This moves part of pref_savePrefs() into PrefHashEntry.
This requires moving StrEscape() higher up to avoid a forward declaration.
Note that clang-format insists on indenting an unrelated comment, I don't know
why.
MozReview-Commit-ID: 7gww3r7t9y4
And invert its sense, renaming as Equals(), because that is easier to think
about.
The patch also reorders some conditions so that
HasDefaultValue()/HasUserValue() is tested before Equals(). This isn't strictly
necessary, but it reads better.
MozReview-Commit-ID: JeGrevDwqKz
This patch:
- partially inlines GetPrefValueFromEntry() at its two call sites, to avoid
repeating the kind check;
- renames it as AssignPrefValueToDomPrefValue().
MozReview-Commit-ID: BUBk3ML6h5O
PrefTypeFlags is a class with a lot of smarts (i.e. methods). PrefHashEntry is
a class with little smarts. This is silly, because PrefTypeFlags is essentially
an internal implementation detail of PrefHashEntry.
This patch merges PrefTypeFlags into PrefHashEntry, so that PrefHashEntry has
all the smarts. This means lots of `pref->mPrefFlags.Foo()` calls become
`pref->Foo()`.
The patch also changes the representation of the type and flags within
PrefHashEntry to use bitfields, which avoids the need for a Flags type and is
much simpler than the old approach.
MozReview-Commit-ID: 4Yt9OtBzh9e
It's the user value that's sticky, not the default value. Though we typically
talk about the entire pref being sticky, so that's what this patch does.
MozReview-Commit-ID: 8THuRCTZ7uw
Because it holds 8-bit strings, which only need 1 byte alignment.
For the profile on my Linux box, in every process this reduces the size of the
arena by 1 chunk, from 120 KiB to 112 KiB.
MozReview-Commit-ID: 8ozrLIq5ZZ4
This patch renames it as gInstallingCallback, adds a comment, and reduces the
scope of the AUTO_INSTALLING_CALLBACK() objects to the minimum.
MozReview-Commit-ID: EGfnBPVFtmw
This splits the measurements into several buckets, like so:
> 718,528 B (00.40%) -- preferences
> ├──262,176 B (00.14%) ── hash-table
> ├──181,952 B (00.10%) ── callbacks
> ├──122,880 B (00.07%) ── pref-name-arena
> ├───91,872 B (00.05%) ── root-branches
> ├───38,296 B (00.02%) ── string-values
> ├───21,272 B (00.01%) ── cache-data
> └───────80 B (00.00%) ── misc
The patch also measures some things that were previously overlooked.
- String pref values. (The old code had a comment that incorrectly claimed they
were allocated out of an arena.)
- The PrefCallback objects pointed to by entries in nsPrefBranch::mObservers.
And it makes the code more like typical reporters.
- It removes the "AndOtherStuff" from Preferences' measuring method, and
measuring those global structures in
PreferenceServiceReporter::CollectReports().
- It adds `const` where appropriate.
MozReview-Commit-ID: dyNg7ldQdh
This patch also adds some Set*InAnyProcess() methods, and makes nsPrefBranch a
friend of Preferences so it can call those methods.
And it moves the thin Set*() wrapper functions to Preferences.h, alongside
SetUint().
MozReview-Commit-ID: 88HhmcTFZNc
This will allow other functions to be moved into Preferences and be marked as
`private` in subsequent patches.
The patch also renames SetPrefValue() as SetValueFromDom(), because that's a
clearer name.
MozReview-Commit-ID: CB1xmPSmac6
This is unused for now, but will be necessary for nsPrefBranch::Set*() to call
into Preferences::Set*().
The patch also renames some arguments from aPref to aPrefName, because that's a
better name.
MozReview-Commit-ID: 2OPB7CHOgpw
This is nicer than a bool for tracking the Default vs. User distinction, and it
replaces the Preferences.cpp-only WhichValue type.
MozReview-Commit-ID: 8CrdDN2vBJQ
libpref only allows pref modifications in the parent process. This patch
tightens up the checking, which is a bit inconsistent.
- It removes ENSURE_MAIN_PROCESS_WITH_WARNING, which does NS_WARNING on
failure, and replaces its uses with ENSURE_MAIN_PROCESS, which does NS_ERROR
on failure. This required adding an XRE_IsParentProcess() check to one place
in editor/.
