apio
d43590e68c
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continuous-integration/drone/push Build is failing
The trick being caching lol.
52 lines
1.4 KiB
C++
52 lines
1.4 KiB
C++
#include "fs/devices/BlockDevice.h"
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#include "arch/MMU.h"
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#include <luna/Common.h>
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BlockDevice::BlockDevice(u64 block_size, u64 num_blocks) : m_cache(), m_block_size(block_size), m_num_blocks(num_blocks)
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{
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}
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Result<usize> BlockDevice::read(u8* buf, usize offset, usize length) const
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{
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if (length == 0) return 0;
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if (offset > size()) return 0;
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if (offset + length > size()) length = size() - offset;
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const usize saved = length;
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auto read_data = [&](u64 off, u64 len) -> Result<void> {
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const u64 block = offset / m_block_size;
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m_cache.lock();
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auto guard = make_scope_guard([&] { m_cache.unlock(); });
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auto* entry = TRY(m_cache.fetch_entry(block));
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if (entry->buffer.is_empty())
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{
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// TODO: What if the cache needs clearing in the middle of try_resize()? That could lead to some weird
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// state...
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TRY(entry->buffer.try_resize(m_block_size));
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TRY(read_block(entry->buffer, block));
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}
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memcpy(buf, entry->buffer.data() + off, len);
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offset += len;
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length -= len;
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buf += len;
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return {};
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};
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if (offset % m_block_size)
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{
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const u64 off = offset % m_block_size;
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const u64 len = min(m_block_size - off, length);
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TRY(read_data(off, len));
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}
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while (length >= m_block_size) { TRY(read_data(0, m_block_size)); }
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if (length) { TRY(read_data(0, length)); }
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return saved;
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}
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