Run command: initial implementation to test in nodegit

generate/templates/manual/include/cmd.h

@@ -0,0 +1,56 @@
+#ifndef NODEGIT_CMD_H
+#define NODEGIT_CMD_H
+
+#include <string>
+#include <map>
+
+namespace nodegit {
+/**
+ * \class Cmd
+ * Abstract class holding a command to execute.
+ * 
+ * Instances of Cmd will store all the information needed to run the command,
+ * including environment variables to set, like CWD.
+ */
+class Cmd {
+public:
+  /* Enumeration describing the environment variables that Cmd will handle
+  * - kCWD: Current Working Directory.
+  */
+  enum class Env {kCWD};
+
+  Cmd() = default;
+  virtual ~Cmd() = default;
+  Cmd(const Cmd &other) = delete;
+  Cmd(Cmd &&other) = delete;
+  Cmd& operator=(const Cmd &other) = delete;
+  Cmd& operator=(Cmd &&other) = delete;
+
+  virtual std::string Command() const = 0;    // return the command to execute
+  virtual std::string Args() const = 0;   // return the arguments of the command if any
+
+  void SetEnv(Env env, const std::string &value) {
+    m_env[env] = value;
+  }
+  std::string GetEnv(Env env) const {
+    auto value = m_env.find(env);
+    if (value != m_env.end()) { return value->second; }
+    else { return std::string(""); }
+  }
+  void SetRedirectStdErr(bool redirectStdErr) {
+    m_redirectStdErr = redirectStdErr;
+  }
+  bool GetRedirectStdErr() const {
+    return m_redirectStdErr;
+  }
+
+  // TODO: turn private, and restrict set/get access with pre-validation if necessary
+  std::string out {};        // cmd output. TODO: stream here?
+  std::string errorMsg {};   // error message if the command execution failed
+
+private:
+  std::map<Env, std::string> m_env {};  // environment variables for this command
+  bool m_redirectStdErr {true};  // whether or not to redirect stderr to stdout
+};
+} // namespace nodegit
+#endif  // NODEGIT_CMD_H

generate/templates/manual/include/run_command.h

@@ -0,0 +1,62 @@
+#ifndef NODEGIT_RUN_CMD_H
+#define NODEGIT_RUN_CMD_H
+
+#include <iostream>
+#include <cstdio>
+#include <iostream>
+#include <stdexcept>
+#include <string>
+#include <array>
+#include "cmd.h"
+
+namespace nodegit {
+  // TODO:
+  // This is just a first testing version to run commands in MacOS, Linux and Win32
+  namespace runcommand {
+    /**
+     * \brief Executes a command.
+     * 
+     * \param cmd object storing all the information needed to execute a command. Result
+     * of the execution will also be stored here.
+     * \return true if command execution succeeded; false otherwise.
+     */
+    bool exec(Cmd *cmd) {
+      // TODO: sanitize path
+      assert (cmd != nullptr);
+      std::string cwd = cmd->GetEnv(Cmd::Env::kCWD);
+      std::string cmdCwd = cwd.empty() ? std::string("") : std::string("cd ").append(cwd).append(" && ");
+      std::string cmdArgs = cmd->Args();
+      std::string finalCmdArgs = cmdArgs.empty() ? std::string("") : std::string(" ").append(cmdArgs);
+      std::string cmdRedirectErr = cmd->GetRedirectStdErr() ? " 2>&1" : std::string("");
+      std::string finalCmd = cmdCwd + cmd->Command() + finalCmdArgs + cmdRedirectErr;
+
+#ifdef WIN32
+      auto pipe = _popen(finalCmd.c_str(), "r");
+#else
+      auto pipe = popen(finalCmd.c_str(), "r");
+#endif
+      if (!pipe) {
+        cmd->errorMsg = "popen() failed!";
+        return false;
+      }
+
+      std::array<char, 128> buffer {};
+      while (!feof(pipe)) {
+        if (fgets(buffer.data(), 128, pipe) != nullptr)
+          cmd->out += buffer.data();
+      }
+#ifdef WIN32
+      auto rc = _pclose(pipe);
+#else
+      auto rc = pclose(pipe);
+#endif
+
+      if (rc != EXIT_SUCCESS) {
+        cmd->errorMsg = "pclose() failed!";
+        return false;
+      }
+      return true;
+    }
+  } // namespace runcommand
+} // namespace nodegit
+#endif  // NODEGIT_RUN_CMD_H