- It converts XRE_IsContentProcess() tests to !XRE_IsParentProcess(), because
we now have multiple kinds of non-parent process.
- It uses ENSURE_MAIN_PROCESS to replace other checking code in a few places.
- It improves a comment in HandleDirty().
MozReview-Commit-ID: D8znQWH7ery
InitStaticMembers() is the hottest function within libpref, because it is
called from all the getters and setters. This patch tweaks it so the common
case is handled with a single comparison, instead of two. This is valid because
sPreferences is nulled at the same time that sShutdown is set.
The patch also tweaks some other conditions to take advantage of this fact.
MozReview-Commit-ID: C74fLWOw7bE
They both have two callsites, but in one of those they appear together, where
much of the code can be replaced with a ClearAndPrepareForLength() call.
MozReview-Commit-ID: 1A771gsHWan
Bug 1345294 introduced nsPrefBranch::{get,set}StringPref(), which allowed the
getting of utf8 strings from prefs, which previously required using
nsISupportsString with {get,set}ComplexValue. That bug also converted most
uses.
This patch finishes the job.
- It removes the nsISupportsString support.
- It converts existing code that relied on the nsISupportsString.
- It removes the lint that was set up to detect such uses of nsISupportsString.
libpref has callbacks. You can register a callback function against a
particular pref (or pref prefix), and it'll be called when any matching pref
changes.
This is implemented in two layers. The lower layer is the list of CallbackNode
objects, pointed to by gFirstCallback.
The upper layer involves gObserverTable, which is a hash table of ValueObserver
objects. It is used for callbacks registered via
Preferences::RegisterCallback() and Preferences::Add*VarCache(), but not for
observers registered with Preferences::Add{Weak,Strong}Observer(). If multiple
callbacks with identical prefnames, callback functions and MatchKinds occur,
they are commoned up into a single ValueObserver, which is then wrapped by a
single CallbackNode. (The callbacks within a single ValueObserver can have
different void* aClosure args; ValueObserver keeps those in an nsTArray.)
Note also that gObserverTable is very inelegant, with duplication of data
between the keys and the values due it being a
nsRefPtrHashtable<ValueObserverHashKey, ValueObserver> and ValueObserver being
a subclass of ValueObserverHashKey(!)
This extra layer might make sense if there were a lot of commoning up
happening, but there's not. Across all process kinds there is an average of
between 1.2 and 1.7 closures per ValueObserver. The vast majority have 1
closure, and there are a handful that have multiple; the highest number I've
seen is 71.
(Note that this two-layer design probably seemed more natural back when libpref
was spread across multiple files.)
This patch removes the ValueObserver layer. The only tricky part is that there
is a notion of a MatchKind -- ExactMatch or PrefixMatch -- which exists in the
ValueObserverLayer but not in the CallbackNode layer. So the patch moves the
MatchKind into the CallbackNode layer, which is straightforward.
On Linux64 this reduces memory usage by about 40 KiB in the parent process and
about 30 KiB in each content processes.
The performance implications are minor.
- The list of CallbackNodes is a bit longer, so when a pref is changed we must
check more nodes. But we avoid possibly doing prefname matching twice.
- Callback registration is much faster, just a simple list prepend, without any
hash table insertion required.
- Callback unregistration is probably not much different. There is a longer
list to traverse, but no hash table removal.
- Pref lookup is by far the hottest libpref operation, and it's unchanged.
For perf to be genuinely affected would require (a) a *lot* more
almost-duplicate callbacks that would have been commoned up, and (b) frequent
changing of the pref those callbacks are observing. This seems highly unlikely.
MozReview-Commit-ID: 6xo4xmytOf3
Bug 1345294 introduced nsPrefBranch::{get,set}StringPref(), which allowed the
getting of utf8 strings from prefs, which previously required using
nsISupportsString with {get,set}ComplexValue. That bug also converted most
uses.
This patch finishes the job.
- It removes the nsISupportsString support.
- It converts existing code that relied on the nsISupportsString.
- It removes the lint that was set up to detect such uses of nsISupportsString.
