gears/base/common/common.h

   1 // Copyright 2006, Google Inc.
   2 //
   3 // Redistribution and use in source and binary forms, with or without
   4 // modification, are permitted provided that the following conditions are met:
   5 //
   6 //  1. Redistributions of source code must retain the above copyright notice,
   7 //     this list of conditions and the following disclaimer.
   8 //  2. Redistributions in binary form must reproduce the above copyright notice,
   9 //     this list of conditions and the following disclaimer in the documentation
  10 //     and/or other materials provided with the distribution.
  11 //  3. Neither the name of Google Inc. nor the names of its contributors may be
  12 //     used to endorse or promote products derived from this software without
  13 //     specific prior written permission.
  14 //
  15 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  16 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  17 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  18 // EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  19 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  21 // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  22 // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  23 // OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  24 // ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25 //
  26 // Common definitions for shared code between the Firefox and IE implementations
  27 // of Gears.
  28
  29 #ifndef GEARS_BASE_COMMON_COMMON_H__
  30 #define GEARS_BASE_COMMON_COMMON_H__
  31
  32 #include <float.h>
  33
  34 #include "common/genfiles/product_constants.h"  // from OUTDIR
  35 #include "gears/base/common/int_types.h"
  36 #include "gears/base/common/string16.h"
  37
  38 // TODO(michaeln): would be nice to be able to include base/basictypes.h
  39 // here rather than cherry pick and duplicate code, resolve issues with
  40 // doing so.
  41
  42 // ARRAYSIZE performs essentially the same calculation as arraysize,
  43 // but can be used on anonymous types or types defined inside
  44 // functions.  It's less safe than arraysize as it accepts some
  45 // (although not all) pointers.  Therefore, you should use arraysize
  46 // whenever possible.
  47 //
  48 // The expression ARRAYSIZE(a) is a compile-time constant of type
  49 // size_t.
  50 //
  51 // ARRAYSIZE catches a few type errors.  If you see a compiler error
  52 //
  53 //   "warning: division by zero in ..."
  54 //
  55 // when using ARRAYSIZE, you are (wrongfully) giving it a pointer.
  56 // You should only use ARRAYSIZE on statically allocated arrays.
  57 //
  58 // The following comments are on the implementation details, and can
  59 // be ignored by the users.
  60 //
  61 // ARRAYSIZE(arr) works by inspecting sizeof(arr) (the # of bytes in
  62 // the array) and sizeof(*(arr)) (the # of bytes in one array
  63 // element).  If the former is divisible by the latter, perhaps arr is
  64 // indeed an array, in which case the division result is the # of
  65 // elements in the array.  Otherwise, arr cannot possibly be an array,
  66 // and we generate a compiler error to prevent the code from
  67 // compiling.
  68 //
  69 // Since the size of bool is implementation-defined, we need to cast
  70 // !(sizeof(a) & sizeof(*(a))) to size_t in order to ensure the final
  71 // result has type size_t.
  72 //
  73 // This macro is not perfect as it wrongfully accepts certain
  74 // pointers, namely where the pointer size is divisible by the pointee
  75 // size.  Since all our code has to go through a 32-bit compiler,
  76 // where a pointer is 4 bytes, this means all pointers to a type whose
  77 // size is 3 or greater than 4 will be (righteously) rejected.
  78 //
  79 // Kudos to Jorg Brown for this simple and elegant implementation.
  80 //
  81 // - wan 2005-11-16
  82 //
  83 // Starting with Visual C++ 2005, ARRAYSIZE is defined in WinNT.h
  84 #if defined(_MSC_VER) && _MSC_VER >= 1400 && !defined(WINCE)
  85 #include <windows.h>
  86 #else
  87 #define ARRAYSIZE(a) \
  88   ((sizeof(a) / sizeof(*(a))) / \
  89    static_cast<size_t>(!(sizeof(a) % sizeof(*(a)))))
  90 #endif
  91
  92 #define WIDEN2(x) L ## x
  93 #define WIDEN(x) WIDEN2(x)
  94 #define __WFILE__ WIDEN(__FILE__)
  95
  96 #define GET_INTERNAL_ERROR_MESSAGE() \
  97     (std::string16(STRING16(L"Internal Error: " __WFILE__ L" Line ")) + \
  98      IntegerToString16(__LINE__))
  99
 100 // JS represents all numbers as doubles (IEEE 754). This
 101 // effectively gives the [-2^53, 2^53] range of integers that
 102 // can be represented by IEEE 754 without loss of precision.
 103 // For this reason, we cap the range of supported integers
 104 // to [-2^53, 2^53] by throwing an exception if the values
 105 // are outside this interval. This restriction is enforced,
 106 // for example, in GearsDatabase::get_lastInsertRowId() and
 107 // GearsResultSet::field().
 108 #define JS_INT_MAX (GG_LONGLONG(1) << DBL_MANT_DIG)  // 2^53
 109 #define JS_INT_MIN (-JS_INT_MAX)  // -2^53
 110
 111 // Defines private prototypes for copy constructor and assigment operator. Do
 112 // not implement these methods.
 113 #define DISALLOW_EVIL_CONSTRUCTORS(CLASS) \
 114  private:                                 \
 115   CLASS(const CLASS&);                    \
 116   CLASS& operator=(const CLASS&)
 117
 118
 119 // Macros for returning success/failure from scripted objects.
 120 //
 121 // TODO(cprince): Move these to base_class.h when IE has such a file.
 122 // This generic "common.h" should eventually go away.  Each file should
 123 // explicitly #include what it really needs, instead of using this catch-all.
 124 #if BROWSER_IE
 125
 126 #include "gears/base/common/common_ie.h"
 127
 128 #define RETURN_NORMAL()  return S_OK
 129 #define RETURN_EXCEPTION(msg)  \
 130   {  \
 131     /* AtlReportError has char* and WCHAR* versions */ \
 132     return AtlReportError(CLSID_NULL, msg); \
 133   }
 134
 135 #elif BROWSER_FF
 136
 137 #include "gears/base/common/common_ff.h"
 138
 139 #define RETURN_NORMAL()  return NS_OK
 140 #define RETURN_EXCEPTION(msg) \
 141   { \
 142     LOG(("Exception: %s", msg)); \
 143     return JsSetException(this->EnvPageJsContext(), this->GetJsRunner(), \
 144                           msg, !this->EnvIsWorker()); \
 145   }
 146
 147 #elif BROWSER_NPAPI
 148
 149 #include "gears/base/common/common_np.h"
 150
 151 #elif BROWSER_SAFARI
 152
 153 #include "gears/base/common/common_sf.h"
 154
 155 #define RETURN_NORMAL()  return 0
 156 #define RETURN_EXCEPTION(msg) \
 157 { \
 158     /* TODO(waylonis): Return e.message to try/catch blocks in Safari. */ \
 159     NSLog(@"Exception: %s", msg); \
 160     return 1; \
 161 }
 162
 163 #else
 164 #error "common.h: BROWSER_?? not defined."
 165 #endif
 166
 167
 168 #endif // GEARS_BASE_COMMON_COMMON_H__