Everywhere: Hoist the Libraries folder to the top-level

Libraries/LibCore/AnonymousBuffer.cpp

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2021, Andreas Kling <andreas@ladybird.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Try.h>
+#include <LibCore/AnonymousBuffer.h>
+#include <LibCore/System.h>
+#include <LibIPC/File.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+namespace Core {
+
+ErrorOr<AnonymousBuffer> AnonymousBuffer::create_with_size(size_t size)
+{
+    auto fd = TRY(Core::System::anon_create(size, O_CLOEXEC));
+    return create_from_anon_fd(fd, size);
+}
+
+ErrorOr<NonnullRefPtr<AnonymousBufferImpl>> AnonymousBufferImpl::create(int fd, size_t size)
+{
+    auto* data = mmap(nullptr, round_up_to_power_of_two(size, PAGE_SIZE), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+    if (data == MAP_FAILED)
+        return Error::from_errno(errno);
+    return AK::adopt_nonnull_ref_or_enomem(new (nothrow) AnonymousBufferImpl(fd, size, data));
+}
+
+AnonymousBufferImpl::~AnonymousBufferImpl()
+{
+    if (m_fd != -1) {
+        auto rc = close(m_fd);
+        VERIFY(rc == 0);
+    }
+    auto rc = munmap(m_data, round_up_to_power_of_two(m_size, PAGE_SIZE));
+    VERIFY(rc == 0);
+}
+
+ErrorOr<AnonymousBuffer> AnonymousBuffer::create_from_anon_fd(int fd, size_t size)
+{
+    auto impl = TRY(AnonymousBufferImpl::create(fd, size));
+    return AnonymousBuffer(move(impl));
+}
+
+AnonymousBufferImpl::AnonymousBufferImpl(int fd, size_t size, void* data)
+    : m_fd(fd)
+    , m_size(size)
+    , m_data(data)
+{
+}
+
+}