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use parallel queue for all FS operations
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@a-sully
a-sully committed Apr 4, 2023
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Expand Up @@ -94,54 +94,46 @@ A <dfn export id=file>file entry</dfn> additionally consists of
a <dfn for="file entry">lock</dfn> (a string that may exclusively be "`open`", "`taken-exclusive`" or "`taken-shared`")
and a <dfn for="file entry">shared lock count</dfn> (a number representing the number shared locks that are taken at a given point in time).

A user agent has an associated <dfn>file system lock queue</dfn> which is the
A user agent has an associated <dfn>file system queue</dfn> which is the
result of [=starting a new parallel queue=]. This queue is to be used for all
[=tasks=] involving a [=file entry/lock=].
file sytem operations.

<div algorithm>
To <dfn for="file entry/lock">take</dfn> a [=file entry/lock=] with a |value| of
"`exclusive`" or "`shared`" on a given [=file entry=] |file| and with
algorithm |resultAlgorithm|:

1. [=Enqueue the following steps=] to the [=file system lock queue=]:
1. Let |lock| be the |file|'s [=file entry/lock=].
1. Let |count| be the |file|'s [=file entry/shared lock count=].
1. If |value| is "`exclusive`":
1. If |lock| is "`open`":
1. Set lock to "`taken-exclusive`".
1. [=Queue a storage task=] given |file|'s [=relevant global object=] and
|resultAlgorithm| with a value of "`success`".
1. Return.
1. If |value| is "`shared`":
1. If |lock| is "`open`":
1. Set |lock| to "`taken-shared`".
1. Set |count| to 1.
1. [=Queue a storage task=] given |file|'s [=relevant global object=] and
|resultAlgorithm| with a value of "`success`".
1. Return.
1. Otherwise, if |lock| is "`taken-shared`":
1. Increase |count| by 1.
1. [=Queue a storage task=] given |file|'s [=relevant global object=] and
|resultAlgorithm| with a value of "`success`".
1. Return.
1. [=Queue a storage task=] given |file|'s [=relevant global object=] and
|resultAlgorithm| with a value of "`failure`".
"`exclusive`" or "`shared`" on a given [=file entry=] |file|:

1. Let |lock| be the |file|'s [=file entry/lock=].
1. Let |count| be the |file|'s [=file entry/shared lock count=].
1. If |value| is "`exclusive`":
1. If |lock| is "`open`":
1. Set lock to "`taken-exclusive`".
1. Return a value of "`success`".
1. If |value| is "`shared`":
1. If |lock| is "`open`":
1. Set |lock| to "`taken-shared`".
1. Set |count| to 1.
1. Return a value of "`success`".
1. Otherwise, if |lock| is "`taken-shared`":
1. Increase |count| by 1.
1. Return a value of "`success`".
1. Return a value of "`failure`".

Note: These steps must be run on the [=file system queue=].

</div>

<div algorithm>
To <dfn for="file entry/lock">release</dfn> a [=file entry/lock=] on a given
[=file entry=] |file| and with an optional algorithm |onLockReleasedAlgorithm|:

1. [=Enqueue the following steps=] to the [=file system lock queue=]:
1. Let |lock| be the |file|'s associated [=file entry/lock=].
1. Let |count| be the |file|'s [=file entry/shared lock count=].
1. If |lock| is "`taken-shared`":
1. Decrease |count| by 1.
1. If |count| is 0, set |lock| to "`open`".
1. Otherwise, set |lock| to "`open`".
1. If |onLockReleasedAlgorithm| was given, [=queue a storage task=] given
|file|'s [=relevant global object=] and |onLockReleasedAlgorithm|.
[=file entry=] |file|:

1. Let |lock| be the |file|'s associated [=file entry/lock=].
1. Let |count| be the |file|'s [=file entry/shared lock count=].
1. If |lock| is "`taken-shared`":
1. Decrease |count| by 1.
1. If |count| is 0, set |lock| to "`open`".
1. Otherwise, set |lock| to "`open`".

Note: These steps must be run on the [=file system queue=].

</div>

Expand Down Expand Up @@ -511,27 +503,32 @@ The <dfn method for=FileSystemFileHandle>createWritable(|options|)</dfn> method

1. Let |result| be [=a new promise=].
1. Let |locator| be [=this=]'s [=FileSystemHandle/locator=].
1. Run these steps [=in parallel=]:
1. Let |realm| be [=this=]'s [=relevant Realm=].
1. [=Enqueue the following steps=] to the [=file system queue=]:
1. Let |entry| be the result of [=locating an entry=] given |locator|.
1. Let |access| be the result of running |entry|'s
[=file system entry/request access=] given "`readwrite`".
If that throws an exception, [=reject=] |result| with that exception and abort.
If that throws an exception, [=reject=] |result| with that exception and
abort these steps.
1. If |access| is not "{{PermissionState/granted}}",
[=reject=] |result| with a "{{NotAllowedError}}" {{DOMException}} and abort.
[=reject=] |result| with a "{{NotAllowedError}}" {{DOMException}} and
abort these steps.

