From 4faab8842cab50b18f87b4a8381a476646b8e680 Mon Sep 17 00:00:00 2001
From: Stefan Siegl <stesie@brokenpipe.de>
Date: Sat, 26 Mar 2016 00:37:53 +0100
Subject: [PATCH 1/4] Re-check memory limit, refs #217

---
 v8js_v8.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/v8js_v8.cc b/v8js_v8.cc
index 8091429..0b4b766 100644
--- a/v8js_v8.cc
+++ b/v8js_v8.cc
@@ -204,6 +204,16 @@ void v8js_v8_call(v8js_ctx *c, zval **return_value,
 		return;
 	}
 
+	if (memory_limit && !c->memory_limit_hit) {
+		// Re-check memory limit (very short executions might never be hit by timer thread)
+		v8::HeapStatistics hs;
+		isolate->GetHeapStatistics(&hs);
+
+		if (hs.used_heap_size() > memory_limit) {
+			c->memory_limit_hit = true;
+		}
+	}
+
 	if (c->memory_limit_hit) {
 		// Execution has been terminated due to memory limit
 		sprintf(exception_string, "Script memory limit of %lu bytes exceeded", memory_limit);

From b2eb89e49e0ca30cfe561633f361dae652cca55e Mon Sep 17 00:00:00 2001
From: Stefan Siegl <stesie@brokenpipe.de>
Date: Sat, 26 Mar 2016 00:53:52 +0100
Subject: [PATCH 2/4] send LowMemoryNotification before imposing memory limit,
 fixes #217

---
 v8js_timer.cc | 49 ++++++++++++++++++++++++++++++++-----------------
 v8js_v8.cc    |  7 ++++++-
 2 files changed, 38 insertions(+), 18 deletions(-)

diff --git a/v8js_timer.cc b/v8js_timer.cc
index d556716..36c9f81 100644
--- a/v8js_timer.cc
+++ b/v8js_timer.cc
@@ -40,27 +40,42 @@ static void v8js_timer_interrupt_handler(v8::Isolate *isolate, void *data) { /*
 
 	v8::Locker locker(isolate);
 	v8::HeapStatistics hs;
-	isolate->GetHeapStatistics(&hs);
+	bool send_notification, has_sent_notification;
 
-	V8JSG(timer_mutex).lock();
-
-	for (std::deque< v8js_timer_ctx* >::iterator it = V8JSG(timer_stack).begin();
-		 it != V8JSG(timer_stack).end(); it ++) {
-		v8js_timer_ctx *timer_ctx = *it;
-		v8js_ctx *c = timer_ctx->ctx;
-
-		if(c->isolate != isolate || timer_ctx->killed) {
-			continue;
+	do {
+		if (send_notification) {
+			isolate->LowMemoryNotification();
+			has_sent_notification = true;
 		}
 
-		if (timer_ctx->memory_limit > 0 && hs.used_heap_size() > timer_ctx->memory_limit) {
-			timer_ctx->killed = true;
-			v8::V8::TerminateExecution(c->isolate);
-			c->memory_limit_hit = true;
-		}
-	}
+		isolate->GetHeapStatistics(&hs);
 
-	V8JSG(timer_mutex).unlock();
+		V8JSG(timer_mutex).lock();
+
+		for (std::deque< v8js_timer_ctx* >::iterator it = V8JSG(timer_stack).begin();
+			 it != V8JSG(timer_stack).end(); it ++) {
+			v8js_timer_ctx *timer_ctx = *it;
+			v8js_ctx *c = timer_ctx->ctx;
+
+			if(c->isolate != isolate || timer_ctx->killed) {
+				continue;
+			}
+
+			if (timer_ctx->memory_limit > 0 && hs.used_heap_size() > timer_ctx->memory_limit) {
+				if (has_sent_notification) {
+					timer_ctx->killed = true;
+					v8::V8::TerminateExecution(c->isolate);
+					c->memory_limit_hit = true;
+				} else {
+					// force garbage collection, then check again
+					send_notification = true;
+					break;
+				}
+			}
+		}
+
+		V8JSG(timer_mutex).unlock();
+	} while(send_notification != has_sent_notification);
 }
 /* }}} */
 
diff --git a/v8js_v8.cc b/v8js_v8.cc
index 0b4b766..1ab13ab 100644
--- a/v8js_v8.cc
+++ b/v8js_v8.cc
@@ -210,7 +210,12 @@ void v8js_v8_call(v8js_ctx *c, zval **return_value,
 		isolate->GetHeapStatistics(&hs);
 
 		if (hs.used_heap_size() > memory_limit) {
-			c->memory_limit_hit = true;
+			isolate->LowMemoryNotification();
+			isolate->GetHeapStatistics(&hs);
+
+			if (hs.used_heap_size() > memory_limit) {
+				c->memory_limit_hit = true;
+			}
 		}
 	}
 

From 97ade17ef9aa038192004c6b7986eda1139fd98c Mon Sep 17 00:00:00 2001
From: Stefan Siegl <stesie@brokenpipe.de>
Date: Sat, 26 Mar 2016 12:10:32 +0100
Subject: [PATCH 3/4] fix: initialize variables

---
 v8js_timer.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/v8js_timer.cc b/v8js_timer.cc
index 36c9f81..a3ae679 100644
--- a/v8js_timer.cc
+++ b/v8js_timer.cc
@@ -40,7 +40,8 @@ static void v8js_timer_interrupt_handler(v8::Isolate *isolate, void *data) { /*
 
 	v8::Locker locker(isolate);
 	v8::HeapStatistics hs;
-	bool send_notification, has_sent_notification;
+	bool send_notification = false;
+	bool has_sent_notification = false;
 
 	do {
 		if (send_notification) {

From 3dca462e9d0279f0dedbb0fb8e20f761f64465e4 Mon Sep 17 00:00:00 2001
From: Stefan Siegl <stesie@brokenpipe.de>
Date: Sat, 26 Mar 2016 14:11:20 +0100
Subject: [PATCH 4/4] Use V8::LowMemoryNotification on V8 < 3.28.36

---
 v8js_timer.cc | 4 ++++
 v8js_v8.cc    | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/v8js_timer.cc b/v8js_timer.cc
index a3ae679..cb678f1 100644
--- a/v8js_timer.cc
+++ b/v8js_timer.cc
@@ -45,7 +45,11 @@ static void v8js_timer_interrupt_handler(v8::Isolate *isolate, void *data) { /*
 
 	do {
 		if (send_notification) {
+#if PHP_V8_API_VERSION >= 3028036
 			isolate->LowMemoryNotification();
+#else
+			v8::V8::LowMemoryNotification();
+#endif
 			has_sent_notification = true;
 		}
 
diff --git a/v8js_v8.cc b/v8js_v8.cc
index 1ab13ab..8d53665 100644
--- a/v8js_v8.cc
+++ b/v8js_v8.cc
@@ -210,7 +210,11 @@ void v8js_v8_call(v8js_ctx *c, zval **return_value,
 		isolate->GetHeapStatistics(&hs);
 
 		if (hs.used_heap_size() > memory_limit) {
+#if PHP_V8_API_VERSION >= 3028036
 			isolate->LowMemoryNotification();
+#else
+			v8::V8::LowMemoryNotification();
+#endif
 			isolate->GetHeapStatistics(&hs);
 
 			if (hs.used_heap_size() > memory_limit) {