1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
use parking_lot::ReentrantMutex;
use std::cell::{RefCell, UnsafeCell};
use std::ffi::{CStr, CString};
use std::ops::Drop;
use std::path::PathBuf;
use std::ptr;
use std::rc::Rc;

use crate::clipboard::{ClipboardBackend, ClipboardContext};
use crate::fonts::atlas::{FontAtlas, FontAtlasRefMut, FontId, SharedFontAtlas};
use crate::io::Io;
use crate::style::Style;
use crate::sys;
use crate::Ui;

/// An imgui-rs context.
///
/// A context needs to be created to access most library functions. Due to current Dear ImGui
/// design choices, at most one active Context can exist at any time. This limitation will likely
/// be removed in a future Dear ImGui version.
///
/// If you need more than one context, you can use suspended contexts. As long as only one context
/// is active at a time, it's possible to have multiple independent contexts.
///
/// # Examples
///
/// Creating a new active context:
/// ```
/// let ctx = arcdps_imgui::Context::create();
/// // ctx is dropped naturally when it goes out of scope, which deactivates and destroys the
/// // context
/// ```
///
/// Never try to create an active context when another one is active:
///
/// ```should_panic
/// let ctx1 = arcdps_imgui::Context::create();
///
/// let ctx2 = arcdps_imgui::Context::create(); // PANIC
/// ```
///
/// Suspending an active context allows you to create another active context:
///
/// ```
/// let ctx1 = arcdps_imgui::Context::create();
/// let suspended1 = ctx1.suspend();
/// let ctx2 = arcdps_imgui::Context::create(); // this is now OK
/// ```

#[derive(Debug)]
pub struct Context {
    raw: *mut sys::ImGuiContext,
    shared_font_atlas: Option<Rc<RefCell<SharedFontAtlas>>>,
    ini_filename: Option<CString>,
    log_filename: Option<CString>,
    platform_name: Option<CString>,
    renderer_name: Option<CString>,
    // we need to box this because we hand imgui a pointer to it,
    // and we don't want to deal with finding `clipboard_ctx`.
    // we also put it in an unsafecell since we're going to give
    // imgui a mutable pointer to it.
    clipboard_ctx: Box<UnsafeCell<ClipboardContext>>,
}

// This mutex needs to be used to guard all public functions that can affect the underlying
// Dear ImGui active context
static CTX_MUTEX: ReentrantMutex<()> = parking_lot::const_reentrant_mutex(());

fn clear_current_context() {
    unsafe {
        sys::igSetCurrentContext(ptr::null_mut());
    }
}
fn no_current_context() -> bool {
    let ctx = unsafe { sys::igGetCurrentContext() };
    ctx.is_null()
}

impl Context {
    /// Creates a new active imgui-rs context.
    ///
    /// # Panics
    ///
    /// Panics if an active context already exists
    #[doc(alias = "CreateContext")]
    pub fn create() -> Self {
        Self::create_internal(None)
    }
    /// Creates a new active imgui-rs context with a shared font atlas.
    ///
    /// # Panics
    ///
    /// Panics if an active context already exists
    #[doc(alias = "CreateContext")]
    pub fn create_with_shared_font_atlas(shared_font_atlas: Rc<RefCell<SharedFontAtlas>>) -> Self {
        Self::create_internal(Some(shared_font_atlas))
    }
    /// Gets the current context
    pub fn current() -> Self {
        let ctx = unsafe { sys::igGetCurrentContext() };
        Self {
            raw: ctx,
            shared_font_atlas: None,
            ini_filename: None,
            log_filename: None,
            platform_name: None,
            renderer_name: None,
            clipboard_ctx: Box::new(ClipboardContext::dummy().into()),
        }
    }
    /// Suspends this context so another context can be the active context.
    #[doc(alias = "CreateContext")]
    pub fn suspend(self) -> SuspendedContext {
        let _guard = CTX_MUTEX.lock();
        assert!(
            self.is_current_context(),
            "context to be suspended is not the active context"
        );
        clear_current_context();
        SuspendedContext(self)
    }
    /// Returns the path to the ini file, or None if not set
    pub fn ini_filename(&self) -> Option<PathBuf> {
        let io = self.io();
        if io.ini_filename.is_null() {
            None
        } else {
            let s = unsafe { CStr::from_ptr(io.ini_filename) };
            Some(PathBuf::from(s.to_str().ok()?))
        }
    }
    /// Sets the path to the ini file (default is "imgui.ini")
    ///
    /// Pass None to disable automatic .Ini saving.
    pub fn set_ini_filename<T: Into<Option<PathBuf>>>(&mut self, ini_filename: T) {
        let ini_filename: Option<PathBuf> = ini_filename.into();
        let ini_filename = ini_filename.and_then(|v| CString::new(v.to_str()?).ok());

