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- # graceful-fs
-
- graceful-fs functions as a drop-in replacement for the fs module,
- making various improvements.
-
- The improvements are meant to normalize behavior across different
- platforms and environments, and to make filesystem access more
- resilient to errors.
-
- ## Improvements over [fs module](https://nodejs.org/api/fs.html)
-
- * Queues up `open` and `readdir` calls, and retries them once
- something closes if there is an EMFILE error from too many file
- descriptors.
- * fixes `lchmod` for Node versions prior to 0.6.2.
- * implements `fs.lutimes` if possible. Otherwise it becomes a noop.
- * ignores `EINVAL` and `EPERM` errors in `chown`, `fchown` or
- `lchown` if the user isn't root.
- * makes `lchmod` and `lchown` become noops, if not available.
- * retries reading a file if `read` results in EAGAIN error.
-
- On Windows, it retries renaming a file for up to one second if `EACCESS`
- or `EPERM` error occurs, likely because antivirus software has locked
- the directory.
-
- ## USAGE
-
- ```javascript
- // use just like fs
- var fs = require('graceful-fs')
-
- // now go and do stuff with it...
- fs.readFileSync('some-file-or-whatever')
- ```
-
- ## Global Patching
-
- If you want to patch the global fs module (or any other fs-like
- module) you can do this:
-
- ```javascript
- // Make sure to read the caveat below.
- var realFs = require('fs')
- var gracefulFs = require('graceful-fs')
- gracefulFs.gracefulify(realFs)
- ```
-
- This should only ever be done at the top-level application layer, in
- order to delay on EMFILE errors from any fs-using dependencies. You
- should **not** do this in a library, because it can cause unexpected
- delays in other parts of the program.
-
- ## Changes
-
- This module is fairly stable at this point, and used by a lot of
- things. That being said, because it implements a subtle behavior
- change in a core part of the node API, even modest changes can be
- extremely breaking, and the versioning is thus biased towards
- bumping the major when in doubt.
-
- The main change between major versions has been switching between
- providing a fully-patched `fs` module vs monkey-patching the node core
- builtin, and the approach by which a non-monkey-patched `fs` was
- created.
-
- The goal is to trade `EMFILE` errors for slower fs operations. So, if
- you try to open a zillion files, rather than crashing, `open`
- operations will be queued up and wait for something else to `close`.
-
- There are advantages to each approach. Monkey-patching the fs means
- that no `EMFILE` errors can possibly occur anywhere in your
- application, because everything is using the same core `fs` module,
- which is patched. However, it can also obviously cause undesirable
- side-effects, especially if the module is loaded multiple times.
-
- Implementing a separate-but-identical patched `fs` module is more
- surgical (and doesn't run the risk of patching multiple times), but
- also imposes the challenge of keeping in sync with the core module.
-
- The current approach loads the `fs` module, and then creates a
- lookalike object that has all the same methods, except a few that are
- patched. It is safe to use in all versions of Node from 0.8 through
- 7.0.
-
- ### v4
-
- * Do not monkey-patch the fs module. This module may now be used as a
- drop-in dep, and users can opt into monkey-patching the fs builtin
- if their app requires it.
-
- ### v3
-
- * Monkey-patch fs, because the eval approach no longer works on recent
- node.
- * fixed possible type-error throw if rename fails on windows
- * verify that we *never* get EMFILE errors
- * Ignore ENOSYS from chmod/chown
- * clarify that graceful-fs must be used as a drop-in
-
- ### v2.1.0
-
- * Use eval rather than monkey-patching fs.
- * readdir: Always sort the results
- * win32: requeue a file if error has an OK status
-
- ### v2.0
-
- * A return to monkey patching
- * wrap process.cwd
-
- ### v1.1
-
- * wrap readFile
- * Wrap fs.writeFile.
- * readdir protection
- * Don't clobber the fs builtin
- * Handle fs.read EAGAIN errors by trying again
- * Expose the curOpen counter
- * No-op lchown/lchmod if not implemented
- * fs.rename patch only for win32
- * Patch fs.rename to handle AV software on Windows
- * Close #4 Chown should not fail on einval or eperm if non-root
- * Fix isaacs/fstream#1 Only wrap fs one time
- * Fix #3 Start at 1024 max files, then back off on EMFILE
- * lutimes that doens't blow up on Linux
- * A full on-rewrite using a queue instead of just swallowing the EMFILE error
- * Wrap Read/Write streams as well
-
- ### 1.0
-
- * Update engines for node 0.6
- * Be lstat-graceful on Windows
- * first
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