add: [ipc] implementation of shm (TBD)

src/libipc/platform/win/mmap.h

@@ -54,7 +54,7 @@ void mmap_close(HANDLE h) {
  * @param type Combinable open modes, create | open
  * @return File mapping object HANDLE, NULL on error
  */
-HANDLE mmap_open(std::string file, std::size_t size, mode::type type) noexcept {
+HANDLE mmap_open(std::string const &file, std::size_t size, mode::type type) noexcept {
   LIBIMP_LOG_();
   if (file.empty()) {
     log.error("file name is empty.");
@@ -72,6 +72,9 @@ HANDLE mmap_open(std::string file, std::size_t size, mode::type type) noexcept {
       log.error("OpenFileMapping fails. error = {}", sys::error_msg(sys::error_code()));
     }
     return h;
+  } else if (!(type & mode::create)) {
+    log.error("mode type is invalid. type = {}", type);
+    return NULL;
   }
   /// @brief Creates or opens a named or unnamed file mapping object for a specified file.
   HANDLE h = ::CreateFileMapping(INVALID_HANDLE_VALUE, detail::get_sa(), PAGE_READWRITE | SEC_COMMIT,
@@ -84,6 +87,7 @@ HANDLE mmap_open(std::string file, std::size_t size, mode::type type) noexcept {
   // (with its current size, not the specified size), and GetLastError returns ERROR_ALREADY_EXISTS.
   if ((type == mode::create) && (::GetLastError() == ERROR_ALREADY_EXISTS)) {
     mmap_close(h);
+    log.info("the file being created already exists. file = {}, type = {}", file, type);
     return NULL;
   }
   return h;
@@ -148,7 +152,29 @@ void mmap_release(HANDLE h, LPCVOID mem) {
 } // namespace
 
 ::LIBIMP_::result<shm_t> shm_open(std::string name, std::size_t size, mode::type type) noexcept {
-  return {};
+  LIBIMP_LOG_();
+  auto h = mmap_open(name, size, type);
+  if (h == NULL) {
+    log.error("mmap_open failed.");
+    return {nullptr, *sys::error_code()};
+  }
+  auto mem = mmap_memof(h);
+  if (mem == NULL) {
+    log.warning("mmap_memof failed.");
+  }
+  return new shm_handle{std::move(name), mmap_sizeof(mem), mem, h};
+}
+
+::LIBIMP_::result_code shm_close(shm_t h) noexcept {
+  LIBIMP_LOG_();
+  if (h == nullptr) {
+    log.error("shm handle is null.");
+    return {};
+  }
+  auto shm = static_cast<shm_handle *>(h);
+  mmap_release(shm->h_fmap, shm->memp);
+  delete shm;
+  return {true};
 }
 
 LIBIPC_NAMESPACE_END_

src/libipc/shm.cpp

@@ -1,3 +1,6 @@
+
+#include "libimp/log.h"
+
 #include "libimp/detect_plat.h"
 #if defined(LIBIMP_OS_WIN)
 #include "libipc/platform/win/mmap.h"
@@ -7,6 +10,34 @@
 
 LIBIPC_NAMESPACE_BEG_
 
+void *shm_get(shm_t h) noexcept {
+  LIBIMP_LOG_();
+  if (h == nullptr) {
+    log.error("shm handle is null.");
+    return {};
+  }
+  auto shm = static_cast<shm_handle *>(h);
+  return shm->memp;
+}
 
+std::size_t shm_size(shm_t h) noexcept {
+  LIBIMP_LOG_();
+  if (h == nullptr) {
+    log.error("shm handle is null.");
+    return {};
+  }
+  auto shm = static_cast<shm_handle *>(h);
+  return shm->f_sz;
+}
+
+std::string shm_file(shm_t h) noexcept {
+  LIBIMP_LOG_();
+  if (h == nullptr) {
+    log.error("shm handle is null.");
+    return {};
+  }
+  auto shm = static_cast<shm_handle *>(h);
+  return shm->file;
+}
 
 LIBIPC_NAMESPACE_END_

test/test_ipc_shm.cpp

@@ -4,4 +4,27 @@
 #include "libipc/shm.h"
 
 TEST(shm, create_close) {
+  EXPECT_FALSE(ipc::shm_open("hello-ipc-shm", 1024, ipc::mode::none));
+
+  auto shm1 = ipc::shm_open("hello-ipc-shm", 1024, ipc::mode::create | ipc::mode::open);
+  EXPECT_TRUE(shm1);
+  EXPECT_FALSE(ipc::shm_open("hello-ipc-shm", 1024, ipc::mode::create));
+
+  auto pt1 = ipc::shm_get(*shm1);
+  EXPECT_TRUE(ipc::shm_size(*shm1) >= 1024);
+  EXPECT_NE(pt1, nullptr);
+  *(int *)pt1 = 0;
+
+  auto shm2 = ipc::shm_open("hello-ipc-shm", 0, ipc::mode::open);
+  EXPECT_TRUE(shm2);
+  EXPECT_EQ(ipc::shm_size(*shm1), ipc::shm_size(*shm2));
+  auto pt2 = ipc::shm_get(*shm1);
+  EXPECT_NE(pt2, nullptr);
+  EXPECT_EQ(*(int *)pt2, 0);
+  *(int *)pt1 = 1234;
+  EXPECT_EQ(*(int *)pt2, 1234);
+
+  EXPECT_TRUE(ipc::shm_close(*shm2));
+  EXPECT_TRUE(ipc::shm_close(*shm1));
+  EXPECT_FALSE(ipc::shm_close(nullptr));
 }