Ability to read uid/gid of current process and of FileStat

[DartBot]

This issue was originally filed by @seaneagan

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FileStat.mode presumably (see issue #22036) allows detection of whether which roles (world, group, user) have which permissions (read, write, execute, sticky bit, set uid, set gid) to the file/directory being statted. But unless we can access the uid and gid of the current process and the file stat, there is no way to tell which permissions the current process has by virtue of its uid and gid.

[DartBot]

This comment was originally written by @seaneagan

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Some background on how this could be implemented in windows:

baudehlo/node-fs-ext#27

[lrhn]

Added Library-IO, Area-Library, Triaged labels.

[DartBot]

This comment was originally written by @kaendfinger

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See https://code.google.com/p/dart/issues/detail?id=14467 for my proposal for implementing access to UID. I could also extend this to GID too.