This allows both boolean and string-type preferences. It
also implements a system where prefs that are read from a
configuration file can be reset back to their initial value,
which is useful in a number of cases e.g. when running tests
to ensure that each test starts with the same values for
the prefs.
Fix#7609, "error: unable to create file tests/ref/hello_a?foo#bar.html
(Invalid argument)" during git checkout on Windows.
Behavior change: passing an nonexistent file name on the command line
now shows a blank page (like network errors)
rather than exit with an error message.
Fail on unrecognized debug option
Refs: https://github.com/servo/servo/issues/7142
Ran some basic functional tests:
```
$ ./mach run -d -Z bubble-widths,disable-canvas-aa,trace-layout tests/ref/blur_ref.html
$ ./mach run -d -Z help
Usage: /Users/greg/servo/target/debug/servo debug option,[options,...]
where options include
Options:
bubble-widths Bubble intrinsic widths separately like other engines.
disable-text-aa Disable antialiasing of rendered text.
disable-canvas-aa Disable antialiasing on the HTML canvas element.
dump-flow-tree Print the flow tree after each layout.
dump-display-list Print the display list after each layout.
dump-display-list-json Print the display list in JSON form.
dump-display-list-optimized Print optimized display list (at paint time).
relayout-event Print notifications when there is a relayout.
profile-tasks Instrument each task, writing the output to a file.
show-compositor-borders Paint borders along layer and tile boundaries.
show-fragment-borders Paint borders along fragment boundaries.
show-parallel-paint Overlay tiles with colors showing which thread painted them.
show-parallel-layout Mark which thread laid each flow out with colors.
paint-flashing Overlay repainted areas with a random color.
trace-layout Write layout trace to an external file for debugging.
validate-display-list-geometry Display an error when display list geometry escapes overflow region.
disable-share-style-cache Disable the style sharing cache.
parallel-display-list-building Build display lists in parallel.
replace-surrogates Replace unpaires surrogates in DOM strings with U+FFFD. See https://github.com/servo/servo/issues/6564
gc-profile Log GC passes and their durations.
$ ./mach run -d -Z blah
error: unrecognized debug option: blah
Servo exited with return value 1
```
Didn't check that setting debug flags actually did anything.
Haven't written much Rust so this feels more verbose than necessary.
Added `disable-canvas-aa` to debug options help.
Should DebugOptions struct derive Clone like Opts does?
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script: Make the resource task communication use IPC channels.
This change makes Servo use serialized messages over IPC channels for resource loading. The goal is to make it easier to make Servo multiprocess in the future. This patch does not make Servo multiprocess now; there are many other channels that need to be changed to IPC before that can happen. It does introduce a dependency on https://github.com/serde-rs/serde and https://github.com/pcwalton/ipc-channel for the first time.
At the moment, `ipc-channel` uses JSON for serialization. This is because serde does not yet have official support for bincode. When serde gains support for bincode, I'll switch to that. For now, however, the JSON encoding and decoding will constitute a significant performance regression in resource loading.
To avoid having to send boxed `AsyncResponseTarget` trait objects across process boundaries, this series of commits changes `AsyncResponseTarget` to wrap a sender only. It is then the client's responsibility to spawn a thread to proxy calls from that sender to the consumer of the resource data. This only had to be done in a few places. In the future, we may want to collapse those threads into one per process to reduce overhead. (It is impossible to continue to use `AsyncResponseTarget` as a boxed trait object across processes, regardless of how much work is done on `ipc-channel`. Vtables are fundamentally incompatible with IPC across mutually untrusting processes.)
In general, I was pretty pleased with how this turned out. The main changes are adding serialization functionality to various objects that `serde` does not know how to serialize natively—the most complicated being Hyper objects—and reworking `AsyncResponseTarget`. The overall structure of the code is unchanged, and other than `AsyncResponseTarget` no functionality was lost in moving to serialization and IPC.
r? @jdm
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