From 61fb909559bc61e2179f3ea7b62b60e2e7df3ac0 Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Wed, 2 Jan 2019 21:05:37 -0800
Subject: Update src/liballoc/vec.rs

Add @centril's comment

Co-Authored-By: scottmcm <scottmcm@users.noreply.github.com>
---
 src/liballoc/vec.rs | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'src/liballoc')

diff --git a/src/liballoc/vec.rs b/src/liballoc/vec.rs
index b987b94500f..30bcc034221 100644
--- a/src/liballoc/vec.rs
+++ b/src/liballoc/vec.rs
@@ -790,6 +790,10 @@ impl<T> Vec<T> {
     ///     // Per the FFI method's docs, "32768 bytes is always enough".
     ///     let mut dict = Vec::with_capacity(32_768);
     ///     let mut dict_length = 0;
+    ///     // SAFETY: When `deflateGetDictionary` returns `Z_OK`, it holds that:
+    ///     // 1. `dict_length` elements were initialized.
+    ///     // 2. `dict_length` <= the capacity (32_768)
+    ///     // which makes `set_len` safe to call.
     ///     unsafe {
     ///         // Make the FFI call...
     ///         let r = deflateGetDictionary(self.strm, dict.as_mut_ptr(), &mut dict_length);
-- 
cgit 1.4.1-3-g733a5