1. If |entry| is `null`, [=/reject=] |result| with a
"{{NotFoundError}}" {{DOMException}} and abort.
1. [=Assert=]: |entry| is a [=file entry=].
1. Let |lockResultAlgorithm| be an algorithm which takes a |lockResult| and
runs these steps:
1. If |lockResult| is "`failure`", [=reject=] |result| with a
"{{NoModificationAllowedError}}" {{DOMException}} and abort.
1. Let |stream| be the result of <a>creating a new `FileSystemWritableFileStream`</a>
for |entry| in [=this=]'s [=relevant realm=].
1. If |options|.{{FileSystemCreateWritableOptions/keepExistingData}} is true:
1. Set |stream|.[=[[buffer]]=] to a copy of |entry|'s [=file entry/binary data=].
1. [=/Resolve=] |result| with |stream|.
1. [=file entry/lock/take|Take a lock=] with "`shared`" on |entry| and with
|lockResultAlgorithm|.

1. Let |lockResult| be the result of [=file entry/lock/take|taking a lock=]
with "`shared`" on |entry|.
1. If |lockResult| is "`failure`", [=reject=] |result| with a
"{{NoModificationAllowedError}}" {{DOMException}} and abort these steps.

1. Let |stream| be the result of <a>creating a new `FileSystemWritableFileStream`</a>
for |entry| in |realm|.
1. If |options|'s {{FileSystemCreateWritableOptions/keepExistingData}} is true:
1. Set |stream|'s [=[[buffer]]=] to a copy of |entry|'s [=file entry/binary data=].
1. [=/Resolve=] |result| with |stream|.

1. Return |result|.

</div>
Expand Down Expand Up @@ -563,29 +560,33 @@ The <dfn method for=FileSystemFileHandle>createSyncAccessHandle()</dfn> method s

1. Let |result| be [=a new promise=].
1. Let |locator| be [=this=]'s [=FileSystemHandle/locator=].
1. Run these steps [=in parallel=]:
1. Let |realm| be [=this=]'s [=relevant Realm=].
1. [=Enqueue the following steps=] to the [=file system queue=]:
1. Let |entry| be the result of [=locating an entry=] given |locator|.
1. Let |access| be the result of running |entry|'s
[=file system entry/request access=] given "`readwrite`".
If that throws an exception, [=reject=] |result| with that exception and abort.
1. If |access| is not "{{PermissionState/granted}}",
[=reject=] |result| with a "{{NotAllowedError}}" {{DOMException}} and abort.
If that throws an exception, [=reject=] |result| with that exception and
abort these steps.
1. If |access| is not "{{PermissionState/granted}}", [=reject=] |result| with
a "{{NotAllowedError}}" {{DOMException}} and abort these steps.

1. If |entry| is `null`, [=/reject=] |result| with a
"{{NotFoundError}}" {{DOMException}} and abort.
1. [=Assert=]: |entry| is a [=file entry=].

1. If |entry| does not represent a [=/file system entry=] in an [=origin private file system=],
[=reject=] |result| with an "{{InvalidStateError}}" {{DOMException}} and abort.
1. Let |lockResultAlgorithm| be an algorithm which takes a |lockResult| and
runs these steps:
1. If |lockResult| is "`failure`", [=reject=] |result| with a
"{{NoModificationAllowedError}}" {{DOMException}} and abort.
1. Let |handle| be the result of <a>creating a new `FileSystemSyncAccessHandle`</a>
for |entry| in [=this=]'s [=relevant realm=].
1. [=/Resolve=] |result| with |handle|.
1. [=file entry/lock/take|Take a lock=] with "`exclusive`" on |entry| and with
|lockResultAlgorithm|.
[=reject=] |result| with an "{{InvalidStateError}}" {{DOMException}} and
abort these steps.

1. Let |lockResult| be the result of [=file entry/lock/take|taking a lock=]
with "`exclusive`" on |entry|.
1. If |lockResult| is "`failure`", [=reject=] |result| with a
"{{NoModificationAllowedError}}" {{DOMException}} and abort these steps.

