build: work around VS2015 issue in ICU <56

The particular ufile.c is from
http://bugs.icu-project.org/trac/changeset/37704
and should be OK for ICU 54 and 55.

Also, adds general mechanism for floating patches on top of ICU.

Fixes: #2279
PR-URL: #2283
Reviewed-By: João Reis <reis@janeasystems.com>

configure

@@ -781,15 +781,22 @@ def write(filename, data):
 
 do_not_edit = '# Do not edit. Generated by the configure script.\n'
 
-def glob_to_var(dir_base, dir_sub):
+def glob_to_var(dir_base, dir_sub, patch_dir):
   list = []
   dir_all = os.path.join(dir_base, dir_sub)
   files = os.walk(dir_all)
   for ent in files:
     (path, dirs, files) = ent
     for file in files:
       if file.endswith('.cpp') or file.endswith('.c') or file.endswith('.h'):
-        list.append('%s/%s' % (dir_sub, file))
+        # srcfile uses "slash" as dir separator as its output is consumed by gyp
+        srcfile = '%s/%s' % (dir_sub, file)
+        if patch_dir:
+          patchfile = '%s/%s/%s' % (dir_base, patch_dir, file)
+          if os.path.isfile(patchfile):
+            srcfile = '%s/%s' % (patch_dir, file)
+            print 'Using version-specific floating patch %s' % patchfile
+        list.append(srcfile)
     break
   return list
 
@@ -1011,7 +1018,7 @@ def configure_intl(o):
   for i in icu_src:
     var  = 'icu_src_%s' % i
     path = '../../deps/icu/source/%s' % icu_src[i]
-    icu_config['variables'][var] = glob_to_var('tools/icu', path)
+    icu_config['variables'][var] = glob_to_var('tools/icu', path, 'patches/%s/source/%s' % (icu_ver_major, icu_src[i]) )
   # write updated icu_config.gypi with a bunch of paths
   write(icu_config_name, do_not_edit +
         pprint.pformat(icu_config, indent=2) + '\n')

