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[debian/gzip] / lib / msvc-inval.h
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+/* Invalid parameter handler for MSVC runtime libraries.
+   Copyright (C) 2011-2012 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef _MSVC_INVAL_H
+#define _MSVC_INVAL_H
+
+/* With MSVC runtime libraries with the "invalid parameter handler" concept,
+   functions like fprintf(), dup2(), or close() crash when the caller passes
+   an invalid argument.  But POSIX wants error codes (such as EINVAL or EBADF)
+   instead.
+   This file defines macros that turn such an invalid parameter notification
+   into a non-local exit.  An error code can then be produced at the target
+   of this exit.  You can thus write code like
+
+     TRY_MSVC_INVAL
+       {
+         <Code that can trigger an invalid parameter notification
+          but does not do 'return', 'break', 'continue', nor 'goto'.>
+       }
+     CATCH_MSVC_INVAL
+       {
+         <Code that handles an invalid parameter notification
+          but does not do 'return', 'break', 'continue', nor 'goto'.>
+       }
+     DONE_MSVC_INVAL;
+
+   This entire block expands to a single statement.
+
+   The handling of invalid parameters can be done in three ways:
+
+     * The default way, which is reasonable for programs (not libraries):
+       AC_DEFINE([MSVC_INVALID_PARAMETER_HANDLING], [DEFAULT_HANDLING])
+
+     * The way for libraries that make "hairy" calls (like close(-1), or
+       fclose(fp) where fileno(fp) is closed, or simply getdtablesize()):
+       AC_DEFINE([MSVC_INVALID_PARAMETER_HANDLING], [HAIRY_LIBRARY_HANDLING])
+
+     * The way for libraries that make no "hairy" calls:
+       AC_DEFINE([MSVC_INVALID_PARAMETER_HANDLING], [SANE_LIBRARY_HANDLING])
+ */
+
+#define DEFAULT_HANDLING       0
+#define HAIRY_LIBRARY_HANDLING 1
+#define SANE_LIBRARY_HANDLING  2
+
+#if HAVE_MSVC_INVALID_PARAMETER_HANDLER \
+    && !(MSVC_INVALID_PARAMETER_HANDLING == SANE_LIBRARY_HANDLING)
+/* A native Windows platform with the "invalid parameter handler" concept,
+   and either DEFAULT_HANDLING or HAIRY_LIBRARY_HANDLING.  */
+
+# if MSVC_INVALID_PARAMETER_HANDLING == DEFAULT_HANDLING
+/* Default handling.  */
+
+#  ifdef __cplusplus
+extern "C" {
+#  endif
+
+/* Ensure that the invalid parameter handler in installed that just returns.
+   Because we assume no other part of the program installs a different
+   invalid parameter handler, this solution is multithread-safe.  */
+extern void gl_msvc_inval_ensure_handler (void);
+
+#  ifdef __cplusplus
+}
+#  endif
+
+#  define TRY_MSVC_INVAL \
+     do                                                                        \
+       {                                                                       \
+         gl_msvc_inval_ensure_handler ();                                      \
+         if (1)
+#  define CATCH_MSVC_INVAL \
+         else
+#  define DONE_MSVC_INVAL \
+       }                                                                       \
+     while (0)
+
+# else
+/* Handling for hairy libraries.  */
+
+#  include <excpt.h>
+
+/* Gnulib can define its own status codes, as described in the page
+   "Raising Software Exceptions" on microsoft.com
+   <http://msdn.microsoft.com/en-us/library/het71c37.aspx>.
+   Our status codes are composed of
+     - 0xE0000000, mandatory for all user-defined status codes,
+     - 0x474E550, a API identifier ("GNU"),
+     - 0, 1, 2, ..., used to distinguish different status codes from the
+       same API.  */
+#  define STATUS_GNULIB_INVALID_PARAMETER (0xE0000000 + 0x474E550 + 0)
+
+#  if defined _MSC_VER
+/* A compiler that supports __try/__except, as described in the page
+   "try-except statement" on microsoft.com
+   <http://msdn.microsoft.com/en-us/library/s58ftw19.aspx>.
