Create process with wide chars on Windows

Windows does not support UTF-8, so pushing a file with non-ASCII
characters failed.

Convert the UTF-8 command line to a wide characters string and call
CreateProcessW().

Fixes <https://github.com/Genymobile/scrcpy/issues/422>

app/src/str_util.c

@@ -3,6 +3,11 @@
 #include <stdlib.h>
 #include <string.h>
 
+#ifdef _WIN32
+# include <windows.h>
+# include <tchar.h>
+#endif
+
 size_t xstrncpy(char *dest, const char *src, size_t n) {
     size_t i;
     for (i = 0; i < n - 1 && src[i] != '\0'; ++i)
@@ -47,3 +52,22 @@ char *strquote(const char *src) {
     quoted[len + 2] = '\0';
     return quoted;
 }
+
+#ifdef _WIN32
+
+wchar_t *utf8_to_wide_char(const char *utf8) {
+    int len = MultiByteToWideChar(CP_UTF8, 0, utf8, -1, NULL, 0);
+    if (!len) {
+        return NULL;
+    }
+
+    wchar_t *wide = malloc(len * sizeof(wchar_t));
+    if (!wide) {
+        return NULL;
+    }
+
+    MultiByteToWideChar(CP_UTF8, 0, utf8, -1, wide, len);
+    return wide;
+}
+
+#endif

app/src/str_util.h

@@ -20,4 +20,10 @@ size_t xstrjoin(char *dst, const char *const tokens[], char sep, size_t n);
 // returns the new allocated string, to be freed by the caller
 char *strquote(const char *src);
 
+#ifdef _WIN32
+// convert a UTF-8 string to a wchar_t string
+// returns the new allocated string, to be freed by the caller
+wchar_t *utf8_to_wide_char(const char *utf8);
+#endif
+
 #endif

app/src/sys/win/command.c

@@ -18,7 +18,7 @@ static int build_cmd(char *cmd, size_t len, const char *const argv[]) {
 }
 
 enum process_result cmd_execute(const char *path, const char *const argv[], HANDLE *handle) {
-    STARTUPINFO si;
+    STARTUPINFOW si;
     PROCESS_INFORMATION pi;
     memset(&si, 0, sizeof(si));
     si.cb = sizeof(si);
@@ -29,12 +29,19 @@ enum process_result cmd_execute(const char *path, const char *const argv[], HAND
         return PROCESS_ERROR_GENERIC;
     }
 
+    wchar_t *wide = utf8_to_wide_char(cmd);
+    if (!wide) {
+        LOGC("Cannot allocate wide char string");
+        return PROCESS_ERROR_GENERIC;
+    }
+
 #ifdef WINDOWS_NOCONSOLE
     int flags = CREATE_NO_WINDOW;
 #else
     int flags = 0;
 #endif
-    if (!CreateProcess(NULL, cmd, NULL, NULL, FALSE, flags, NULL, NULL, &si, &pi)) {
+    if (!CreateProcessW(NULL, wide, NULL, NULL, FALSE, flags, NULL, NULL, &si, &pi)) {
+        free(wide);
         *handle = NULL;
         if (GetLastError() == ERROR_FILE_NOT_FOUND) {
             return PROCESS_ERROR_MISSING_BINARY;
@@ -42,6 +49,7 @@ enum process_result cmd_execute(const char *path, const char *const argv[], HAND
         return PROCESS_ERROR_GENERIC;
     }
 
+    free(wide);
     *handle = pi.hProcess;
     return PROCESS_SUCCESS;
 }