tools/icu/patches/54/source/io/ufile.c

@@ -0,0 +1,360 @@
+/*
+******************************************************************************
+*
+*   Copyright (C) 1998-2015, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*
+******************************************************************************
+*
+* File ufile.c
+*
+* Modification History:
+*
+*   Date        Name        Description
+*   11/19/98    stephen     Creation.
+*   03/12/99    stephen     Modified for new C API.
+*   06/16/99    stephen     Changed T_LocaleBundle to u_locbund
+*   07/19/99    stephen     Fixed to use ucnv's default codepage.
+******************************************************************************
+*/
+
+/*
+ * fileno is not declared when building with GCC in strict mode.
+ */
+#if defined(__GNUC__) && defined(__STRICT_ANSI__)
+#undef __STRICT_ANSI__
+#endif
+
+#include "locmap.h"
+#include "unicode/ustdio.h"
+
+#if !UCONFIG_NO_CONVERSION
+
+#include "ufile.h"
+#include "unicode/uloc.h"
+#include "unicode/ures.h"
+#include "unicode/ucnv.h"
+#include "unicode/ustring.h"
+#include "cstring.h"
+#include "cmemory.h"
+
+#if U_PLATFORM_USES_ONLY_WIN32_API && !defined(fileno)
+/* Windows likes to rename Unix-like functions */
+#define fileno _fileno
+#endif
+
+static UFILE*
+finit_owner(FILE         *f,
+              const char *locale,
+              const char *codepage,
+              UBool       takeOwnership
+              )
+{
+    UErrorCode status = U_ZERO_ERROR;
+    UFILE     *result;
+    if(f == NULL) {
+        return 0;
+    }
+    result = (UFILE*) uprv_malloc(sizeof(UFILE));
+    if(result == NULL) {
+        return 0;
+    }
+
+    uprv_memset(result, 0, sizeof(UFILE));
+    result->fFileno = fileno(f);
+
+#if U_PLATFORM_USES_ONLY_WIN32_API && _MSC_VER < 1900
+    /*
+     * Below is a very old workaround (ICU ticket:231).
+     *
+     * Previously, 'FILE*' from inside and outside ICU's DLL
+     * were different, because they pointed into local copies
+     * of the io block. At least by VS 2015 the implementation
+     * is something like:
+     *    stdio = _acrt_iob_func(0)
+     * .. which is a function call, so should return the same pointer
+     * regardless of call site.
+     * As of _MSC_VER 1900 this patch is retired, at 16 years old.
+     */
+    if (0 <= result->fFileno && result->fFileno <= 2) {
+        /* stdin, stdout and stderr need to be special cased for Windows 98 */
+#if _MSC_VER >= 1400
+        result->fFile = &__iob_func()[_fileno(f)];
+#else
+        result->fFile = &_iob[_fileno(f)];
+#endif
+    }
+    else
+#endif
+    {
+        result->fFile = f;
+    }
+
+    result->str.fBuffer = result->fUCBuffer;
+    result->str.fPos    = result->fUCBuffer;
+    result->str.fLimit  = result->fUCBuffer;
+
+#if !UCONFIG_NO_FORMATTING
+        /* if locale is 0, use the default */
+        if(u_locbund_init(&result->str.fBundle, locale) == 0) {
+            /* DO NOT FCLOSE HERE! */
+            uprv_free(result);
+            return 0;
+        }
+#endif
+
+    /* If the codepage is not "" use the ucnv_open default behavior */
+    if(codepage == NULL || *codepage != '\0') {
+        result->fConverter = ucnv_open(codepage, &status);
+    }
+    /* else result->fConverter is already memset'd to NULL. */
+
+    if(U_SUCCESS(status)) {
+        result->fOwnFile = takeOwnership;
+    }
+    else {
+#if !UCONFIG_NO_FORMATTING
+        u_locbund_close(&result->str.fBundle);
+#endif
+        /* DO NOT fclose here!!!!!! */
+        uprv_free(result);
+        result = NULL;
+    }
+
+    return result;
+}
+
+U_CAPI UFILE* U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_finit(FILE          *f,
+        const char    *locale,
+        const char    *codepage)
+{
+    return finit_owner(f, locale, codepage, FALSE);
+}
+
+U_CAPI UFILE* U_EXPORT2
+u_fadopt(FILE         *f,
+        const char    *locale,
+        const char    *codepage)
+{
+    return finit_owner(f, locale, codepage, TRUE);
+}
+
+U_CAPI UFILE* U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fopen(const char    *filename,
+        const char    *perm,
+        const char    *locale,
+        const char    *codepage)
+{
+    UFILE     *result;
+    FILE     *systemFile = fopen(filename, perm);
+    if(systemFile == 0) {
+        return 0;
+    }
+
+    result = finit_owner(systemFile, locale, codepage, TRUE);
+
+    if (!result) {
+        /* Something bad happened.
+           Maybe the converter couldn't be opened. */
+        fclose(systemFile);
+    }
+
+    return result; /* not a file leak */
+}
+
+U_CAPI UFILE* U_EXPORT2
+u_fopen_u(const UChar   *filename,
+        const char    *perm,
+        const char    *locale,
