From a87395423915f913b819291b3b4920501cccdf95 Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Mon, 19 Oct 2020 12:15:55 +0200
Subject: Gracefully handle puglRealize() being called twice

---
 pugl/detail/mac.m   |   6 +++-
 pugl/detail/win.c   |   3 ++
 pugl/detail/x11.c   |   6 +++-
 test/test_realize.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 wscript             |   1 +
 5 files changed, 114 insertions(+), 2 deletions(-)
 create mode 100644 test/test_realize.c

diff --git a/pugl/detail/mac.m b/pugl/detail/mac.m
index 5f7e126..8faee86 100644
--- a/pugl/detail/mac.m
+++ b/pugl/detail/mac.m
@@ -868,7 +868,11 @@ puglConstraint(id item, NSLayoutAttribute attribute, float constant)
 PuglStatus
 puglRealize(PuglView* view)
 {
-	PuglInternals*        impl        = view->impl;
+	PuglInternals* impl = view->impl;
+	if (impl->wrapperView) {
+		return PUGL_FAILURE;
+	}
+
 	const NSScreen* const screen      = [NSScreen mainScreen];
 	const double          scaleFactor = [screen backingScaleFactor];
 
diff --git a/pugl/detail/win.c b/pugl/detail/win.c
index b29ccf4..b3ba00d 100644
--- a/pugl/detail/win.c
+++ b/pugl/detail/win.c
@@ -165,6 +165,9 @@ PuglStatus
 puglRealize(PuglView* view)
 {
 	PuglInternals* impl = view->impl;
+	if (impl->hwnd) {
+		return PUGL_FAILURE;
+	}
 
 	// Getting depth from the display mode seems tedious, just set usual values
 	if (view->hints[PUGL_RED_BITS] == PUGL_DONT_CARE) {
diff --git a/pugl/detail/x11.c b/pugl/detail/x11.c
index f9a45e8..e6444c8 100644
--- a/pugl/detail/x11.c
+++ b/pugl/detail/x11.c
@@ -278,7 +278,11 @@ puglDefineCursorShape(PuglView* view, unsigned shape)
 PuglStatus
 puglRealize(PuglView* view)
 {
-	PuglInternals* const impl    = view->impl;
+	PuglInternals* const impl = view->impl;
+	if (impl->win) {
+		return PUGL_FAILURE;
+	}
+
 	PuglWorld* const     world   = view->world;
 	PuglX11Atoms* const  atoms   = &view->world->impl->atoms;
 	Display* const       display = world->impl->display;
diff --git a/test/test_realize.c b/test/test_realize.c
new file mode 100644
index 0000000..4a12d1d
--- /dev/null
+++ b/test/test_realize.c
@@ -0,0 +1,100 @@
+/*
+  Copyright 2020 David Robillard <d@drobilla.net>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+/*
+  Tests that realize sends a create event, and can safely be called twice.
+
+  Without handling this case, an application that accidentally calls realize
+  twice could end up in a very confusing situation where multiple windows have
+  been allocated (and ultimately leaked) for a view.
+*/
+
+#undef NDEBUG
+
+#include "test_utils.h"
+
+#include "pugl/pugl.h"
+#include "pugl/pugl_stub.h"
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+typedef enum {
+	START,
+	CREATED,
+} State;
+
+typedef struct {
+	PuglWorld*      world;
+	PuglView*       view;
+	PuglTestOptions opts;
+	State           state;
+} PuglTest;
+
+static PuglStatus
+onEvent(PuglView* view, const PuglEvent* event)
+{
+	PuglTest* test = (PuglTest*)puglGetHandle(view);
+
+	if (test->opts.verbose) {
+		printEvent(event, "Event: ", true);
+	}
+
+	switch (event->type) {
+	case PUGL_CREATE:
+		assert(test->state == START);
+		test->state = CREATED;
+		break;
+	default:
+		break;
+	}
+
+	return PUGL_SUCCESS;
+}
+
+int
+main(int argc, char** argv)
+{
+	PuglTest test = {puglNewWorld(PUGL_PROGRAM, 0),
+	                 NULL,
+	                 puglParseTestOptions(&argc, &argv),
+	                 START};
+
+	// Set up view
+	test.view = puglNewView(test.world);
+	puglSetClassName(test.world, "Pugl Test");
+	puglSetBackend(test.view, puglStubBackend());
+	puglSetHandle(test.view, &test);
+	puglSetEventFunc(test.view, onEvent);
+	puglSetDefaultSize(test.view, 512, 512);
+
+	// Create initially invisible window
+	assert(!puglRealize(test.view));
+	assert(!puglGetVisible(test.view));
+	while (test.state < CREATED) {
+		assert(!puglUpdate(test.world, -1.0));
+	}
+
+	// Check that calling realize() again is okay
+	assert(puglRealize(test.view) == PUGL_FAILURE);
+
+	// Tear down
+	puglFreeView(test.view);
+	puglFreeWorld(test.world);
+
+	return 0;
+}
diff --git a/wscript b/wscript
index 525c929..554a2e1 100644
--- a/wscript
+++ b/wscript
@@ -269,6 +269,7 @@ def _build_pc_file(bld, name, desc, target, libname, deps={}, requires=[]):
 gl_tests = ['gl_hints']
 
 basic_tests = [
+    'realize',
     'redisplay',
     'show_hide',
     'stub_hints',
-- 
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