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-rw-r--r--include/libcamera/internal/shared_mem_object.h103
1 files changed, 53 insertions, 50 deletions
diff --git a/include/libcamera/internal/shared_mem_object.h b/include/libcamera/internal/shared_mem_object.h
index a9970059..9b1d9393 100644
--- a/include/libcamera/internal/shared_mem_object.h
+++ b/include/libcamera/internal/shared_mem_object.h
@@ -1,85 +1,98 @@
/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
- * Copyright (C) 2023, Raspberry Pi Ltd
+ * Copyright (C) 2023 Raspberry Pi Ltd
+ * Copyright (C) 2024 Andrei Konovalov
+ * Copyright (C) 2024 Dennis Bonke
*
- * shared_mem_object.h - Helper class for shared memory allocations
+ * shared_mem_object.h - Helpers for shared memory allocations
*/
#pragma once
-#include <fcntl.h>
#include <stddef.h>
+#include <stdint.h>
#include <string>
#include <sys/mman.h>
-#include <sys/stat.h>
-#include <unistd.h>
+#include <type_traits>
#include <utility>
#include <libcamera/base/class.h>
#include <libcamera/base/shared_fd.h>
+#include <libcamera/base/span.h>
namespace libcamera {
-template<class T>
-class SharedMemObject
+class SharedMem
{
public:
- static constexpr std::size_t kSize = sizeof(T);
+ SharedMem();
- SharedMemObject()
- : obj_(nullptr)
+ SharedMem(const std::string &name, std::size_t size);
+ SharedMem(SharedMem &&rhs);
+
+ virtual ~SharedMem();
+
+ SharedMem &operator=(SharedMem &&rhs);
+
+ const SharedFD &fd() const
{
+ return fd_;
}
- template<class... Args>
- SharedMemObject(const std::string &name, Args &&...args)
- : name_(name), obj_(nullptr)
+ Span<uint8_t> mem() const
{
- void *mem;
- int ret;
+ return mem_;
+ }
- ret = memfd_create(name_.c_str(), MFD_CLOEXEC);
- if (ret < 0)
- return;
+ explicit operator bool() const
+ {
+ return !mem_.empty();
+ }
- fd_ = SharedFD(std::move(ret));
- if (!fd_.isValid())
- return;
+private:
+ LIBCAMERA_DISABLE_COPY(SharedMem)
- ret = ftruncate(fd_.get(), kSize);
- if (ret < 0)
- return;
+ SharedFD fd_;
- mem = mmap(nullptr, kSize, PROT_READ | PROT_WRITE, MAP_SHARED,
- fd_.get(), 0);
- if (mem == MAP_FAILED)
+ Span<uint8_t> mem_;
+};
+
+template<class T, typename = std::enable_if_t<std::is_standard_layout<T>::value>>
+class SharedMemObject : public SharedMem
+{
+public:
+ static constexpr std::size_t kSize = sizeof(T);
+
+ SharedMemObject()
+ : SharedMem(), obj_(nullptr)
+ {
+ }
+
+ template<class... Args>
+ SharedMemObject(const std::string &name, Args &&...args)
+ : SharedMem(name, kSize), obj_(nullptr)
+ {
+ if (mem().empty())
return;
- obj_ = new (mem) T(std::forward<Args>(args)...);
+ obj_ = new (mem().data()) T(std::forward<Args>(args)...);
}
SharedMemObject(SharedMemObject<T> &&rhs)
+ : SharedMem(std::move(rhs))
{
- this->name_ = std::move(rhs.name_);
- this->fd_ = std::move(rhs.fd_);
this->obj_ = rhs.obj_;
rhs.obj_ = nullptr;
}
~SharedMemObject()
{
- if (obj_) {
+ if (obj_)
obj_->~T();
- munmap(obj_, kSize);
- }
}
- /* Make SharedMemObject non-copyable for now. */
- LIBCAMERA_DISABLE_COPY(SharedMemObject)
-
SharedMemObject<T> &operator=(SharedMemObject<T> &&rhs)
{
- this->name_ = std::move(rhs.name_);
- this->fd_ = std::move(rhs.fd_);
+ SharedMem::operator=(std::move(rhs));
this->obj_ = rhs.obj_;
rhs.obj_ = nullptr;
return *this;
@@ -105,19 +118,9 @@ public:
return *obj_;
}
- const SharedFD &fd() const
- {
- return fd_;
- }
-
- explicit operator bool() const
- {
- return !!obj_;
- }
-
private:
- std::string name_;
- SharedFD fd_;
+ LIBCAMERA_DISABLE_COPY(SharedMemObject)
+
T *obj_;
};