From b26573b52f1ace32f27232276eb0aadd1d0b0640 Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy@goop.org>
Date: Wed, 22 Feb 2023 09:55:01 -0800
Subject: [PATCH] Implement `.populate()` for `map_anon()`.

Closes #70
---
 src/lib.rs     | 2 +-
 src/stub.rs    | 2 +-
 src/unix.rs    | 5 +++--
 src/windows.rs | 2 +-
 4 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 0d64d2b6..2d730ae9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -482,7 +482,7 @@ impl MmapOptions {
             ));
         }
 
-        MmapInner::map_anon(len, self.stack).map(|inner| MmapMut { inner })
+        MmapInner::map_anon(len, self.stack, self.populate).map(|inner| MmapMut { inner })
     }
 
     /// Creates a raw memory map.
diff --git a/src/stub.rs b/src/stub.rs
index e756da4f..3c6af0e7 100644
--- a/src/stub.rs
+++ b/src/stub.rs
@@ -36,7 +36,7 @@ impl MmapInner {
         MmapInner::new()
     }
 
-    pub fn map_anon(_: usize, _: bool) -> io::Result<MmapInner> {
+    pub fn map_anon(_: usize, _: bool, _: bool) -> io::Result<MmapInner> {
         MmapInner::new()
     }
 
diff --git a/src/unix.rs b/src/unix.rs
index f691e680..221d3ba8 100644
--- a/src/unix.rs
+++ b/src/unix.rs
@@ -162,12 +162,13 @@ impl MmapInner {
     }
 
     /// Open an anonymous memory map.
-    pub fn map_anon(len: usize, stack: bool) -> io::Result<MmapInner> {
+    pub fn map_anon(len: usize, stack: bool, populate: bool) -> io::Result<MmapInner> {
         let stack = if stack { MAP_STACK } else { 0 };
+        let populate = if populate { MAP_POPULATE } else { 0 };
         MmapInner::new(
             len,
             libc::PROT_READ | libc::PROT_WRITE,
-            libc::MAP_PRIVATE | libc::MAP_ANON | stack,
+            libc::MAP_PRIVATE | libc::MAP_ANON | stack | populate,
             -1,
             0,
         )
diff --git a/src/windows.rs b/src/windows.rs
index d580995e..c1b1a4d9 100644
--- a/src/windows.rs
+++ b/src/windows.rs
@@ -340,7 +340,7 @@ impl MmapInner {
         Ok(inner)
     }
 
-    pub fn map_anon(len: usize, _stack: bool) -> io::Result<MmapInner> {
+    pub fn map_anon(len: usize, _stack: bool, _populate: bool) -> io::Result<MmapInner> {
         // Ensure a non-zero length for the underlying mapping
         let mapped_len = len.max(1);
         unsafe {