- Currently supports JSON patch operations (add/remove/replace/copy/move/test)
- `GenerateHierarchicalDeltaPatch` provides a patch generation mechanism that produces forward and inverse patches
- Patch application comes with a `PatchApplicationStrategy` functor that allows customizing behavior for patch failure that may be useful for the prefab system
- Serialization to/from JSON patch by way of `AZ::Dom::Value` is supported
Benchmarks provided, split into three categories on the Dom value benchmark payload (payloads with up to 10k entries populated with strings up to 100 characters in length):
- Patch generation based on a deep copy of the affected data
```
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_DeepCopy/10/5 0.024 ms 0.024 ms 29867 items_per_second=41.5541k/s
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_DeepCopy/10/500 0.024 ms 0.024 ms 29867 items_per_second=41.5541k/s
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_DeepCopy/100/5 0.346 ms 0.345 ms 2036 items_per_second=2.89564k/s
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_DeepCopy/100/500 0.375 ms 0.377 ms 1867 items_per_second=2.65529k/s
DomPatchBenchmark/AzDomPatch_Generate_TopLevelReplace/10/5 0.003 ms 0.003 ms 203636 items_per_second=289.616k/s
DomPatchBenchmark/AzDomPatch_Generate_TopLevelReplace/10/500 0.004 ms 0.004 ms 194783 items_per_second=283.321k/s
DomPatchBenchmark/AzDomPatch_Generate_TopLevelReplace/100/5 0.003 ms 0.003 ms 203636 items_per_second=289.616k/s
DomPatchBenchmark/AzDomPatch_Generate_TopLevelReplace/100/500 0.004 ms 0.004 ms 194783 items_per_second=271.002k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_DeepCopy/10/5 0.023 ms 0.024 ms 29867 items_per_second=42.4775k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_DeepCopy/10/500 0.023 ms 0.023 ms 28000 items_per_second=42.6667k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_DeepCopy/100/5 0.341 ms 0.337 ms 2133 items_per_second=2.96765k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_DeepCopy/100/500 0.365 ms 0.361 ms 1948 items_per_second=2.77049k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_DeepCopy/10/5 0.023 ms 0.023 ms 29867 items_per_second=43.4429k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_DeepCopy/10/500 0.023 ms 0.024 ms 29867 items_per_second=42.4775k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_DeepCopy/100/5 0.330 ms 0.330 ms 2133 items_per_second=3.0336k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_DeepCopy/100/500 0.359 ms 0.360 ms 1867 items_per_second=2.77879k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_DeepCopy/10/5 0.023 ms 0.022 ms 29867 items_per_second=44.4532k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_DeepCopy/10/500 0.023 ms 0.023 ms 32000 items_per_second=43.5745k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_DeepCopy/100/5 0.329 ms 0.330 ms 2133 items_per_second=3.0336k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_DeepCopy/100/500 0.357 ms 0.361 ms 1948 items_per_second=2.77049k/s
```
- Patch generation based on a shallow copy of the affected data (this is faster because when using Dom::Value to copy and mutate, we can bypass expensive array and object comparisons for identical values)
```
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_ShallowCopy/10/5 0.010 ms 0.010 ms 74667 items_per_second=99.556k/s
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_ShallowCopy/10/500 0.010 ms 0.010 ms 74667 items_per_second=97.5242k/s
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_ShallowCopy/100/5 0.079 ms 0.078 ms 8960 items_per_second=12.7431k/s
DomPatchBenchmark/AzDomPatch_Generate_SimpleReplace_ShallowCopy/100/500 0.087 ms 0.087 ms 8960 items_per_second=11.4688k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_ShallowCopy/10/5 0.009 ms 0.009 ms 74667 items_per_second=116.553k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_ShallowCopy/10/500 0.009 ms 0.009 ms 74667 items_per_second=113.778k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_ShallowCopy/100/5 0.072 ms 0.071 ms 8960 items_per_second=13.9863k/s
DomPatchBenchmark/AzDomPatch_Generate_KeyRemove_ShallowCopy/100/500 0.087 ms 0.088 ms 7467 items_per_second=11.3783k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_ShallowCopy/10/5 0.014 ms 0.014 ms 49778 items_per_second=72.4044k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_ShallowCopy/10/500 0.014 ms 0.014 ms 56000 items_per_second=70.2745k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_ShallowCopy/100/5 0.118 ms 0.117 ms 5600 items_per_second=8.53333k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayAppend_ShallowCopy/100/500 0.140 ms 0.141 ms 4978 items_per_second=7.07982k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_ShallowCopy/10/5 0.009 ms 0.009 ms 89600 items_per_second=108.196k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_ShallowCopy/10/500 0.009 ms 0.009 ms 74667 items_per_second=108.607k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_ShallowCopy/100/5 0.068 ms 0.068 ms 11200 items_per_second=14.6286k/s
