tauri-workspace/ui/tauri.h

/*
 * MIT License
 *
 * Copyright (c) 2017 Serge Zaitsev, (c) 2019 Tauri Apps
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#ifndef WEBVIEW_H
#define WEBVIEW_H

#ifdef __cplusplus
extern "C" {
#endif

#ifdef WEBVIEW_STATIC
#define WEBVIEW_API static
#else
#define WEBVIEW_API extern
#endif

#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>

struct webview;

typedef void (*webview_external_invoke_cb_t)(struct webview *w,
                                             const char *arg);

struct webview {
  const char *url;
  const char *title;
  int width;
  int height;
  int resizable;
  int debug;
  webview_external_invoke_cb_t external_invoke_cb;
  struct webview_priv priv;
  void *userdata;
};

enum webview_dialog_type {
  WEBVIEW_DIALOG_TYPE_OPEN = 0,
  WEBVIEW_DIALOG_TYPE_SAVE = 1,
  WEBVIEW_DIALOG_TYPE_ALERT = 2
};

#define WEBVIEW_DIALOG_FLAG_FILE (0 << 0)
#define WEBVIEW_DIALOG_FLAG_DIRECTORY (1 << 0)

#define WEBVIEW_DIALOG_FLAG_INFO (1 << 1)
#define WEBVIEW_DIALOG_FLAG_WARNING (2 << 1)
#define WEBVIEW_DIALOG_FLAG_ERROR (3 << 1)
#define WEBVIEW_DIALOG_FLAG_ALERT_MASK (3 << 1)

typedef void (*webview_dispatch_fn)(struct webview *w, void *arg);

struct webview_dispatch_arg {
  webview_dispatch_fn fn;
  struct webview *w;
  void *arg;
};

#define DEFAULT_URL                                                            \
  "data:text/"                                                                 \
  "html,%3C%21DOCTYPE%20html%3E%0A%3Chtml%20lang=%22en%22%3E%0A%3Chead%3E%"    \
  "3Cmeta%20charset=%22utf-8%22%3E%3Cmeta%20http-equiv=%22X-UA-Compatible%22%" \
  "20content=%22IE=edge%22%3E%3C%2Fhead%3E%0A%3Cbody%3E%3Cdiv%20id=%22app%22%" \
  "3E%3C%2Fdiv%3E%3Cscript%20type=%22text%2Fjavascript%22%3E%3C%2Fscript%3E%"  \
  "3C%2Fbody%3E%0A%3C%2Fhtml%3E"

#define CSS_INJECT_FUNCTION                                                    \
  "(function(e){var "                                                          \
  "t=document.createElement('style'),d=document.head||document."               \
  "getElementsByTagName('head')[0];t.setAttribute('type','text/"               \
  "css'),t.styleSheet?t.styleSheet.cssText=e:t.appendChild(document."          \
  "createTextNode(e)),d.appendChild(t)})"

static const char *webview_check_url(const char *url) {
  if (url == NULL || strlen(url) == 0) {
    return DEFAULT_URL;
  }
  return url;
}

WEBVIEW_API int webview(const char *title, const char *url, int width,
                        int height, int resizable);

WEBVIEW_API int webview_init(struct webview *w);
WEBVIEW_API int webview_loop(struct webview *w, int blocking);
WEBVIEW_API int webview_eval(struct webview *w, const char *js);
WEBVIEW_API int webview_inject_css(struct webview *w, const char *css);
WEBVIEW_API void webview_set_title(struct webview *w, const char *title);
WEBVIEW_API void webview_set_fullscreen(struct webview *w, int fullscreen);
WEBVIEW_API void webview_set_color(struct webview *w, uint8_t r, uint8_t g,
                                   uint8_t b, uint8_t a);
WEBVIEW_API void webview_dialog(struct webview *w,
                                enum webview_dialog_type dlgtype, int flags,
                                const char *title, const char *arg,
                                char *result, size_t resultsz);
WEBVIEW_API void webview_dispatch(struct webview *w, webview_dispatch_fn fn,
                                  void *arg);
WEBVIEW_API void webview_terminate(struct webview *w);
WEBVIEW_API void webview_exit(struct webview *w);
WEBVIEW_API void webview_debug(const char *format, ...);
WEBVIEW_API void webview_print_log(const char *s);

#ifdef WEBVIEW_IMPLEMENTATION
#undef WEBVIEW_IMPLEMENTATION

WEBVIEW_API int webview(const char *title, const char *url, int width,
                        int height, int resizable) {
  struct webview webview;
  memset(&webview, 0, sizeof(webview));
  webview.title = title;
  webview.url = url;
  webview.width = width;
  webview.height = height;
  webview.resizable = resizable;
  int r = webview_init(&webview);
  if (r != 0) {
    return r;
  }
  while (webview_loop(&webview, 1) == 0) {
  }
  webview_exit(&webview);
  return 0;
}

WEBVIEW_API void webview_debug(const char *format, ...) {
  char buf[4096];
  va_list ap;
  va_start(ap, format);
  vsnprintf(buf, sizeof(buf), format, ap);
  webview_print_log(buf);
  va_end(ap);
}

static int webview_js_encode(const char *s, char *esc, size_t n) {
  int r = 1; /* At least one byte for trailing zero */
  for (; *s; s++) {
    const unsigned char c = *s;
    if (c >= 0x20 && c < 0x80 && strchr("<>\\'\"", c) == NULL) {
      if (n > 0) {
        *esc++ = c;
        n--;
      }
      r++;
    } else {
      if (n > 0) {
        snprintf(esc, n, "\\x%02x", (int)c);
        esc += 4;
        n -= 4;
      }
      r += 4;
    }
  }
  return r;
}

WEBVIEW_API int webview_inject_css(struct webview *w, const char *css) {
  int n = webview_js_encode(css, NULL, 0);
  char *esc = (char *)calloc(1, sizeof(CSS_INJECT_FUNCTION) + n + 4);
  if (esc == NULL) {
    return -1;
  }
  char *js = (char *)calloc(1, n);
  webview_js_encode(css, js, n);
  snprintf(esc, sizeof(CSS_INJECT_FUNCTION) + n + 4, "%s(\"%s\")",
           CSS_INJECT_FUNCTION, js);
  int r = webview_eval(w, esc);
  free(js);
  free(esc);
  return r;
}

#endif /* WEBVIEW_IMPLEMENTATION */

#ifdef __cplusplus
}
#endif

#endif /* WEBVIEW_H */