+   With __try/__except, we can use the multithread-safe exception handling.  */
+
+#   ifdef __cplusplus
+extern "C" {
+#   endif
+
+/* Ensure that the invalid parameter handler in installed that raises a
+   software exception with code STATUS_GNULIB_INVALID_PARAMETER.
+   Because we assume no other part of the program installs a different
+   invalid parameter handler, this solution is multithread-safe.  */
+extern void gl_msvc_inval_ensure_handler (void);
+
+#   ifdef __cplusplus
+}
+#   endif
+
+#   define TRY_MSVC_INVAL \
+      do                                                                       \
+        {                                                                      \
+          gl_msvc_inval_ensure_handler ();                                     \
+          __try
+#   define CATCH_MSVC_INVAL \
+          __except (GetExceptionCode () == STATUS_GNULIB_INVALID_PARAMETER     \
+                    ? EXCEPTION_EXECUTE_HANDLER                                \
+                    : EXCEPTION_CONTINUE_SEARCH)
+#   define DONE_MSVC_INVAL \
+        }                                                                      \
+      while (0)
+
+#  else
+/* Any compiler.
+   We can only use setjmp/longjmp.  */
+
+#   include <setjmp.h>
+
+#   ifdef __cplusplus
+extern "C" {
+#   endif
+
+struct gl_msvc_inval_per_thread
+{
+  /* The restart that will resume execution at the code between
+     CATCH_MSVC_INVAL and DONE_MSVC_INVAL.  It is enabled only between
+     TRY_MSVC_INVAL and CATCH_MSVC_INVAL.  */
+  jmp_buf restart;
+
+  /* Tells whether the contents of restart is valid.  */
+  int restart_valid;
+};
+
+/* Ensure that the invalid parameter handler in installed that passes
+   control to the gl_msvc_inval_restart if it is valid, or raises a
+   software exception with code STATUS_GNULIB_INVALID_PARAMETER otherwise.
+   Because we assume no other part of the program installs a different
+   invalid parameter handler, this solution is multithread-safe.  */
+extern void gl_msvc_inval_ensure_handler (void);
+
+/* Return a pointer to the per-thread data for the current thread.  */
+extern struct gl_msvc_inval_per_thread *gl_msvc_inval_current (void);
+
+#   ifdef __cplusplus
+}
+#   endif
+
+#   define TRY_MSVC_INVAL \
+      do                                                                       \
+        {                                                                      \
+          struct gl_msvc_inval_per_thread *msvc_inval_current;                 \
+          gl_msvc_inval_ensure_handler ();                                     \
+          msvc_inval_current = gl_msvc_inval_current ();                       \
+          /* First, initialize gl_msvc_inval_restart.  */                      \
+          if (setjmp (msvc_inval_current->restart) == 0)                       \
+            {                                                                  \
+              /* Then, mark it as valid.  */                                   \
+              msvc_inval_current->restart_valid = 1;
+#   define CATCH_MSVC_INVAL \
+              /* Execution completed.                                          \
+                 Mark gl_msvc_inval_restart as invalid.  */                    \
+              msvc_inval_current->restart_valid = 0;                           \
+            }                                                                  \
+          else                                                                 \
+            {                                                                  \
+              /* Execution triggered an invalid parameter notification.        \
+                 Mark gl_msvc_inval_restart as invalid.  */                    \
+              msvc_inval_current->restart_valid = 0;
+#   define DONE_MSVC_INVAL \
+            }                                                                  \
+        }                                                                      \
+      while (0)
+
+#  endif
+
+# endif
+
+#else
+/* A platform that does not need to the invalid parameter handler,
+   or when SANE_LIBRARY_HANDLING is desired.  */
+
+/* The braces here avoid GCC warnings like
+   "warning: suggest explicit braces to avoid ambiguous 'else'".  */
+# define TRY_MSVC_INVAL \
+    do                                                                         \
+      {                                                                        \
+        if (1)
+# define CATCH_MSVC_INVAL \
+        else
+# define DONE_MSVC_INVAL \
+      }                                                                        \
+    while (0)
+
+#endif
+
+#endif /* _MSVC_INVAL_H */