Module: RSpecTracer::Tracker::FileDigest Private

Defined in:
lib/rspec_tracer/tracker/file_digest.rb

Overview

This module is part of a private API. You should avoid using this module if possible, as it may be removed or be changed in the future.

Process-wide SHA256 file-digest cache. Keyed on absolute path with [mtime_ns, size] as the freshness check — when the file’s stat timestamps + size match the cached values, the prior digest is reused; otherwise the digest is recomputed and the cache entry refreshed.

The cache is populated lazily and never evicted within a process. Tracer runs are bounded (one rspec invocation per process), so unbounded growth is bounded by the project’s dependency-graph size (typically << 10k unique files).

SystemCallError on stat / digest is treated as “file gone / unreadable” and returns nil — same graceful-degradation contract every call site already implemented locally before this module centralized them.

Thread-safety: rspec example execution is single-threaded (cold-subprocess contract); the cache uses a plain Hash without locking. Multi-threaded callers are unsupported (consistent with the rest of the tracer’s threading model).

Class Method Summary collapse

Class Method Details

.compute(path) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns the SHA256 hex digest of ‘path`, or nil when the file can’t be stat’d (missing / permission denied / racey delete). Subsequent calls for the same path with unchanged stat skip the digest computation entirely.



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# File 'lib/rspec_tracer/tracker/file_digest.rb', line 35

def compute(path)
  stat = File.stat(path)
  key = (stat.mtime.to_i * 1_000_000_000) + stat.mtime.nsec
  size = stat.size
  cache = (@cache ||= {})
  cached = cache[path]
  return cached[2] if cached && cached[0] == key && cached[1] == size

  digest = Digest::SHA256.file(path).hexdigest
  cache[path] = [key, size, digest]
  digest
rescue SystemCallError
  nil
end

.reset! ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Drop the cache. Tests that mutate file content in-place at nanosecond granularity (and so might collide on the mtime+size key) should call this between scenarios. Normal tracer runs never need it — the cache lives for one rspec invocation only.



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# File 'lib/rspec_tracer/tracker/file_digest.rb', line 55

def reset!
  @cache = {}
end