Create snapshot/mac and move some files from snapshot and util to there

util/mac/mach_o_image_symbol_table_reader.h

-// Copyright 2014 The Crashpad Authors. All rights reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#ifndef CRASHPAD_UTIL_MAC_MACH_O_IMAGE_SYMBOL_TABLE_READER_H_
-#define CRASHPAD_UTIL_MAC_MACH_O_IMAGE_SYMBOL_TABLE_READER_H_
-
-#include "base/basictypes.h"
-
-#include <map>
-#include <string>
-
-#include <mach/mach.h>
-#include <stdint.h>
-
-#include "util/mac/mach_o_image_segment_reader.h"
-#include "util/mac/process_reader.h"
-#include "util/mac/process_types.h"
-#include "util/misc/initialization_state_dcheck.h"
-
-namespace crashpad {
-
-//! \brief A reader for symbol tables in Mach-O images mapped into another
-//!     process.
-class MachOImageSymbolTableReader {
- public:
-  //! \brief Information about a symbol in a module’s symbol table.
-  //!
-  //! This is a more minimal form of the `nlist` (or `nlist_64`) structure,
-  //! only containing the equivalent of the `n_value` and `n_sect` fields.
-  struct SymbolInformation {
-    //! \brief The address of the symbol as it exists in the symbol table, not
-    //!     adjusted for any “slide.”
-    mach_vm_address_t value;
-
-    //! \brief The 1-based section index in the module in which the symbol is
-    //!     found.
-    //!
-    //! For symbols defined in a section (`N_SECT`), this is the section index
-    //! that can be passed to MachOImageReader::GetSectionAtIndex(), and \a
-    //! value will need to be adjusted for segment slide if the containing
-    //! segment slid when loaded. For absolute symbols (`N_ABS`), this will be
-    //! `NO_SECT` (`0`), and \a value must not be adjusted for segment slide.
-    uint8_t section;
-  };
-
-  // TODO(mark): Use unordered_map or a similar hash-based map? For now,
-  // std::map is fine because this map only stores external defined symbols,
-  // and there aren’t expected to be very many of those that performance would
-  // become a problem. std::map is also guaranteed to be part of the standard
-  // library, which isn’t the case for std::unordered_map, which requires the
-  // C++11 library. In reality, std::unordered_map does not appear to provide
-  // a performance advantage. It appears that the memory copies currently done
-  // by TaskMemory::Read() have substantially more impact on symbol table
-  // operations.
-  //
-  // This is public so that the type is available to
-  // MachOImageSymbolTableReaderInitializer.
-  typedef std::map<std::string, SymbolInformation> SymbolInformationMap;
-
-  MachOImageSymbolTableReader();
-  ~MachOImageSymbolTableReader();
-
-  //! \brief Reads the symbol table from another process.
-  //!
-  //! This method must only be called once on an object. This method must be
-  //! called successfully before any other method in this class may be called.
-  //!
-  //! \param[in] process_reader The reader for the remote process.
-  //! \param[in] symtab_command The `LC_SYMTAB` load command that identifies
-  //!     the symbol table.
-  //! \param[in] dysymtab_command The `LC_DYSYMTAB` load command that identifies
-  //!     dynamic symbol information within the symbol table. This load command
-  //!     is not present in all modules, and this parameter may be `nullptr` for
-  //!     modules that do not have this information. When present, \a
-  //!     dysymtab_command is an optimization that allows the symbol table
-  //!     reader to only examine symbol table entries known to be relevant for
-  //!     its purposes.
-  //! \param[in] linkedit_segment The `__LINKEDIT` segment. This segment should
-  //!     contain the data referenced by \a symtab_command and \a
-  //!     dysymtab_command. This may be any segment in the module, but by
-  //!     convention, the name `__LINKEDIT` is used for this purpose.
-  //! \param[in] module_info A string to be used in logged messages. This string
-  //!     is for diagnostic purposes only, and may be empty.
-  //!
-  //! \return `true` if the symbol table was read successfully. `false`
-  //!     otherwise, with an appropriate message logged.
-  bool Initialize(ProcessReader* process_reader,
-                  const process_types::symtab_command* symtab_command,
-                  const process_types::dysymtab_command* dysymtab_command,
-                  const MachOImageSegmentReader* linkedit_segment,
-                  const std::string& module_info);
-
-  //! \brief Looks up a symbol in the image’s symbol table.
-  //!
-  //! The returned information captures the symbol as it exists in the image’s
-  //! symbol table, not adjusted for any “slide.”
-  //!
-  //! \param[in] name The name of the symbol to look up, “mangled” or
-  //!     “decorated” appropriately. For example, use `"_main"` to look up the
-  //!     symbol for the C `main()` function, and use `"__Z4Funcv"` to look up
-  //!     the symbol for the C++ `Func()` function.
-  //!
-  //! \return A SymbolInformation* object with information about the symbol if
-  //!     it was found, or `nullptr` if the symbol was not found or if an error
-  //!     occurred. On error, a warning message will also be logged. The caller
-  //!     does not take ownership; the lifetime of the returned object is scoped
-  //!     to the lifetime of this MachOImageSymbolTableReader object.
-  //!
-  //! \note Symbol values returned via this interface are not adjusted for
-  //!     “slide.” For slide-adjusted values, use the higher-level
-  //!     MachOImageReader::LookUpExternalDefinedSymbol() interface.
-  const SymbolInformation* LookUpExternalDefinedSymbol(
-      const std::string& name) const;
-
- private:
-  SymbolInformationMap external_defined_symbols_;
-  InitializationStateDcheck initialized_;
-
-  DISALLOW_COPY_AND_ASSIGN(MachOImageSymbolTableReader);
-};
-
-}  // namespace crashpad
-
-#endif  // CRASHPAD_UTIL_MAC_MACH_O_IMAGE_SYMBOL_TABLE_READER_H_