1. Let |handle| be the result of <a>creating a new `FileSystemSyncAccessHandle`</a>
for |entry| in |realm|.
1. [=/Resolve=] |result| with |handle|.

1. Return |result|.

</div>
Expand Down Expand Up @@ -1055,30 +1056,38 @@ To
given a [=file entry=] |file| in a [=/Realm=] |realm|:

1. Let |stream| be a [=new=] {{FileSystemWritableFileStream}} in |realm|.
1. Set |stream|.[=FileSystemWritableFileStream/[[file]]=] to |file|.
1. Set |stream|'s [=FileSystemWritableFileStream/[[file]]=] to |file|.
1. Let |writeAlgorithm| be an algorithm which takes a |chunk| argument
and returns the result of running the [=write a chunk=] algorithm with |stream| and |chunk|.
1. Let |closeAlgorithm| be these steps:
1. Let |closeResult| be [=a new promise=].
1. Run these steps [=in parallel=]:
1. Let |access| be the result of running |file|'s [=file system entry/query access=] given "`readwrite`".
1. [=Enqueue the following steps=] to the [=file system queue=]:
1. Let |access| be the result of running |file|'s
[=file system entry/query access=] given "`readwrite`".
1. If |access| is not "{{PermissionState/granted}}",
[=/reject=] |closeResult| with a "{{NotAllowedError}}" {{DOMException}}
and abort.
and abort these steps.

1. Run [=implementation-defined=] malware scans and safe browsing checks.
If these checks fail, [=/reject=] |closeResult| with an "{{AbortError}}" {{DOMException}} and abort.
1. Set |stream|.[=FileSystemWritableFileStream/[[file]]=]'s [=file entry/binary data=] to |stream|.[=[[buffer]]=].
If that throws an exception, [=/reject=] |closeResult| with that exception and abort.
If these checks fail, [=/reject=] |closeResult| with an
"{{AbortError}}" {{DOMException}} and abort these steps.
1. Set |stream|'s [=FileSystemWritableFileStream/[[file]]=]'s
[=file entry/binary data=] to |stream|'s [=[[buffer]]=].
If that throws an exception, [=/reject=] |closeResult| with that
exception and abort these steps.

Note: It is expected that this atomically updates the contents of the
file on disk being written to.

Note: It is expected that this atomically updates the contents of the file on disk
being written to.
1. [=file entry/lock/release|Release the lock=] on
|stream|'s [=FileSystemWritableFileStream/[[file]]=].
1. [=/Resolve=] |closeResult| with `undefined`.

1. Let |onLockReleasedAlgorithm| be this step: [=/Resolve=] |closeResult| with `undefined`.
1. [=file entry/lock/release|Release the lock=] on |stream|'s
[=FileSystemWritableFileStream/[[file]]=] with |onLockReleasedAlgorithm|.
1. Return |closeResult|.
1. Let |abortAlgorithm| be this step: [=file entry/lock/release|release the lock=] on
|stream|.[=FileSystemWritableFileStream/[[file]]=].
1. Let |abortAlgorithm| be these steps:
1. [=enqueue steps|Enqueue this step=] to the [=file system queue=]:
1. [=file entry/lock/release|release the lock=] on
|stream|'s [=FileSystemWritableFileStream/[[file]]=].
1. Let |highWaterMark| be 1.
1. Let |sizeAlgorithm| be an algorithm that returns `1`.
1. [=WritableStream/Set up=] |stream| with <a for="WritableStream/set up"><var
Expand Down Expand Up @@ -1515,10 +1524,11 @@ The <dfn method for=FileSystemSyncAccessHandle>close()</dfn> method steps are:
1. If [=this=]'s [=[[state]]=] is "`closed`", return.
1. Set [=this=]'s [=[[state]]=] to "`closed`".
1. Set |lockReleased| to false.
1. Let |onLockReleasedAlgorithm| be this step: Set |lockReleased| to true.
1. [=file entry/lock/release|Release the lock=] on
[=this=]'s [=FileSystemSyncAccessHandle/[[file]]=] with |onLockReleasedAlgorithm|.
1. [=Pause=] until |lockReleased| is set to true.
1. Let |file| be [=this=]'s [=FileSystemSyncAccessHandle/[[file]]=].
1. [=Enqueue the following steps=] to the [=file system queue=]:
1. [=file entry/lock/release|Release the lock=] on |file|.
1. Set |lockReleased| to true.
1. [=Pause=] until |lockReleased| is true.

Note: This method does not guarantee that all file modifications will be
immediately reflected in the underlying storage device. Call the
Expand Down

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