RFR: 7903616: Bad formatting of layout string for structs with nested anon structs/unions

[Maurizio Cimadamore]

This PR fixes an indentation issue when generating a struct layout string.

Example:


struct Foo {
    struct {
        int x;
        union {
            int y;
            int z;
        };
    };
}; 


For this, jextract generates:


    private static final GroupLayout $LAYOUT = MemoryLayout.structLayout(
        MemoryLayout.structLayout(
        foo_h.C_INT.withName("x"),
        MemoryLayout.unionLayout(
        foo_h.C_INT.withName("y"),
        foo_h.C_INT.withName("z")
    ).withName("$anon$7:9")
    ).withName("$anon$5:5")
    ).withName("Foo");


With the fix in this PR, the generated string is:


    private static final GroupLayout $LAYOUT = MemoryLayout.structLayout(
        MemoryLayout.structLayout(
            foo_h.C_INT.withName("x"),
            MemoryLayout.unionLayout(
                foo_h.C_INT.withName("y"),
                foo_h.C_INT.withName("z")
            ).withName("$anon$7:9")
        ).withName("$anon$5:5")
    ).withName("Foo");


The fix is to correctly track required indentation when descending into a scoped declaration.

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

Commit messages:
 - Initial push

Changes: https://git.openjdk.org/jextract/pull/170/files
 Webrev: https://webrevs.openjdk.org/?repo=jextract&pr=170&range=00
  Issue: https://bugs.openjdk.org/browse/CODETOOLS-7903616
  Stats: 9 lines in 1 file changed: 1 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jextract/pull/170.diff
  Fetch: git fetch https://git.openjdk.org/jextract.git pull/170/head:pull/170

PR: https://git.openjdk.org/jextract/pull/170