mil_tools/TemporaryFile.hpp: Add TemporaryFile class

src/mil_common/mil_tools/CMakeLists.txt

@@ -60,4 +60,11 @@ if(BUILD_TESTING)
     $<INSTALL_INTERFACE:include>
   )
   target_link_libraries(${PROJECT_NAME}_os_test ${PROJECT_NAME})
+
+  ament_add_gtest(${PROJECT_NAME}_random_test test/random.cpp)
+  target_include_directories(${PROJECT_NAME}_random_test PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+    $<INSTALL_INTERFACE:include>
+  )
+  target_link_libraries(${PROJECT_NAME}_random_test ${PROJECT_NAME})
 endif()

src/mil_common/mil_tools/include/mil_tools/os/TemporaryFile.hpp

@@ -0,0 +1,87 @@
+#pragma once
+
+#include <fcntl.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <filesystem>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "mil_tools/os/FileDescriptor.hpp"
+#include "mil_tools/string.hpp"
+
+namespace mil_tools::os
+{
+
+class TemporaryFile
+{
+private:
+  std::string name_;
+  std::string tmp_path_ = std::filesystem::temp_directory_path().string();
+  void create()
+  {
+    char* name = path().data();
+    int raw_fd = mkstemp(name);
+    if (raw_fd < 0)
+    {
+      throw std::runtime_error("Failed to create temporary file " + path() + ": " + strerror(errno));
+    }
+    name_ = mil_tools::string::removeprefix(name, tmp_path_);
+    fd_ = FileDescriptor(raw_fd);
+  }
+  FileDescriptor fd_;
+
+public:
+  TemporaryFile() : name_("tmpXXXXXX")
+  {
+    create();
+  };
+  explicit TemporaryFile(std::string const& name) : name_(name)
+  {
+    create();
+  };
+  inline std::string name() const
+  {
+    return name_;
+  }
+  inline std::string path() const
+  {
+    return tmp_path_ + "/" + name_;
+  }
+  ~TemporaryFile()
+  {
+    close();
+  };
+  inline bool valid()
+  {
+    return fd_.valid();
+  }
+  void close()
+  {
+    ::unlink(path().data());
+    fd_.close();
+  };
+  void write(std::string const& data)
+  {
+    fd_.write(data);
+    fsync(fd_.get());
+  };
+  void write(std::vector<char> const& data)
+  {
+    fd_.write(data);
+    fsync(fd_.get());
+  };
+  std::string read_as_string(int size)
+  {
+    return fd_.read_as_string(size);
+  };
+  std::vector<char> read(int size)
+  {
+    return fd_.read(size);
+  };
+};
+
+}  // namespace mil_tools::os

src/mil_common/mil_tools/test/os.cpp

@@ -7,6 +7,7 @@
 #include <iostream>
 
 #include "mil_tools/fs/path.hpp"
+#include "mil_tools/os/TemporaryFile.hpp"
 
 TEST(mil_tools_os, open)
 {
@@ -21,24 +22,21 @@ TEST(mil_tools_os, open)
 TEST(mil_tools_os, write)
 {
   // create file if not eist
-  std::ofstream(mil_tools::fs::path::expanduser("~/mil2/tmp.txt"));
-
-  // write with fd
-  std::string filename = mil_tools::fs::path::expanduser("~/mil2/tmp.txt");
-  auto fd = mil_tools::os::open(filename, O_RDWR | O_CREAT);
-  mil_tools::os::write(fd.get(), "hello");
-  fd.write(" world");
-  fd.close();
+  mil_tools::os::TemporaryFile tmpfile;
+  tmpfile.write("hello world");
 
   // check contents
-  std::ifstream file(filename);
+  std::ifstream file(tmpfile.path());
+  assert(file.is_open());
   std::string line;
   std::getline(file, line);
   EXPECT_EQ(line, "hello world");
   file.close();
+  tmpfile.close();
 
-  // delete file
-  std::remove(filename.c_str());
+  // ensure temp file was actually deleted
+  file.open(tmpfile.path());
+  EXPECT_FALSE(file.is_open());
 }
 
 int main(int argc, char **argv)