Add Shm utilities, to be later used for plugin bridges

source/utils/CarlaShmUtils.hpp

@@ -0,0 +1,195 @@
+/*
+ * Carla shared memory utils
+ * Copyright (C) 2013 Filipe Coelho <falktx@falktx.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * For a full copy of the GNU General Public License see the GPL.txt file
+ */
+
+#ifndef __CARLA_SHM_UTILS_HPP__
+#define __CARLA_SHM_UTILS_HPP__
+
+#include "CarlaUtils.hpp"
+
+#ifdef CARLA_OS_WIN
+# include <vector>
+# include <windows.h>
+struct map_t { HANDLE map; void* ptr; };
+struct shm_t { HANDLE shm; std::vector<map_t> maps; };
+#else
+# include <fcntl.h>
+# include <sys/mman.h>
+typedef int shm_t;
+#endif
+
+// -------------------------------------------------
+// shared memory calls
+
+static inline
+bool carla_is_shm_valid(shm_t shm)
+{
+#ifdef CARLA_OS_WIN
+    return (shm.shm != nullptr && shm.shm != INVALID_HANDLE_VALUE);
+#else
+    return (shm >= 0);
+#endif
+}
+
+static inline
+void carla_shm_init(shm_t& shm)
+{
+#ifdef CARLA_OS_WIN
+    shm.shm = nullptr;
+    shm.maps.clear();
+#else
+    shm = -1;
+#endif
+}
+
+#ifdef CARLA_OS_WIN
+static inline
+shm_t carla_shm_attach_linux(const char* const name)
+{
+    CARLA_ASSERT(name != nullptr);
+
+    char shmName[std::strlen(name)+10];
+    std::strcpy(shmName, "/dev/shm/");
+    std::strcat(shmName, name);
+
+    shm_t ret;
+    ret.shm = CreateFileA(shmName, GENERIC_READ|GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
+
+    return ret;
+}
+#else
+static inline
+shm_t carla_shm_create(const char* const name)
+{
+    CARLA_ASSERT(name != nullptr);
+
+    return shm_open(name, O_RDWR | O_CREAT | O_EXCL, 0600);
+}
+
+static inline
+shm_t carla_shm_attach(const char* const name)
+{
+    CARLA_ASSERT(name != nullptr);
+
+    return shm_open(name, O_RDWR, 0);
+}
+#endif
+
+static inline
+void carla_shm_close(shm_t& shm)
+{
+    CARLA_ASSERT(carla_is_shm_valid(shm));
+
+#ifdef CARLA_OS_WIN
+    CARLA_ASSERT(shm.maps.empty());
+
+    CloseHandle(shm.shm);
+    shm.shm = nullptr;
+#else
+    close(shm);
+    shm = -1;
+#endif
+}
+
+static inline
+void* carla_shm_map(shm_t shm, const size_t size)
+{
+    CARLA_ASSERT(carla_is_shm_valid(shm));
+    CARLA_ASSERT(size > 0);
+
+#ifdef CARLA_OS_WIN
+    HANDLE map = CreateFileMapping(shm.shm, NULL, PAGE_READWRITE, size, size, NULL);
+
+    if (map == nullptr)
+        return nullptr;
+
+    HANDLE ptr = MapViewOfFile(map, FILE_MAP_COPY, 0, 0, size);
+
+    if (ptr == nullptr)
+        return nullptr;
+
+    map_t newMap;
+    newMap.map = map;
+    newMap.ptr = ptr;
+
+    shm.maps.push_back(newMap);
+
+    return ptr;
+#else
+    return mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, shm, 0);
+#endif
+}
+
+static inline
+void carla_shm_unmap(const shm_t shm, void* const ptr, const size_t size)
+{
+    CARLA_ASSERT(carla_is_shm_valid(shm));
+    CARLA_ASSERT(ptr != nullptr);
+    CARLA_ASSERT(size > 0);
+
+#ifdef CARLA_OS_WIN
+    CARLA_ASSERT(! shm.maps.empty());
+
+    for (auto it = shm.maps.begin(); it != shm.maps.end(); ++it)
+    {
+        map_t map(*it);
+
+        if (map.ptr == ptr)
+        {
+            UnmapViewOfFile(ptr);
+            CloseHandle(map.map);
+
+            shm.maps.erase(it);
+            break;
+        }
+    }
+
+    CARLA_ASSERT(false);
+
+    return;
+
+    // unused
+    (void)size;
+#else
+    munmap(ptr, size);
+    return;
+
+    // unused
+    (void)shm;
+#endif
+}
+
+// -------------------------------------------------
+// shared memory, templated calls
+
+template<typename T>
+static inline
+void carla_shm_map(shm_t shm, T* value)
+{
+    value = carla_shm_map(shm, sizeof(value));
+}
+
+template<typename T>
+static inline
+void carla_shm_unmap(const shm_t shm, T* value)
+{
+    carla_shm_unmap(shm, value, sizeof(value));
+    value = nullptr;
+}
+
+// -------------------------------------------------
+
+#endif // __CARLA_SHM_UTILS_HPP__