From 92bfcd2b192e59d12d64acf6f46c1897a3273b3e Mon Sep 17 00:00:00 2001 From: snf Date: Thu, 8 Mar 2018 14:36:43 +0000 Subject: implementing fallible allocation API (try_reserve) for Vec, String and HashMap --- src/liballoc/tests/string.rs | 163 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 163 insertions(+) (limited to 'src/liballoc/tests/string.rs') diff --git a/src/liballoc/tests/string.rs b/src/liballoc/tests/string.rs index ef6f5e10a72..d1e746ea43b 100644 --- a/src/liballoc/tests/string.rs +++ b/src/liballoc/tests/string.rs @@ -9,6 +9,9 @@ // except according to those terms. use std::borrow::Cow; +use std::collections::CollectionAllocErr::*; +use std::mem::size_of; +use std::{usize, isize}; pub trait IntoCow<'a, B: ?Sized> where B: ToOwned { fn into_cow(self) -> Cow<'a, B>; @@ -504,3 +507,163 @@ fn test_into_boxed_str() { let ys = xs.into_boxed_str(); assert_eq!(&*ys, "hello my name is bob"); } + +#[test] +fn test_reserve_exact() { + // This is all the same as test_reserve + + let mut s = String::new(); + assert_eq!(s.capacity(), 0); + + s.reserve_exact(2); + assert!(s.capacity() >= 2); + + for _i in 0..16 { + s.push('0'); + } + + assert!(s.capacity() >= 16); + s.reserve_exact(16); + assert!(s.capacity() >= 32); + + s.push('0'); + + s.reserve_exact(16); + assert!(s.capacity() >= 33) +} + +#[test] +fn test_try_reserve() { + + // These are the interesting cases: + // * exactly isize::MAX should never trigger a CapacityOverflow (can be OOM) + // * > isize::MAX should always fail + // * On 16/32-bit should CapacityOverflow + // * On 64-bit should OOM + // * overflow may trigger when adding `len` to `cap` (in number of elements) + // * overflow may trigger when multiplying `new_cap` by size_of:: (to get bytes) + + const MAX_CAP: usize = isize::MAX as usize; + const MAX_USIZE: usize = usize::MAX; + + // On 16/32-bit, we check that allocations don't exceed isize::MAX, + // on 64-bit, we assume the OS will give an OOM for such a ridiculous size. + // Any platform that succeeds for these requests is technically broken with + // ptr::offset because LLVM is the worst. + let guards_against_isize = size_of::() < 8; + + { + // Note: basic stuff is checked by test_reserve + let mut empty_string: String = String::new(); + + // Check isize::MAX doesn't count as an overflow + if let Err(CapacityOverflow) = empty_string.try_reserve(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + // Play it again, frank! (just to be sure) + if let Err(CapacityOverflow) = empty_string.try_reserve(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + + if guards_against_isize { + // Check isize::MAX + 1 does count as overflow + if let Err(CapacityOverflow) = empty_string.try_reserve(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an overflow!") } + + // Check usize::MAX does count as overflow + if let Err(CapacityOverflow) = empty_string.try_reserve(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } else { + // Check isize::MAX + 1 is an OOM + if let Err(AllocErr(_)) = empty_string.try_reserve(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + + // Check usize::MAX is an OOM + if let Err(AllocErr(_)) = empty_string.try_reserve(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an OOM!") } + } + } + + + { + // Same basic idea, but with non-zero len + let mut ten_bytes: String = String::from("0123456789"); + + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if guards_against_isize { + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an overflow!"); } + } else { + if let Err(AllocErr(_)) = ten_bytes.try_reserve(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + } + // Should always overflow in the add-to-len + if let Err(CapacityOverflow) = ten_bytes.try_reserve(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } + +} + +#[test] +fn test_try_reserve_exact() { + + // This is exactly the same as test_try_reserve with the method changed. + // See that test for comments. + + const MAX_CAP: usize = isize::MAX as usize; + const MAX_USIZE: usize = usize::MAX; + + let guards_against_isize = size_of::() < 8; + + { + let mut empty_string: String = String::new(); + + if let Err(CapacityOverflow) = empty_string.try_reserve_exact(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = empty_string.try_reserve_exact(MAX_CAP) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + + if guards_against_isize { + if let Err(CapacityOverflow) = empty_string.try_reserve_exact(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an overflow!") } + + if let Err(CapacityOverflow) = empty_string.try_reserve_exact(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } else { + if let Err(AllocErr(_)) = empty_string.try_reserve_exact(MAX_CAP + 1) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + + if let Err(AllocErr(_)) = empty_string.try_reserve_exact(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an OOM!") } + } + } + + + { + let mut ten_bytes: String = String::from("0123456789"); + + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 10) { + panic!("isize::MAX shouldn't trigger an overflow!"); + } + if guards_against_isize { + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an overflow!"); } + } else { + if let Err(AllocErr(_)) = ten_bytes.try_reserve_exact(MAX_CAP - 9) { + } else { panic!("isize::MAX + 1 should trigger an OOM!") } + } + if let Err(CapacityOverflow) = ten_bytes.try_reserve_exact(MAX_USIZE) { + } else { panic!("usize::MAX should trigger an overflow!") } + } + +} -- cgit 1.4.1-3-g733a5