+        const char    *codepage)
+{
+    UFILE     *result;
+    char buffer[256];
+
+    u_austrcpy(buffer, filename);
+
+    result = u_fopen(buffer, perm, locale, codepage);
+#if U_PLATFORM_USES_ONLY_WIN32_API
+    /* Try Windows API _wfopen if the above fails. */
+    if (!result) {
+        FILE *systemFile = _wfopen(filename, (UChar*)perm);
+        if (systemFile) {
+            result = finit_owner(systemFile, locale, codepage, TRUE);
+        }
+        if (!result) {
+            /* Something bad happened.
+               Maybe the converter couldn't be opened. */
+            fclose(systemFile);
+        }
+    }
+#endif
+    return result; /* not a file leak */
+}
+
+U_CAPI UFILE* U_EXPORT2
+u_fstropen(UChar *stringBuf,
+           int32_t      capacity,
+           const char  *locale)
+{
+    UFILE *result;
+
+    if (capacity < 0) {
+        return NULL;
+    }
+
+    result = (UFILE*) uprv_malloc(sizeof(UFILE));
+    /* Null pointer test */
+    if (result == NULL) {
+    	return NULL; /* Just get out. */
+    }
+    uprv_memset(result, 0, sizeof(UFILE));
+    result->str.fBuffer = stringBuf;
+    result->str.fPos    = stringBuf;
+    result->str.fLimit  = stringBuf+capacity;
+
+#if !UCONFIG_NO_FORMATTING
+    /* if locale is 0, use the default */
+    if(u_locbund_init(&result->str.fBundle, locale) == 0) {
+        /* DO NOT FCLOSE HERE! */
+        uprv_free(result);
+        return 0;
+    }
+#endif
+
+    return result;
+}
+
+U_CAPI UBool U_EXPORT2
+u_feof(UFILE  *f)
+{
+    UBool endOfBuffer;
+    if (f == NULL) {
+        return TRUE;
+    }
+    endOfBuffer = (UBool)(f->str.fPos >= f->str.fLimit);
+    if (f->fFile != NULL) {
+        return endOfBuffer && feof(f->fFile);
+    }
+    return endOfBuffer;
+}
+
+U_CAPI void U_EXPORT2
+u_fflush(UFILE *file)
+{
+    ufile_flush_translit(file);
+    ufile_flush_io(file);
+    if (file->fFile) {
+        fflush(file->fFile);
+    }
+    else if (file->str.fPos < file->str.fLimit) {
+        *(file->str.fPos++) = 0;
+    }
+    /* TODO: flush input */
+}
+
+U_CAPI void
+u_frewind(UFILE *file)
+{
+    u_fflush(file);
+    ucnv_reset(file->fConverter);
+    if (file->fFile) {
+        rewind(file->fFile);
+        file->str.fLimit = file->fUCBuffer;
+        file->str.fPos   = file->fUCBuffer;
+    }
+    else {
+        file->str.fPos = file->str.fBuffer;
+    }
+}
+
+U_CAPI void U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fclose(UFILE *file)
+{
+    if (file) {
+        u_fflush(file);
+        ufile_close_translit(file);
+
+        if(file->fOwnFile)
+            fclose(file->fFile);
+
+#if !UCONFIG_NO_FORMATTING
+        u_locbund_close(&file->str.fBundle);
+#endif
+
+        ucnv_close(file->fConverter);
+        uprv_free(file);
+    }
+}
+
+U_CAPI FILE* U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fgetfile(    UFILE         *f)
+{
+    return f->fFile;
+}
+
+#if !UCONFIG_NO_FORMATTING
+
+U_CAPI const char*  U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fgetlocale(    UFILE        *file)
+{
+    return file->str.fBundle.fLocale;
+}
+
+U_CAPI int32_t U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fsetlocale(UFILE      *file,
+             const char *locale)
+{
+    u_locbund_close(&file->str.fBundle);
+
+    return u_locbund_init(&file->str.fBundle, locale) == 0 ? -1 : 0;
+}
+
+#endif
+
+U_CAPI const char* U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fgetcodepage(UFILE        *file)
+{
+    UErrorCode     status = U_ZERO_ERROR;
+    const char     *codepage = NULL;
+
+    if (file->fConverter) {
+        codepage = ucnv_getName(file->fConverter, &status);
+        if(U_FAILURE(status))
+            return 0;
+    }
+    return codepage;
+}
+
+U_CAPI int32_t U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fsetcodepage(    const char    *codepage,
+               UFILE        *file)
+{
+    UErrorCode status = U_ZERO_ERROR;
+    int32_t retVal = -1;
+
+    /* We use the normal default codepage for this system, and not the one for the locale. */
+    if ((file->str.fPos == file->str.fBuffer) && (file->str.fLimit == file->str.fBuffer)) {
+        ucnv_close(file->fConverter);
+        file->fConverter = ucnv_open(codepage, &status);
+        if(U_SUCCESS(status)) {
+            retVal = 0;
+        }
+    }
+    return retVal;
+}
+
+
+U_CAPI UConverter * U_EXPORT2 /* U_CAPI ... U_EXPORT2 added by Peter Kirk 17 Nov 2001 */
+u_fgetConverter(UFILE *file)
+{
+    return file->fConverter;
+}
+#if !UCONFIG_NO_FORMATTING
+U_CAPI const UNumberFormat* U_EXPORT2 u_fgetNumberFormat(UFILE *file)
+{
+    return u_locbund_getNumberFormat(&file->str.fBundle, UNUM_DECIMAL);
+}
+#endif
+
+#endif