- 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>
* Add Dom::Path class for representing positions in a Dom
This also adds Value support for doing a path-based lookup.
The serialized representation is presently compliant with the JSON-pointer spec but the implementation supports Node types and may be later expanded if we require additional functionality (e.g. XPath style conditional querying).
Signed-off-by: Nicholas Van Sickle <nvsickle@amazon.com>
* A bit of Generic DOM tidying/fixup
- Refactor out a test fixture for all DOM tests / benchmarks
- Optimize `GetType` implementation to not use `AZStd::variant::visit` (benchmark included to A/B the implementations)
- Tag a few more mutating Value functions with "Mutable" to avoid astonishing copy-on-writes
Benchmark results for GetType implementation:
```
DomValueBenchmark/AzDomValueGetType_UsingVariantIndex 18.2 ns 18.0 ns 40727273 items_per_second=443.667M/s
DomValueBenchmark/AzDomValueGetType_UsingVariantVisit 32.2 ns 32.2 ns 21333333 items_per_second=248.242M/s
```
Signed-off-by: Nicholas Van Sickle <nvsickle@amazon.com>
- Use a vector for shared string storage (to avoid the double heap allocation for AZStd::string)
- Use a shared heap allocated any for opaque types (instead of an unsafe ref)
- Add a string comparison key lookup benchmark to measure the impact of Name
Signed-off-by: Nicholas Van Sickle <nvsickle@amazon.com>
- Use ref types
- Support using rapidjson::Value in lieu of rapidjson::Document
- Use the existing JSON comparison util function in tests
Signed-off-by: Nicholas Van Sickle <nvsickle@amazon.com>
This change adds a `DomBackend` interface and a `DomBackendRegistry` for backend discovery (currently not hooked up to anything) alongside a JSON backend implementation.
The JSON backend comes with a small suite of unit and performance tests. The unit tests validate generic DOM conversion to and from serialized JSON and rapidjson::Document objects (the support for which lives in `JsonSerializationUtils.h`).
The performance tests show a throughput decrease compared to directly using the rapidjson serializer when mirroring our current pattern of copying strings from the serialized JSON representation, but with the coming in-memory store we have the opportunity to keep the buffer in memory and deserialize in-situ using rapidjson's API, which is consistently at least 100MiB/s faster on my machine (Ryzen Threadripper 3970X). The first parameter is the nested object complexity (N*N, objects with N keys comprised of arrays with N values) and the second parameter is the base size of the strings within each entry of this object.
```
----------------------------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
----------------------------------------------------------------------------------------------------------------------
DomJsonBenchmark/DomDeserializeToDocumentInPlace/10/5 0.050 ms 0.050 ms 10000 bytes_per_second=355.816M/s
DomJsonBenchmark/DomDeserializeToDocumentInPlace/10/50 0.057 ms 0.057 ms 11200 bytes_per_second=386.064M/s
DomJsonBenchmark/DomDeserializeToDocumentInPlace/100/5 4.77 ms 4.88 ms 112 bytes_per_second=364.046M/s
DomJsonBenchmark/DomDeserializeToDocumentInPlace/100/500 11.6 ms 11.7 ms 64 bytes_per_second=554.518M/s
DomJsonBenchmark/DomDeserializeToDocumentWithCopies/10/5 0.084 ms 0.084 ms 7467 bytes_per_second=212.55M/s
DomJsonBenchmark/DomDeserializeToDocumentWithCopies/10/50 0.099 ms 0.100 ms 6400 bytes_per_second=220.608M/s
DomJsonBenchmark/DomDeserializeToDocumentWithCopies/100/5 8.22 ms 8.16 ms 90 bytes_per_second=217.847M/s
DomJsonBenchmark/DomDeserializeToDocumentWithCopies/100/500 23.2 ms 22.9 ms 30 bytes_per_second=283.56M/s
DomJsonBenchmark/JsonUtilsDeserializeToDocument/10/5 0.070 ms 0.070 ms 11200 bytes_per_second=255.049M/s
DomJsonBenchmark/JsonUtilsDeserializeToDocument/10/50 0.086 ms 0.087 ms 8960 bytes_per_second=253.258M/s
DomJsonBenchmark/JsonUtilsDeserializeToDocument/100/5 6.86 ms 6.84 ms 112 bytes_per_second=260.033M/s
DomJsonBenchmark/JsonUtilsDeserializeToDocument/100/500 22.8 ms 22.9 ms 32 bytes_per_second=283.158M/s
```
For `AZ::DOM::Document`, the current plan is to offer helper methods that can load from a file path or string using a given backend that can take advantage of in-place parsing by internally storing the serialized buffer.
Signed-off-by: Nicholas Van Sickle <nvsickle@amazon.com>
Chris Burel
Nicholas Van Sickle