+#include "db.hpp"
+
+class mysql : public db
+{
+public:
+
+ virtual void name() const
+ {
+ cout << "MySQL" << endl;
+ }
+
+ virtual void type() const
+ {
+ cout << "Relational" << endl;
+ }
+
+ ~mysql() {}
+};
+
+extern "C" db* produce()
+{
+ return new mysql();
+}
+
+extern "C" void destruct(db* p)
+{
+ delete p;
+}
diff --git a/dc/example/neo4j.cpp b/dc/example/neo4j.cpp
new file mode 100644
index 000000000..0418bed74
--- /dev/null
+++ b/dc/example/neo4j.cpp
@@ -0,0 +1,28 @@
+#include "db.hpp"
+
+class neo4j : public db
+{
+public:
+
+ void name() const override
+ {
+ cout << "Neo4j" << endl;
+ }
+
+ void type() const override
+ {
+ cout << "Graph" << endl;
+ }
+
+ ~neo4j() {}
+};
+
+extern "C" db* produce()
+{
+ return new neo4j();
+}
+
+extern "C" void destruct(db* p)
+{
+ delete p;
+}
diff --git a/dc/example/postgresql.cpp b/dc/example/postgresql.cpp
new file mode 100644
index 000000000..34b5445fe
--- /dev/null
+++ b/dc/example/postgresql.cpp
@@ -0,0 +1,28 @@
+#include "db.hpp"
+
+class postgresql : public db
+{
+public:
+
+ void name() const override
+ {
+ cout << "PostgreSQL" << endl;
+ }
+
+ void type() const override
+ {
+ cout << "Relational" << endl;
+ }
+
+ ~postgresql() {}
+};
+
+extern "C" db* produce()
+{
+ return new postgresql();
+}
+
+extern "C" void destruct(db* p)
+{
+ delete p;
+}
diff --git a/dc/test.cpp b/dc/test.cpp
index 685aa8cde..ba582ad92 100644
--- a/dc/test.cpp
+++ b/dc/test.cpp
@@ -4,6 +4,8 @@
#include <vector>
#include <iterator>
#include <cstdlib>
+#include <dlfcn.h>
+#include "example/db.hpp"
// TODO: clang++ file.cpp -o file.so -shared -fPIC
@@ -32,15 +34,51 @@ std::string prints(const Args&... args)
return join(strings, " ");
}
+db* database(const std::string& lib_path, const std::string& factory_method)
+{
+ // load lib
+ void* db_lib = dlopen(lib_path.c_str(), RTLD_LAZY);
+ if (!db_lib) {
+ cerr << "Cannot load library: " << dlerror() << '\n';
+ return nullptr;
+ }
+ dlerror();
+
+ // load produce method
+ produce_t produce_db = (produce_t) dlsym(db_lib, factory_method.c_str());
+ const char* dlsym_error = dlerror();
+ if (dlsym_error) {
+ cerr << "Cannot load symbol create: " << dlsym_error << '\n';
+ return nullptr;
+ }
+
+ // load destroy method
+ // destruct_t destruct_db = (destruct_t) dlsym(db_lib, "destruct");
+ // dlsym_error = dlerror();
+ // if (dlsym_error) {
+ // cerr << "Cannot load symbol destroy: " << dlsym_error << '\n';
+ // return nullptr;
+ // }
+
+ db *instance = produce_db();
+
+ return instance;
+}
+
int main()
{
- string tmp_file_path = "tmp/tmp.cpp";
- string tmp_so_path = "tmp/tmp.so";
- string for_compile = "#include <iostream>\nint main() { std::cout << \"test\" << std::endl; return 0; }";
+ // string tmp_file_path = "tmp/tmp.cpp";
+ // string tmp_so_path = "tmp/tmp.so";
+ // string for_compile = "#include <iostream>\nint main() { std::cout << \"test\" << std::endl; return 0; }";
- write(tmp_file_path, for_compile);
- string test_command = prints("clang++", tmp_file_path, "-o", "test.out");
- system(test_command.c_str());
+ // write(tmp_file_path, for_compile);
+ // string test_command = prints("clang++", tmp_file_path, "-o", "test.out");
+ // system(test_command.c_str());
+
+ db *mysql = database("./tmp/mysql.so", "produce");
+ if (mysql) {
+ mysql->name();
+ }
return 0;
}