opendev/gerrit
Code Issues Proposed changes

Lazy load HighlightJS library

Browse Source 
Previously, the HighlightJS library (HLJS) was being Vulcanized into the
PolyGerrit build, even if the library was not being used (for example if
the user does not navigate to a diff or has syntax highlighting disabled
in preferences). Because HLJS is a substantial file -- ranging in size
from 47KB to more than 455KB (ungizpped) depending on the build
environment, this is not ideal.

In order to lazy load a JS library:

1)  It needs to be copied into the built WAR file to be addressable, and
2)  It should not be Vulcanized into the built gr-app.js file.

Previously, the PolyGerrit build system supported copying and
non-vulcanizing exactly one JS library: namely webcomponents-lite.js.
This change generalizes the mechanism by which webcomponents is copied
and adds HLJS to that list. This satisfies **1**.

Furthermore, the GR-SYNTAX-LAYER is rewritten to dynamically import HLJS
in the `process` step by crafting a SCRIPT element and attaching it to
the local DOM. (Syntax processing is invoked only after entire diff is
rendered.) Code that depends on the library awaits this load before
using it. Thus, the conventional JS import can be removed from the
element's HTML and will not be recognized by the Vulcanize phase. This
satisfies **2**.

Tests are updated accordingly.

Bug: Issue 4298
Change-Id: I9a95d6d4c211cd8f1ca1bc4daec770b64b22b3d1
This commit is contained in:
Wyatt Allen 2016-08-01 15:23:50 -07:00
parent f1063a2690
commit db56a6f62c
4 changed files with 127 additions and 88 deletions
polygerrit-ui/app
BUCK
elements/diff/gr-syntax-layer
gr-syntax-layer.htmlgr-syntax-layer.jsgr-syntax-layer_test.html

21
polygerrit-ui/app/BUCK

@ -14,7 +14,21 @@ APP_SRCS = glob(
'test/**',
] + WCT_TEST_PATTERNS + PY_TEST_PATTERNS)
WEBJS = 'bower_components/webcomponentsjs/webcomponents-lite.js'
# List libraries to be copied statically into the build. (i.e. Libraries not
# expected to be Vulcanized.)
WEB_JS_LIBS = [
('bower_components/webcomponentsjs', 'webcomponents-lite.js'),
('bower_components/highlightjs', 'highlight.min.js'),
]
# Map the static libraries to commands for the polygerrit_ui rule.
JS_LIBS_MKDIR_CMDS = []
JS_LIBS_UNZIP_CMDS = []
for lib in WEB_JS_LIBS:
JS_LIBS_MKDIR_CMDS.append('mkdir -p ' + lib[0])
path = lib[0] + '/' + lib[1]
cmd = 'unzip -p $(location //polygerrit-ui:polygerrit_components) %s>%s' % (path, path)
JS_LIBS_UNZIP_CMDS.append(cmd)
# TODO(dborowitz): Putting these rules in this package avoids having to handle
# the app/ prefix like we would have to if this were in the parent directory.
@ -26,11 +40,12 @@ genrule(
cmd = ' && '.join([
'mkdir $TMP/polygerrit_ui',
'cd $TMP/polygerrit_ui',
'mkdir -p {fonts,elements,bower_components/webcomponentsjs}',
'mkdir -p {fonts,elements}',
' && '.join(JS_LIBS_MKDIR_CMDS),
'unzip -qd fonts $(location //polygerrit-ui:fonts)',
'unzip -qd elements $(location :gr-app)',
'cp -rp $SRCDIR/* .',
'unzip -p $(location //polygerrit-ui:polygerrit_components) %s>%s' % (WEBJS, WEBJS),
' && '.join(JS_LIBS_UNZIP_CMDS),
'cd $TMP',
'zip -9qr $OUT .',
]),

1
polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.html

@ -14,7 +14,6 @@ See the License for the specific language governing permissions and
limitations under the License.
-->
<link rel="import" href="../../../bower_components/polymer/polymer.html">
<script src="../../../bower_components/highlightjs/highlight.min.js"></script>
<dom-module id="gr-syntax-layer">
<script src="../gr-diff/gr-diff-line.js"></script>
<script src="../gr-diff-highlight/gr-annotation.js"></script>

