1/*
2 * libjingle
3 * Copyright 2004--2010, Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#ifndef TALK_BASE_LATEBINDINGSYMBOLTABLE_H_
29#define TALK_BASE_LATEBINDINGSYMBOLTABLE_H_
30
31#include <string.h>
32
33#include "talk/base/common.h"
34
35namespace talk_base {
36
37#ifdef POSIX
38typedef void *DllHandle;
39#else
40#error Not implemented for this platform
41#endif
42
43// This is the base class for "symbol table" classes to simplify the dynamic
44// loading of symbols from DLLs. Currently the implementation only supports
45// Linux and OS X, and pure C symbols (or extern "C" symbols that wrap C++
46// functions).  Sub-classes for specific DLLs are generated via the "supermacro"
47// files latebindingsymboltable.h.def and latebindingsymboltable.cc.def. See
48// talk/sound/pulseaudiosymboltable.(h|cc) for an example.
49class LateBindingSymbolTable {
50 public:
51  struct TableInfo {
52    const char *dll_name;
53    int num_symbols;
54    // Array of size num_symbols.
55    const char *const *symbol_names;
56  };
57
58  LateBindingSymbolTable(const TableInfo *info, void **table);
59  ~LateBindingSymbolTable();
60
61  bool IsLoaded() const;
62  // Loads the DLL and the symbol table. Returns true iff the DLL and symbol
63  // table loaded successfully.
64  bool Load();
65  // Like load, but allows overriding the dll path for when the dll path is
66  // dynamic.
67  bool LoadFromPath(const char *dll_path);
68  void Unload();
69
70  // Gets the raw OS handle to the DLL. Be careful what you do with it.
71  DllHandle GetDllHandle() const { return handle_; }
72
73 private:
74  void ClearSymbols();
75
76  const TableInfo *info_;
77  void **table_;
78  DllHandle handle_;
79  bool undefined_symbols_;
80
81  DISALLOW_COPY_AND_ASSIGN(LateBindingSymbolTable);
82};
83
84}  // namespace talk_base
85
86#endif  // TALK_BASE_LATEBINDINGSYMBOLTABLE_H_
87