From 77370a01ead42ecb40decd003e1a181f1a892abe Mon Sep 17 00:00:00 2001
From: Duy Tran Khanh <khanhduytran0@users.noreply.github.com>
Date: Fri, 16 Sep 2022 17:43:53 +0700
Subject: [PATCH] Self-controlled Jetsam limit for unsandboxed env

---
 Natives/SurfaceViewController.m | 17 +++++++++++++++++
 entitlements.xml                |  4 ++++
 entitlements_ipa.xml            |  4 ++++
 3 files changed, 25 insertions(+)

diff --git a/Natives/SurfaceViewController.m b/Natives/SurfaceViewController.m
index 1d9fbf7b..1b5d582b 100644
--- a/Natives/SurfaceViewController.m
+++ b/Natives/SurfaceViewController.m
@@ -21,6 +21,9 @@
 #include "glfw_keycodes.h"
 #include "utils.h"
 
+int memorystatus_control(uint32_t command, int32_t pid, uint32_t flags, void *buffer, size_t buffersize);
+#define MEMORYSTATUS_CMD_SET_JETSAM_TASK_LIMIT        6
+
 // Debugging only
 // #define DEBUG_VISIBLE_TEXT_FIELD
 // #define DEBUG_VISIBLE_TOUCH
@@ -401,11 +404,25 @@ self.view.frame.size.width * 0.3 - 36.0 * 0.7, self.view.frame.size.height)];
 */
 
     // [self setPreferredFramesPerSecond:1000];
+    [self updateJetsamControl];
     [self updatePreferenceChanges];
     [self executebtn_special_togglebtn:0];
     [self launchMinecraft];
 }
 
+- (void)updateJetsamControl {
+    if (!getEntitlementValue(@"com.apple.private.memorystatus")) {
+        return;
+    }
+    // More 1024MB is necessary for other memory regions (native, Java GC, etc.)
+    int limit = [getPreference(@"allocated_memory") intValue] + 1024;
+    if (memorystatus_control(MEMORYSTATUS_CMD_SET_JETSAM_TASK_LIMIT, getpid(), limit, NULL, 0) == -1) {
+        NSLog(@"Failed to set Jetsam task limit: error: %s", strerror(errno));
+    } else {
+        NSLog(@"Successfully set Jetsam task limit");
+    }
+}
+
 - (void)updatePreferenceChanges {
     self.mouseSpeed = [getPreference(@"mouse_speed") floatValue] / 100.0;
     slideableHotbar = [getPreference(@"slideable_hotbar") boolValue];
diff --git a/entitlements.xml b/entitlements.xml
index 0f64cd0b..c6d527b8 100644
--- a/entitlements.xml
+++ b/entitlements.xml
@@ -19,5 +19,9 @@
     <true/>
     <key>dynamic-codesigning</key>
     <true/>
+
+    <!-- Give ability to change Jetsam task limit by itself -->
+    <key>com.apple.private.memorystatus</key>
+    <true/>
 </dict>
 </plist>
diff --git a/entitlements_ipa.xml b/entitlements_ipa.xml
index 66e11cbd..217ba4f1 100644
--- a/entitlements_ipa.xml
+++ b/entitlements_ipa.xml
@@ -13,6 +13,10 @@
     <key>com.apple.private.mobileinstall.upgrade-enabled</key>
     <true/>
 
+    <!-- Give ability to change Jetsam task limit by itself -->
+    <key>com.apple.private.memorystatus</key>
+    <true/>
+
     <!-- Disable sandbox so that PojavLauncher can enable JIT by itself -->
     <key>com.apple.private.security.no-container</key>
     <true/>