        self.io_mut().ini_filename = ini_filename
            .as_ref()
            .map(|x| x.as_ptr())
            .unwrap_or(ptr::null());
        self.ini_filename = ini_filename;
    }
    /// Returns the path to the log file, or None if not set
    // TODO: why do we return an `Option<PathBuf>` instead of an `Option<&Path>`?
    pub fn log_filename(&self) -> Option<PathBuf> {
        let io = self.io();
        if io.log_filename.is_null() {
            None
        } else {
            let cstr = unsafe { CStr::from_ptr(io.log_filename) };
            Some(PathBuf::from(cstr.to_str().ok()?))
        }
    }
    /// Sets the log filename (default is "imgui_log.txt").
    pub fn set_log_filename<T: Into<Option<PathBuf>>>(&mut self, log_filename: T) {
        let log_filename = log_filename
            .into()
            .and_then(|v| CString::new(v.to_str()?).ok());

        self.io_mut().log_filename = log_filename
            .as_ref()
            .map(|x| x.as_ptr())
            .unwrap_or(ptr::null());
        self.log_filename = log_filename;
    }
    /// Returns the backend platform name, or None if not set
    pub fn platform_name(&self) -> Option<&str> {
        let io = self.io();
        if io.backend_platform_name.is_null() {
            None
        } else {
            let cstr = unsafe { CStr::from_ptr(io.backend_platform_name) };
            cstr.to_str().ok()
        }
    }
    /// Sets the backend platform name
    pub fn set_platform_name<T: Into<Option<String>>>(&mut self, platform_name: T) {
        let platform_name: Option<CString> =
            platform_name.into().and_then(|v| CString::new(v).ok());
        self.io_mut().backend_platform_name = platform_name
            .as_ref()
            .map(|x| x.as_ptr())
            .unwrap_or(ptr::null());
        self.platform_name = platform_name;
    }
    /// Returns the backend renderer name, or None if not set
    pub fn renderer_name(&self) -> Option<&str> {
        let io = self.io();
        if io.backend_renderer_name.is_null() {
            None
        } else {
            let cstr = unsafe { CStr::from_ptr(io.backend_renderer_name) };
            cstr.to_str().ok()
        }
    }
    /// Sets the backend renderer name
    pub fn set_renderer_name<T: Into<Option<String>>>(&mut self, renderer_name: T) {
        let renderer_name: Option<CString> =
            renderer_name.into().and_then(|v| CString::new(v).ok());

        self.io_mut().backend_renderer_name = renderer_name
            .as_ref()
            .map(|x| x.as_ptr())
            .unwrap_or(ptr::null());

        self.renderer_name = renderer_name;
    }
    /// Loads settings from a string slice containing settings in .Ini file format
    #[doc(alias = "LoadIniSettingsFromMemory")]
    pub fn load_ini_settings(&mut self, data: &str) {
        unsafe { sys::igLoadIniSettingsFromMemory(data.as_ptr() as *const _, data.len()) }
    }
    /// Saves settings to a mutable string buffer in .Ini file format
    #[doc(alias = "SaveInitSettingsToMemory")]
    pub fn save_ini_settings(&mut self, buf: &mut String) {
        let data = unsafe { CStr::from_ptr(sys::igSaveIniSettingsToMemory(ptr::null_mut())) };
        buf.push_str(&data.to_string_lossy());
    }
    /// Sets the clipboard backend used for clipboard operations
    pub fn set_clipboard_backend<T: ClipboardBackend>(&mut self, backend: T) {
        let clipboard_ctx: Box<UnsafeCell<_>> = Box::new(ClipboardContext::new(backend).into());
        let io = self.io_mut();
        io.set_clipboard_text_fn = Some(crate::clipboard::set_clipboard_text);
        io.get_clipboard_text_fn = Some(crate::clipboard::get_clipboard_text);

        io.clipboard_user_data = clipboard_ctx.get() as *mut _;
        self.clipboard_ctx = clipboard_ctx;
    }
    fn create_internal(shared_font_atlas: Option<Rc<RefCell<SharedFontAtlas>>>) -> Self {
        let _guard = CTX_MUTEX.lock();
        assert!(
            no_current_context(),
            "A new active context cannot be created, because another one already exists"
        );

        let shared_font_atlas_ptr = match &shared_font_atlas {
            Some(shared_font_atlas) => {
                let borrowed_font_atlas = shared_font_atlas.borrow();
                borrowed_font_atlas.0
            }
            None => ptr::null_mut(),
        };
        // Dear ImGui implicitly sets the current context during igCreateContext if the current
        // context doesn't exist
        let raw = unsafe { sys::igCreateContext(shared_font_atlas_ptr) };

