68 lines
2.2 KiB
Markdown
68 lines
2.2 KiB
Markdown
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# DarkReflection
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DarkReflection brings FULL reflection back to new java versions.
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There are several strategies for different java versions, allowing for
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compatibility across *all* versions of OpenJDK from 8 to 22. (Other JDKs
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are likely but not tested to work.)
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## Strategies
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### Class access
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Class access is how DR gets the fields, methods, and constructors of a class.
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**Basic** uses the getDeclaredX() methods. This does not work in the most
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recent few versions.
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**NativeGet** uses the underlying getDeclaredX0() methods. This is less
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performant, but works on *all stable java versions*. (Early access versions
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are to be tested soon.)
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### Field access
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Field access is how DR reads and writes to/from fields that are private or
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final.
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**Basic** uses the setAccessible(true) call.
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**Adapted** uses the DarkAccessibleObject helper, which uses an unsafe to
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change the `accessible` field of the AccessibleObject. At first, this
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tries to use getDeclaredField to obtain the field handle, then falls back
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to a FakeAccessibleObject, which is a class with the same memory layout as
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AccessibleObject, to get the field offset.
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**Unsafe** completely bypasses the AccessibleObject part by using the unsafe
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on the field directly.
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### FieldByName access
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**GetDeclaredField** uses the regular Field strategy by wrapping the name
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in the basic getDeclaredField().
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**DarkReflection** uses the regular Field strategy, but obtains the field
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handle using the Class strategy instead.
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**Unsafe** is currently unnecessary, and uses a hidden unsafe method to obtain
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the field offset directly from the name. Then, it uses the Unsafe Field
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strategy on that offset.
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## UnsafeCompat
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DarkReflection also exposes a consistent unsafe API, that ports Java 8's
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`defineClass` method to newer versions, and backports & opens the hidden
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objectFieldOffset(name) method.
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As the unsafe API shifts further, more and more will be added to the
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UnsafeCompat API.
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This is accessed through the UnsafeProvider.
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## Does this always work?
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I treat any malfunction or absence of function as a bug, but I cannot
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guarantee reliability as this is simply a hobby project of mine.
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Feel free to test this on as many java versions and runtimes as possible.
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