[DSC] Simplify file mapping to fix intermittent unrelocated pointers

The `FileAccessorCache`'s LRU eviction could discard a file's mapped
data after slide info had already been applied to it. Future accesses to
the file produced a fresh mapping, but failed to reapply the slide info.
This could result in pointers not correctly being slid, such as in
https://github.com/Vector35/binaryninja-api/issues/7689.

The LRU cache existed to stay within OS file descriptor limits, since
the old `MappedFile` held its fd open for the lifetime of the mapping.
There's no real reason for it to hold the file descriptor open like
this. Closing it after `mmap` is sufficient to avoid the file descriptor
limits.

`MappedFileRegion` replaces the combination of `FileAccessorCache`,
`WeakFileAccessor`, and `MappedFileAccessor`. It closes the fd
immediately after mmap, so all files can stay mapped without consuming
descriptors, making the cache unnecessary.

`MappedFileRegion` is owned directly by the `CacheEntry` for its full
lifetime. Slide info is applied exactly once to each `MappedFileRegion`.

1 files changed, 0 insertions, 103 deletions

diff --git a/view/sharedcache/core/MappedFileAccessor.h b/view/sharedcache/core/MappedFileAccessor.h
deleted file mode 100644
index 35d2d5e7..00000000
--- a/view/sharedcache/core/MappedFileAccessor.h
+++ /dev/null
@@ -1,103 +0,0 @@
-#pragma once
-
-#include "binaryninjaapi.h"
-#include "MappedFile.h"
-
-#include <cstdint>
-#include <list>
-
-class UnmappedAccessException : public std::exception
-{
-	uint64_t m_address;
-	uint64_t m_fileLen;
-
-public:
-	explicit UnmappedAccessException(uint64_t address, uint64_t fileLength) : m_address(address), m_fileLen(fileLength)
-	{}
-
-	virtual const char* what() const throw()
-	{
-		thread_local std::string message;
-		message =
-			fmt::format("Tried to access unmapped address {0:x} for file with length of {1:x}", m_address, m_fileLen);
-		return message.c_str();
-	}
-};
-
-// std::enable_shared_from_this allows weak pointers to "revive" the shared pointer in the FileAccessorCache.
-class MappedFileAccessor : public std::enable_shared_from_this<MappedFileAccessor>
-{
-	MappedFile m_file;
-	bool m_dirty = false;
-
-public:
-	explicit MappedFileAccessor(MappedFile file) : m_file(std::move(file)) {}
-
-	~MappedFileAccessor() = default;
-
-	MappedFileAccessor(const MappedFileAccessor&) = delete;
-
-	MappedFileAccessor& operator=(const MappedFileAccessor&) = delete;
-
-	MappedFileAccessor(MappedFileAccessor&&) noexcept = default;
-
-	MappedFileAccessor& operator=(MappedFileAccessor&&) noexcept = default;
-
-	static std::shared_ptr<MappedFileAccessor> Open(const std::string& filePath);
-
-	size_t Length() const { return m_file.len; };
-
-	void* Data() const { return m_file._mmap; };
-
-	bool IsDirty() const { return m_dirty; }
-
-	/**
-	 * Writes to files are implemented for performance reasons and should be treated with utmost care
-	 *
-	 * They _MAY_ disappear as _soon_ as you release the lock on the file.
-	 * They may also NOT disappear for the lifetime of the application.
-	 *
-	 * The former is more likely to occur when concurrent DSC processing is happening. The latter is the typical
-	 * scenario.
-	 *
-	 * This is used explicitly for slide information in a locked scope and _NOTHING_ else. It should probably not be
-	 * used for anything else.
-	 *
-	 * \param address The address to write the pointer to
-	 * \param pointer The pointer to be written
-	 */
-	void WritePointer(size_t address, size_t pointer);
-
-	std::string ReadNullTermString(size_t address, size_t maxLength = -1) const;
-
-	uint8_t ReadUInt8(size_t address) const;
-
-	int8_t ReadInt8(size_t address) const;
-
-	uint16_t ReadUInt16(size_t address) const;
-
-	int16_t ReadInt16(size_t address) const;
-
-	uint32_t ReadUInt32(size_t address) const;
-
-	int32_t ReadInt32(size_t address) const;
-
-	uint64_t ReadUInt64(size_t address) const;
-
-	int64_t ReadInt64(size_t address) const;
-
-	BinaryNinja::DataBuffer ReadBuffer(size_t addr, size_t length) const;
-
-	// Returns a range of pointers within the mapped memory region corresponding to
-	// {addr, length}.
-	// WARNING: The pointers returned by this method is only valid for the lifetime
-	// of this file accessor.
-	// TODO: This should use std::span<const uint8_t> once the minimum supported
-	// C++ version supports it.
-	std::pair<const uint8_t*, const uint8_t*> ReadSpan(size_t addr, size_t length);
-
-	void Read(void* dest, size_t addr, size_t length) const;
-
-	template <typename T>
-	T Read(size_t address) const;
-};