        Context {
            raw,
            shared_font_atlas,
            ini_filename: None,
            log_filename: None,
            platform_name: None,
            renderer_name: None,
            clipboard_ctx: Box::new(ClipboardContext::dummy().into()),
        }
    }
    fn is_current_context(&self) -> bool {
        let ctx = unsafe { sys::igGetCurrentContext() };
        self.raw == ctx
    }
}

impl Drop for Context {
    #[doc(alias = "DestroyContext")]
    fn drop(&mut self) {
        let _guard = CTX_MUTEX.lock();
        // If this context is the active context, Dear ImGui automatically deactivates it during
        // destruction
        unsafe {
            sys::igDestroyContext(self.raw);
        }
    }
}

/// A suspended imgui-rs context.
///
/// A suspended context retains its state, but is not usable without activating it first.
///
/// # Examples
///
/// Suspended contexts are not directly very useful, but you can activate them:
///
/// ```
/// let suspended = arcdps_imgui::SuspendedContext::create();
/// match suspended.activate() {
///   Ok(ctx) => {
///     // ctx is now the active context
///   },
///   Err(suspended) => {
///     // activation failed, so you get the suspended context back
///   }
/// }
/// ```
#[derive(Debug)]
pub struct SuspendedContext(Context);

impl SuspendedContext {
    /// Creates a new suspended imgui-rs context.
    #[doc(alias = "CreateContext")]
    pub fn create() -> Self {
        Self::create_internal(None)
    }
    /// Creates a new suspended imgui-rs context with a shared font atlas.
    pub fn create_with_shared_font_atlas(shared_font_atlas: Rc<RefCell<SharedFontAtlas>>) -> Self {
        Self::create_internal(Some(shared_font_atlas))
    }
    /// Attempts to activate this suspended context.
    ///
    /// If there is no active context, this suspended context is activated and `Ok` is returned,
    /// containing the activated context.
    /// If there is already an active context, nothing happens and `Err` is returned, containing
    /// the original suspended context.
    #[doc(alias = "SetCurrentContext")]
    pub fn activate(self) -> Result<Context, SuspendedContext> {
        let _guard = CTX_MUTEX.lock();
        if no_current_context() {
            unsafe {
                sys::igSetCurrentContext(self.0.raw);
            }
            Ok(self.0)
        } else {
            Err(self)
        }
    }
    fn create_internal(shared_font_atlas: Option<Rc<RefCell<SharedFontAtlas>>>) -> Self {
        let _guard = CTX_MUTEX.lock();
        let raw = unsafe { sys::igCreateContext(ptr::null_mut()) };
        let ctx = Context {
            raw,
            shared_font_atlas,
            ini_filename: None,
            log_filename: None,
            platform_name: None,
            renderer_name: None,
            clipboard_ctx: Box::new(ClipboardContext::dummy().into()),
        };
        if ctx.is_current_context() {
            // Oops, the context was activated -> deactivate
            clear_current_context();
        }
        SuspendedContext(ctx)
    }
}

#[test]
fn test_one_context() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let _ctx = Context::create();
    assert!(!no_current_context());
}

#[test]
fn test_drop_clears_current_context() {
    let _guard = crate::test::TEST_MUTEX.lock();
    {
        let _ctx1 = Context::create();
        assert!(!no_current_context());
    }
    assert!(no_current_context());
    {
        let _ctx2 = Context::create();
        assert!(!no_current_context());
    }
    assert!(no_current_context());
}

#[test]
fn test_new_suspended() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let ctx = Context::create();
    let _suspended = SuspendedContext::create();
    assert!(ctx.is_current_context());
    ::std::mem::drop(_suspended);
    assert!(ctx.is_current_context());
}

#[test]
fn test_suspend() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let ctx = Context::create();
    assert!(!no_current_context());
    let _suspended = ctx.suspend();
    assert!(no_current_context());
    let _ctx2 = Context::create();
}

#[test]
fn test_drop_suspended() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let suspended = Context::create().suspend();
    assert!(no_current_context());
    let ctx2 = Context::create();
    ::std::mem::drop(suspended);
    assert!(ctx2.is_current_context());
}

#[test]
fn test_suspend_activate() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let suspended = Context::create().suspend();
    assert!(no_current_context());
    let ctx = suspended.activate().unwrap();
    assert!(ctx.is_current_context());
}

#[test]
fn test_suspend_failure() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let suspended = Context::create().suspend();
    let _ctx = Context::create();
    assert!(suspended.activate().is_err());
}

#[test]
fn test_shared_font_atlas() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let atlas = Rc::new(RefCell::new(SharedFontAtlas::create()));
    let suspended1 = SuspendedContext::create_with_shared_font_atlas(atlas.clone());
    let mut ctx2 = Context::create_with_shared_font_atlas(atlas);
    {
        let _borrow = ctx2.fonts();
    }
    let _suspended2 = ctx2.suspend();
    let mut ctx = suspended1.activate().unwrap();
    let _borrow = ctx.fonts();
}

