mingw.c: Fix complier warnings for a 64 bit msvc

Remove some complier warnings from msvc in compat/mingw.c for value
truncation from 64 bit to 32 bit integers.

Compiling compat/mingw.c under a 64 bit version of msvc produces
warnings. An "int" is 32 bit, and ssize_t or size_t should be 64 bit
long. Prepare compat/vcbuild/include/unistd.h to have a 64 bit type
_ssize_t, when _WIN64 is defined and 32 bit otherwise.

Further down in this include file, as before, ssize_t is defined as
_ssize_t, if needed.

Use size_t instead of int for all variables that hold the result of
strlen() or wcslen() (which cannot be negative).

Use ssize_t to hold the return value of read().

Signed-off-by: Sören Krecker <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>

Author: soekkle

compat/compiler.h

@@ -9,7 +9,7 @@
 
 static inline void get_compiler_info(struct strbuf *info)
 {
-	int len = info->len;
+	size_t len = info->len;
 #ifdef __clang__
 	strbuf_addf(info, "clang: %s\n", __clang_version__);
 #elif defined(__GNUC__)
@@ -27,7 +27,7 @@ static inline void get_compiler_info(struct strbuf *info)
 
 static inline void get_libc_info(struct strbuf *info)
 {
-	int len = info->len;
+	size_t len = info->len;
 
 #ifdef __GLIBC__
 	strbuf_addf(info, "glibc: %s\n", gnu_get_libc_version());

compat/mingw.c

@@ -1049,7 +1049,7 @@ int mingw_chmod(const char *filename, int mode)
  */
 static int has_valid_directory_prefix(wchar_t *wfilename)
 {
-	int n = wcslen(wfilename);
+	size_t n = wcslen(wfilename);
 
 	while (n > 0) {
 		wchar_t c = wfilename[--n];
@@ -1628,7 +1628,8 @@ static const char *parse_interpreter(const char *cmd)
 {
 	static char buf[MAX_PATH];
 	char *p, *opt;
-	int n, fd;
+	ssize_t n; /* read() can return negative values */
+	int fd;
 
 	/* don't even try a .exe */
 	n = strlen(cmd);
@@ -1752,7 +1753,7 @@ static char *path_lookup(const char *cmd, int exe_only)
 {
 	const char *path;
 	char *prog = NULL;
-	int len = strlen(cmd);
+	size_t len = strlen(cmd);
 	int isexe = len >= 4 && !strcasecmp(cmd+len-4, ".exe");
 
 	if (strpbrk(cmd, "/\\"))
@@ -2389,7 +2390,7 @@ char *mingw_getenv(const char *name)
 #define GETENV_MAX_RETAIN 64
 	static char *values[GETENV_MAX_RETAIN];
 	static int value_counter;
-	int len_key, len_value;
+	size_t len_key, len_value;
 	wchar_t *w_key;
 	char *value;
 	wchar_t w_value[32768];
@@ -2401,7 +2402,8 @@ char *mingw_getenv(const char *name)
 	/* We cannot use xcalloc() here because that uses getenv() itself */
 	w_key = calloc(len_key, sizeof(wchar_t));
 	if (!w_key)
-		die("Out of memory, (tried to allocate %u wchar_t's)", len_key);
+		die("Out of memory, (tried to allocate %"PRIuMAX" wchar_t's)",
+			(uintmax_t)len_key);
 	xutftowcs(w_key, name, len_key);
 	/* GetEnvironmentVariableW() only sets the last error upon failure */
 	SetLastError(ERROR_SUCCESS);
@@ -2416,7 +2418,8 @@ char *mingw_getenv(const char *name)
 	/* We cannot use xcalloc() here because that uses getenv() itself */
 	value = calloc(len_value, sizeof(char));
 	if (!value)
-		die("Out of memory, (tried to allocate %u bytes)", len_value);
+		die("Out of memory, (tried to allocate %"PRIuMAX" bytes)",
+			(uintmax_t)len_value);
 	xwcstoutf(value, w_value, len_value);
 
 	/*
@@ -2434,7 +2437,7 @@ char *mingw_getenv(const char *name)
 
 int mingw_putenv(const char *namevalue)
 {
-	int size;
+	size_t size;
 	wchar_t *wide, *equal;
 	BOOL result;
 
@@ -2444,7 +2447,8 @@ int mingw_putenv(const char *namevalue)
 	size = strlen(namevalue) * 2 + 1;
 	wide = calloc(size, sizeof(wchar_t));
 	if (!wide)
-		die("Out of memory, (tried to allocate %u wchar_t's)", size);
+		die("Out of memory, (tried to allocate %" PRIuMAX " wchar_t's)",
+		    (uintmax_t)size);
 	xutftowcs(wide, namevalue, size);
 	equal = wcschr(wide, L'=');
 	if (!equal)
@@ -4072,7 +4076,8 @@ static BOOL WINAPI handle_ctrl_c(DWORD ctrl_type)
  */
 int wmain(int argc, const wchar_t **wargv)
 {
-	int i, maxlen, exit_status;
+	int i, exit_status;
+	size_t maxlen;
 	char *buffer, **save;
 	const char **argv;
 

compat/vcbuild/include/unistd.h

@@ -14,7 +14,11 @@ typedef _mode_t	mode_t;
 
 #ifndef _SSIZE_T_
 #define _SSIZE_T_
+#ifdef _WIN64
+typedef __int64 _ssize_t;
+#else
 typedef long _ssize_t;
+#endif /* _WIN64 */
 
 #ifndef	_OFF_T_
 #define	_OFF_T_