DomPatchBenchmark/AzDomPatch_Generate_ArrayPrepend_ShallowCopy/100/500 0.082 ms 0.082 ms 8960 items_per_second=12.2009k/s
```
- Patch application
```
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_ShallowCopy/10/5 0.001 ms 0.001 ms 560000 items_per_second=874.146k/s
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_ShallowCopy/10/500 0.001 ms 0.001 ms 560000 items_per_second=874.146k/s
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_ShallowCopy/100/5 0.004 ms 0.004 ms 172308 items_per_second=250.63k/s
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_ShallowCopy/100/500 0.004 ms 0.004 ms 179200 items_per_second=260.655k/s
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_DeepCopy/10/5 0.005 ms 0.005 ms 112000 items_per_second=193.73k/s
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_DeepCopy/10/500 0.005 ms 0.005 ms 112000 items_per_second=193.73k/s
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_DeepCopy/100/5 0.052 ms 0.052 ms 10000 items_per_second=19.3939k/s
DomPatchBenchmark/AzDomPatch_Apply_SimpleReplace_DeepCopy/100/500 0.052 ms 0.052 ms 11200 items_per_second=19.373k/s
DomPatchBenchmark/AzDomPatch_Apply_TopLevelReplace/10/5 0.001 ms 0.001 ms 640000 items_per_second=910.222k/s
DomPatchBenchmark/AzDomPatch_Apply_TopLevelReplace/10/500 0.001 ms 0.001 ms 640000 items_per_second=910.222k/s
DomPatchBenchmark/AzDomPatch_Apply_TopLevelReplace/100/5 0.001 ms 0.001 ms 640000 items_per_second=910.222k/s
DomPatchBenchmark/AzDomPatch_Apply_TopLevelReplace/100/500 0.001 ms 0.001 ms 640000 items_per_second=910.222k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_ShallowCopy/10/5 0.001 ms 0.001 ms 560000 items_per_second=896k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_ShallowCopy/10/500 0.001 ms 0.001 ms 640000 items_per_second=871.489k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_ShallowCopy/100/5 0.004 ms 0.004 ms 160000 items_per_second=232.727k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_ShallowCopy/100/500 0.004 ms 0.004 ms 165926 items_per_second=235.984k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_DeepCopy/10/5 0.005 ms 0.005 ms 112000 items_per_second=193.73k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_DeepCopy/10/500 0.005 ms 0.005 ms 112000 items_per_second=193.73k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_DeepCopy/100/5 0.053 ms 0.053 ms 10000 items_per_second=18.8235k/s
DomPatchBenchmark/AzDomPatch_Apply_KeyRemove_DeepCopy/100/500 0.051 ms 0.052 ms 10000 items_per_second=19.3939k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_ShallowCopy/10/5 0.001 ms 0.001 ms 497778 items_per_second=692.561k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_ShallowCopy/10/500 0.001 ms 0.001 ms 497778 items_per_second=692.561k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_ShallowCopy/100/5 0.006 ms 0.006 ms 112000 items_per_second=174.829k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_ShallowCopy/100/500 0.006 ms 0.006 ms 100000 items_per_second=177.778k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_DeepCopy/10/5 0.005 ms 0.005 ms 112000 items_per_second=193.73k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_DeepCopy/10/500 0.005 ms 0.005 ms 100000 items_per_second=188.235k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_DeepCopy/100/5 0.053 ms 0.052 ms 11200 items_per_second=19.373k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayAppend_DeepCopy/100/500 0.052 ms 0.053 ms 11200 items_per_second=18.8632k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_ShallowCopy/10/5 0.001 ms 0.001 ms 560000 items_per_second=874.146k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_ShallowCopy/10/500 0.001 ms 0.001 ms 560000 items_per_second=874.146k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_ShallowCopy/100/5 0.004 ms 0.004 ms 179200 items_per_second=260.655k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_ShallowCopy/100/500 0.004 ms 0.004 ms 179200 items_per_second=260.655k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_DeepCopy/10/5 0.005 ms 0.005 ms 100000 items_per_second=193.939k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_DeepCopy/10/500 0.005 ms 0.005 ms 100000 items_per_second=193.939k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_DeepCopy/100/5 0.052 ms 0.052 ms 11200 items_per_second=19.373k/s
DomPatchBenchmark/AzDomPatch_Apply_ArrayPrepend_DeepCopy/100/500 0.053 ms 0.053 ms 10000 items_per_second=18.8235k/s
```
At a glance, patch generation using `GenerateHierarchicalDeltaPatch` is slower than applying its created patches, but not prohibitively so. Ideally patches shouldn't be recreated unnecessarily, but especially when diffing `Value`s that have been copied and then mutated, a generate + apply operation similar to what prefabs currently do is reasonably fast.
Signed-off-by: Nicholas Van Sickle <nvsickle@amazon.com>
Nicholas Van Sickle
e06b8782cc