Update ID stack manipulation to use stack tokens

CHANGELOG.markdown

@@ -17,6 +17,7 @@
 - Glium renderer re-exports imgui and glium
 - Gfx renderer re-exports imgui and gfx
 - These functions now take/return PathBuf: log_filename, set_log_filename, ini_filename, set_logfilename
+- ID stack manipulation now uses stack tokens
 
 ### Removed
 

src/legacy.rs

@@ -6,7 +6,7 @@ use crate::string::ImStr;
 use crate::widget::color_editors::*;
 use crate::widget::progress_bar::ProgressBar;
 use crate::window::{Window, WindowFlags};
-use crate::Ui;
+use crate::{Id, Ui};
 
 #[deprecated(since = "0.2.0", note = "use ColorEditFlags instead")]
 pub type ImGuiColorEditFlags = ColorEditFlags;
@@ -370,3 +370,15 @@ impl<'ui> Ui<'ui> {
         unsafe { sys::igGetColumnsCount() }
     }
 }
+
+impl<'ui> Ui<'ui> {
+    #[deprecated(since = "0.2.0", note = "use Ui::push_id instead")]
+    pub fn with_id<'a, F, I>(&self, id: I, f: F)
+    where
+        F: FnOnce(),
+        I: Into<Id<'a>>,
+    {
+        let _token = self.push_id(id);
+        f();
+    }
+}

src/lib.rs

@@ -205,76 +205,35 @@ impl<'ui> Ui<'ui> {
     }
 }
 
-pub enum ImId<'a> {
+/// Unique ID used by widgets
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum Id<'a> {
     Int(i32),
     Str(&'a str),
     Ptr(*const c_void),
 }
 
-impl From<i32> for ImId<'static> {
+impl From<i32> for Id<'static> {
     fn from(i: i32) -> Self {
-        ImId::Int(i)
+        Id::Int(i)
     }
 }
 
-impl<'a, T: ?Sized + AsRef<str>> From<&'a T> for ImId<'a> {
+impl<'a, T: ?Sized + AsRef<str>> From<&'a T> for Id<'a> {
     fn from(s: &'a T) -> Self {
-        ImId::Str(s.as_ref())
+        Id::Str(s.as_ref())
     }
 }
 
-impl<T> From<*const T> for ImId<'static> {
+impl<T> From<*const T> for Id<'static> {
     fn from(p: *const T) -> Self {
-        ImId::Ptr(p as *const c_void)
+        Id::Ptr(p as *const c_void)
     }
 }
 
-impl<T> From<*mut T> for ImId<'static> {
+impl<T> From<*mut T> for Id<'static> {
     fn from(p: *mut T) -> Self {
-        ImId::Ptr(p as *const T as *const c_void)
+        Id::Ptr(p as *const T as *const c_void)
-    }
-}
-
-// ID scopes
-impl<'ui> Ui<'ui> {
-    /// Pushes an identifier to the ID stack.
-    pub fn push_id<'a, I: Into<ImId<'a>>>(&self, id: I) {
-        let id = id.into();
-
-        unsafe {
-            match id {
-                ImId::Int(i) => {
-                    sys::igPushIDInt(i);
-                }
-                ImId::Str(s) => {
-                    let start = s.as_ptr() as *const c_char;
-                    let end = start.add(s.len());
-                    sys::igPushIDRange(start, end);
-                }
-                ImId::Ptr(p) => {
-                    sys::igPushIDPtr(p as *const c_void);
-                }
-            }
-        }
-    }
-
-    /// Pops an identifier from the ID stack.
-    ///
-    /// # Aborts
-    /// The current process is aborted if the ID stack is empty.
-    pub fn pop_id(&self) {
-        unsafe { sys::igPopID() };
-    }
-
-    /// Runs a function after temporarily pushing a value to the ID stack.
-    pub fn with_id<'a, F, I>(&self, id: I, f: F)
-    where
-        F: FnOnce(),
-        I: Into<ImId<'a>>,
-    {
-        self.push_id(id);
-        f();
-        self.pop_id();
     }
 }
 

src/stacks.rs

@@ -1,11 +1,12 @@
 use std::marker::PhantomData;
 use std::mem;
+use std::os::raw::{c_char, c_void};
 
 use crate::fonts::atlas::FontId;
 use crate::internal::RawCast;
 use crate::style::{StyleColor, StyleVar};
 use crate::sys;
-use crate::Ui;
+use crate::{Id, Ui};
 
 /// # Parameter stacks (shared)
 impl<'ui> Ui<'ui> {
@@ -301,3 +302,36 @@ impl<'ui> Drop for ItemFlagsStackToken<'ui> {
         }
     }
 }
+
+/// # ID stack
+impl<'ui> Ui<'ui> {
+    /// Pushes an identifier to the ID stack
+    #[must_use]
+    pub fn push_id<'a, I: Into<Id<'a>>>(&self, id: I) -> IdStackToken {
+        let id = id.into();
+
+        unsafe {
+            match id {
+                Id::Int(i) => sys::igPushIDInt(i),
+                Id::Str(s) => {
+                    let start = s.as_ptr() as *const c_char;
+                    let end = start.add(s.len());
+                    sys::igPushIDRange(start, end)
+                }
+                Id::Ptr(p) => sys::igPushIDPtr(p as *const c_void),
+            }
+        }
+        IdStackToken { _ui: PhantomData }
+    }
+}
+
+/// Represents a change pushed to the ID stack
+pub struct IdStackToken<'ui> {
+    _ui: PhantomData<&'ui Ui<'ui>>,
+}
+
+impl<'ui> Drop for IdStackToken<'ui> {
+    fn drop(&mut self) {
+        unsafe { sys::igPopID() };
+    }
+}