[foreign-memaccess+abi] RFR: 8291639: Improve the ability to visualize a MemorySegment in human readable forms [v13]

Per Minborg duke at openjdk.org
Thu Aug 25 13:57:03 UTC 2022


> This PR improves the ability to visualize a `MemorySegment` in human-readable forms (`ByteBuffer`, `byte[]` or any other memory abstraction can be viewed by means of wrapping).
> 
> It exposes a new method via the new utility class `MemoryInspection`
> 
> 
>     /**
>      * Returns a human-readable view of the provided {@code memory} abstraction by optionally
>      * (if not a {@link MemorySession} and {@link Adapter#ofMemorySegment()} already) copying the contents
>      * to a fresh MemorySegment and then view the resulting MemorySegment through the provided {@code layout}.
>      * <p>
>      * Lines are separated with the system-dependent line separator {@link System#lineSeparator() }.
>      * Otherwise, the exact format of the returned view is unspecified and should not
>      * be acted upon programmatically.
>      * <p>
>      * As an example, a MemorySegment viewed though the following memory layout
>      * {@snippet lang = java:
>      * var layout = MemoryLayout.structLayout(
>      *         ValueLayout.JAVA_INT.withName("x"),
>      *         ValueLayout.JAVA_INT.withName("y")
>      * ).withName("Point");
>      *}
>      * might be rendered to something like this:
>      * {@snippet lang = text:
>      * Point {
>      *   x=1,
>      *   y=2
>      * }
>      *}
>      * <p>
>      * This method is intended to view memory abstractions through small and medium-sized memory layouts.
>      *
>      * @param memory   to be viewed
>      * @param adapter  to apply to the provided memory to determine the size and content of the memory abstraction.
>      * @param layout   to use as a layout when viewing the memory segment
>      * @param renderer to apply when rendering value layouts
>      * @param <M>      the memory abstraction type.
>      * @return a view of the memory abstraction viewed through the memory layout
>      * @throws OutOfMemoryError if the view exceeds the array size VM limit
>      */
>     public static <M> String toString(M memory,
>                                       Adapter<M> adapter,
>                                       MemoryLayout layout,
>                                       ValueLayoutRenderer renderer) {
>                                       
> 
> 
> the existing `HexFormat` class will also get two overloads for MemorySegments.

Per Minborg has updated the pull request incrementally with one additional commit since the last revision:

  Rollback unintended reformatting

-------------

Changes:
  - all: https://git.openjdk.org/panama-foreign/pull/695/files
  - new: https://git.openjdk.org/panama-foreign/pull/695/files/01a44361..8417b4ed

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=panama-foreign&pr=695&range=12
 - incr: https://webrevs.openjdk.org/?repo=panama-foreign&pr=695&range=11-12

  Stats: 5 lines in 1 file changed: 2 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/panama-foreign/pull/695.diff
  Fetch: git fetch https://git.openjdk.org/panama-foreign pull/695/head:pull/695

PR: https://git.openjdk.org/panama-foreign/pull/695


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