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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef BASE_NATIVE_LIBRARY_H_
      6 #define BASE_NATIVE_LIBRARY_H_
      7 
      8 // This file defines a cross-platform "NativeLibrary" type which represents
      9 // a loadable module.
     10 
     11 #include <string>
     12 
     13 #include "base/base_export.h"
     14 #include "base/strings/string_piece.h"
     15 #include "build/build_config.h"
     16 
     17 #if defined(OS_WIN)
     18 #include <windows.h>
     19 #elif defined(OS_MACOSX)
     20 #import <CoreFoundation/CoreFoundation.h>
     21 #endif  // OS_*
     22 
     23 namespace base {
     24 
     25 class FilePath;
     26 
     27 #if defined(OS_WIN)
     28 using NativeLibrary = HMODULE;
     29 #elif defined(OS_MACOSX)
     30 enum NativeLibraryType {
     31   BUNDLE,
     32   DYNAMIC_LIB
     33 };
     34 enum NativeLibraryObjCStatus {
     35   OBJC_UNKNOWN,
     36   OBJC_PRESENT,
     37   OBJC_NOT_PRESENT,
     38 };
     39 struct NativeLibraryStruct {
     40   NativeLibraryType type;
     41   CFBundleRefNum bundle_resource_ref;
     42   NativeLibraryObjCStatus objc_status;
     43   union {
     44     CFBundleRef bundle;
     45     void* dylib;
     46   };
     47 };
     48 using NativeLibrary = NativeLibraryStruct*;
     49 #elif defined(OS_POSIX)
     50 using NativeLibrary = void*;
     51 #endif  // OS_*
     52 
     53 struct BASE_EXPORT NativeLibraryLoadError {
     54 #if defined(OS_WIN)
     55   NativeLibraryLoadError() : code(0) {}
     56 #endif  // OS_WIN
     57 
     58   // Returns a string representation of the load error.
     59   std::string ToString() const;
     60 
     61 #if defined(OS_WIN)
     62   DWORD code;
     63 #else
     64   std::string message;
     65 #endif  // OS_WIN
     66 };
     67 
     68 struct BASE_EXPORT NativeLibraryOptions {
     69   NativeLibraryOptions() = default;
     70   NativeLibraryOptions(const NativeLibraryOptions& options) = default;
     71 
     72   // If |true|, a loaded library is required to prefer local symbol resolution
     73   // before considering global symbols. Note that this is already the default
     74   // behavior on most systems. Setting this to |false| does not guarantee the
     75   // inverse, i.e., it does not force a preference for global symbols over local
     76   // ones.
     77   bool prefer_own_symbols = false;
     78 };
     79 
     80 // Loads a native library from disk.  Release it with UnloadNativeLibrary when
     81 // you're done.  Returns NULL on failure.
     82 // If |error| is not NULL, it may be filled in on load error.
     83 BASE_EXPORT NativeLibrary LoadNativeLibrary(const FilePath& library_path,
     84                                             NativeLibraryLoadError* error);
     85 
     86 // Loads a native library from disk.  Release it with UnloadNativeLibrary when
     87 // you're done.  Returns NULL on failure.
     88 // If |error| is not NULL, it may be filled in on load error.
     89 BASE_EXPORT NativeLibrary LoadNativeLibraryWithOptions(
     90     const FilePath& library_path,
     91     const NativeLibraryOptions& options,
     92     NativeLibraryLoadError* error);
     93 
     94 // Unloads a native library.
     95 BASE_EXPORT void UnloadNativeLibrary(NativeLibrary library);
     96 
     97 // Gets a function pointer from a native library.
     98 BASE_EXPORT void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
     99                                                       StringPiece name);
    100 
    101 // Returns the full platform specific name for a native library.
    102 // |name| must be ASCII.
    103 // For example:
    104 // "mylib" returns "mylib.dll" on Windows, "libmylib.so" on Linux,
    105 // "libmylib.dylib" on Mac.
    106 BASE_EXPORT std::string GetNativeLibraryName(StringPiece name);
    107 
    108 }  // namespace base
    109 
    110 #endif  // BASE_NATIVE_LIBRARY_H_
    111