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// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
extern crate flexbuffers;
use flexbuffers::*;
use std::alloc::{GlobalAlloc, Layout, System};
/// We take over the Rust allocator to count allocations. This is super not thread safe.
static mut NUM_ALLOCS: usize = 0;
fn current_allocs() -> usize {
unsafe { NUM_ALLOCS }
}
struct TrackingAllocator;
unsafe impl GlobalAlloc for TrackingAllocator {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
NUM_ALLOCS += 1;
System.alloc(layout)
}
unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
System.dealloc(ptr, layout)
}
}
#[global_allocator]
static T: TrackingAllocator = TrackingAllocator;
/// Make some example data
fn make_monster(mut monster: MapBuilder) {
monster.push("type", "great orc");
monster.push("age", 100u8);
monster.push("name", "Mr. Orc");
monster.push("coins", &[1, 25, 50, 100, 250]);
monster.push("color", &[255u8, 0, 0, 0]);
{
let mut weapons = monster.start_vector("weapons");
{
let mut hammer = weapons.start_map();
hammer.push("name", "hammer");
hammer.push("damage type", "crush");
hammer.push("damage", 20);
}
{
let mut axe = weapons.start_map();
axe.push("name", "Great Axe");
axe.push("damage type", "slash");
axe.push("damage", 30);
}
}
{
let mut sounds = monster.start_vector("sounds");
sounds.push("grr");
sounds.push("rawr");
sounds.push("muahaha");
}
// TODO(cneo): Directly pushing string slices has alloc.
}
// Read back the data from make_monster.
fn validate_monster(flexbuffer: &[u8]) {
let r = Reader::get_root(flexbuffer).unwrap().as_map();
assert!(!r.is_empty());
assert!(r.index_key("not_a_field").is_none());
assert_eq!(r.len(), 7);
assert_eq!(r.idx("type").as_str(), "great orc");
assert_eq!(r.idx("age").as_u8(), 100);
assert_eq!(r.idx("name").as_str(), "Mr. Orc");
let coins = r.idx("coins").as_vector();
for (i, &c) in [1, 25, 50, 100, 250].iter().enumerate() {
assert_eq!(coins.idx(i).as_u16(), c);
}
let color = r.idx("color").as_vector();
for (i, &c) in [255, 0, 0, 0].iter().enumerate() {
assert_eq!(color.idx(i).as_i32(), c);
}
let weapons = r.idx("weapons").as_vector();
assert_eq!(weapons.len(), 2);
let hammer = weapons.idx(0).as_map();
assert_eq!(hammer.idx("name").as_str(), "hammer");
assert_eq!(hammer.idx("damage type").as_str(), "crush");
assert_eq!(hammer.idx("damage").as_u64(), 20);
let axe = weapons.idx(1).as_map();
assert_eq!(axe.idx("name").as_str(), "Great Axe");
assert_eq!(axe.idx("damage type").as_str(), "slash");
assert_eq!(axe.idx("damage").as_u64(), 30);
let sounds = r.idx("sounds").as_vector();
for (i, &s) in ["grr", "rawr", "muahaha"].iter().enumerate() {
assert_eq!(sounds.idx(i).as_str(), s);
}
}
// This is in a separate binary than tests because taking over the global allocator is not
// hermetic and not thread safe.
#[cfg(not(miri))] // slow.
fn main() {
let start_up = current_allocs();
// Let's build a flexbuffer from a new (cold) flexbuffer builder.
let mut builder = Builder::default();
make_monster(builder.start_map());
let after_warmup = current_allocs();
// The builder makes some allocations while warming up.
assert!(after_warmup > start_up);
assert!(after_warmup < start_up + 20);
// A warm builder should make no allocations.
make_monster(builder.start_map());
assert_eq!(after_warmup, current_allocs());
// Nor should a reader.
validate_monster(builder.view());
assert_eq!(after_warmup, current_allocs());
// Do it again just for kicks.
make_monster(builder.start_map());
validate_monster(builder.view());
assert_eq!(after_warmup, current_allocs());
let final_allocs = current_allocs(); // dbg! does allocate.
dbg!(start_up, after_warmup, final_allocs);
}
#[test]
#[cfg(not(miri))] // slow.
fn no_extra_allocations() {
main()
}
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