#[test]
#[should_panic]
fn test_shared_font_atlas_borrow_panic() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let atlas = Rc::new(RefCell::new(SharedFontAtlas::create()));
    let _suspended = SuspendedContext::create_with_shared_font_atlas(atlas.clone());
    let mut ctx = Context::create_with_shared_font_atlas(atlas.clone());
    let _borrow1 = atlas.borrow();
    let _borrow2 = ctx.fonts();
}

#[test]
fn test_ini_load_save() {
    let (_guard, mut ctx) = crate::test::test_ctx();
    let data = "[Window][Debug##Default]
Pos=60,60
Size=400,400
Collapsed=0";
    ctx.load_ini_settings(data);
    let mut buf = String::new();
    ctx.save_ini_settings(&mut buf);
    assert_eq!(data.trim(), buf.trim());
}

#[test]
fn test_default_ini_filename() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let ctx = Context::create();
    assert_eq!(ctx.ini_filename(), Some(PathBuf::from("imgui.ini")));
}

#[test]
fn test_set_ini_filename() {
    let (_guard, mut ctx) = crate::test::test_ctx();
    ctx.set_ini_filename(Some(PathBuf::from("test.ini")));
    assert_eq!(ctx.ini_filename(), Some(PathBuf::from("test.ini")));
}

#[test]
fn test_default_log_filename() {
    let _guard = crate::test::TEST_MUTEX.lock();
    let ctx = Context::create();
    assert_eq!(ctx.log_filename(), Some(PathBuf::from("imgui_log.txt")));
}

#[test]
fn test_set_log_filename() {
    let (_guard, mut ctx) = crate::test::test_ctx();
    ctx.set_log_filename(Some(PathBuf::from("test.log")));
    assert_eq!(ctx.log_filename(), Some(PathBuf::from("test.log")));
}

impl Context {
    /// Returns an immutable reference to the inputs/outputs object
    pub fn io(&self) -> &Io {
        unsafe {
            // safe because Io is a transparent wrapper around sys::ImGuiIO
            &*(sys::igGetIO() as *const Io)
        }
    }
    /// Returns a mutable reference to the inputs/outputs object
    pub fn io_mut(&mut self) -> &mut Io {
        unsafe {
            // safe because Io is a transparent wrapper around sys::ImGuiIO
            &mut *(sys::igGetIO() as *mut Io)
        }
    }
    /// Returns an immutable reference to the user interface style
    #[doc(alias = "GetStyle")]
    pub fn style(&self) -> &Style {
        unsafe {
            // safe because Style is a transparent wrapper around sys::ImGuiStyle
            &*(sys::igGetStyle() as *const Style)
        }
    }
    /// Returns a mutable reference to the user interface style
    #[doc(alias = "GetStyle")]
    pub fn style_mut(&mut self) -> &mut Style {
        unsafe {
            // safe because Style is a transparent wrapper around sys::ImGuiStyle
            &mut *(sys::igGetStyle() as *mut Style)
        }
    }
    /// Returns a mutable reference to the font atlas.
    ///
    /// # Panics
    ///
    /// Panics if the context uses a shared font atlas that is already borrowed
    pub fn fonts(&mut self) -> FontAtlasRefMut<'_> {
        match self.shared_font_atlas {
            Some(ref font_atlas) => FontAtlasRefMut::Shared(font_atlas.borrow_mut()),
            None => unsafe {
                // safe because FontAtlas is a transparent wrapper around sys::ImFontAtlas
                let fonts = &mut *(self.io_mut().fonts as *mut FontAtlas);
                FontAtlasRefMut::Owned(fonts)
            },
        }
    }
    /// Starts a new frame and returns an `Ui` instance for constructing a user interface.
    ///
    /// # Panics
    ///
    /// Panics if the context uses a shared font atlas that is already borrowed
    #[doc(alias = "NewFame")]
    pub fn frame(&mut self) -> Ui<'_> {
        // Clear default font if it no longer exists. This could be an error in the future
        let default_font = self.io().font_default;
        if !default_font.is_null() && self.fonts().get_font(FontId(default_font)).is_none() {
            self.io_mut().font_default = ptr::null_mut();
        }
        // NewFrame/Render/EndFrame mutate the font atlas so we need exclusive access to it
        let font_atlas = self
            .shared_font_atlas
            .as_ref()
            .map(|font_atlas| font_atlas.borrow_mut());
        // TODO: precondition checks
        unsafe {
            sys::igNewFrame();
        }
        Ui {
            ctx: self,
            font_atlas,
            buffer: crate::UiBuffer::new(1024).into(),
        }
    }
}