77
polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.js

@ -31,8 +31,8 @@
'text/x-sql': 'sql',
'text/x-scala': 'scala',
};
var ASYNC_DELAY = 10;
var HLJS_PATH = '../../../bower_components/highlightjs/highlight.min.js';
Polymer({
is: 'gr-syntax-layer',
@ -63,10 +63,6 @@
_processHandle: Number,
},
attached: function() {
hljs.configure({classPrefix: 'gr-diff gr-syntax gr-syntax-'});
},
addListener: function(fn) {
this.push('_listeners', fn);
},
@ -139,36 +135,38 @@
lastNotify: {left: 1, right: 1},
};
return new Promise(function(resolve) {
var nextStep = function() {
this._processHandle = null;
this._processNextLine(state);
return this._loadHLJS().then(function() {
return new Promise(function(resolve) {
var nextStep = function() {
this._processHandle = null;
this._processNextLine(state);
// Move to the next line in the section.
state.lineIndex++;
// Move to the next line in the section.
state.lineIndex++;
// If the section has been exhausted, move to the next one.
if (this._isSectionDone(state)) {
state.lineIndex = 0;
state.sectionIndex++;
}
// If the section has been exhausted, move to the next one.
if (this._isSectionDone(state)) {
state.lineIndex = 0;
state.sectionIndex++;
}
// If all sections have been exhausted, finish.
if (state.sectionIndex >= this.diff.content.length) {
resolve();
this._notify(state);
return;
}
// If all sections have been exhausted, finish.
if (state.sectionIndex >= this.diff.content.length) {
resolve();
this._notify(state);
return;
}
if (state.sectionIndex !== 0 && state.lineIndex % 100 === 0) {
this._notify(state);
this._processHandle = this.async(nextStep, ASYNC_DELAY);
} else {
nextStep.call(this);
}
};
if (state.sectionIndex !== 0 && state.lineIndex % 100 === 0) {
this._notify(state);
this._processHandle = this.async(nextStep, ASYNC_DELAY);
} else {
nextStep.call(this);
}
};
this._processHandle = this.async(nextStep, 1);
this._processHandle = this.async(nextStep, 1);
}.bind(this));
}.bind(this));
},
@ -309,5 +307,24 @@
fn(start, end, side);
});
},
/**
* Load and configure the HighlightJS library. If the library is already
* loaded, then do nothing and resolve.
* @return {Promise}
*/
_loadHLJS: function() {
if (window.hljs) { return Promise.resolve(); }
return new Promise(function(resolve) {
var script = document.createElement('script');
script.src = HLJS_PATH;
script.onload = function() {
hljs.configure({classPrefix: 'gr-diff gr-syntax gr-syntax-'});
resolve();
};
Polymer.dom(this.root).appendChild(script);
}.bind(this));
}
});
})();

116
polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer_test.html

@ -131,6 +131,7 @@ limitations under the License.
test('process while disabled does nothing', function(done) {
var processNextSpy = sandbox.spy(element, '_processNextLine');
element.enabled = false;
var loadHLJSSpy = sandbox.spy(element, '_loadHLJS');
var processPromise = element.process();
@ -138,76 +139,83 @@ limitations under the License.
assert.isFalse(processNextSpy.called);
assert.equal(element._baseRanges.length, 0);
assert.equal(element._revisionRanges.length, 0);
assert.isFalse(loadHLJSSpy.called);
done();
});
});
test('process highlight ipsum', function(done) {
element.diff.meta_a.content_type = 'application/json';
element.diff.meta_b.content_type = 'application/json';
var processNextSpy = sandbox.spy(element, '_processNextLine');
var highlightStub = sandbox.stub(hljs, 'highlight', function(
lang, line, ignore, state) {
return {
value: line.replace(/ipsum/, '<span class="foobar">ipsum</span>'),
top: state === undefined ? 1 : state + 1,
};
suite('after hljs load', function() {
setup(function(done) {
element._loadHLJS().then(done);
});
var processPromise = element.process();
test('process highlight ipsum', function(done) {
element.diff.meta_a.content_type = 'application/json';
element.diff.meta_b.content_type = 'application/json';
var processNextSpy = sandbox.spy(element, '_processNextLine');
var highlightStub = sandbox.stub(hljs, 'highlight', function(
lang, line, ignore, state) {
return {
value: line.replace(/ipsum/, '<span class="foobar">ipsum</span>'),
top: state === undefined ? 1 : state + 1,
};
});
processPromise.then(function() {
var linesA = diff.meta_a.lines;
var linesB = diff.meta_b.lines;
var processPromise = element.process();
assert.isTrue(processNextSpy.called);
assert.equal(element._baseRanges.length, linesA);
assert.equal(element._revisionRanges.length, linesB);
processPromise.then(function() {
var linesA = diff.meta_a.lines;
var linesB = diff.meta_b.lines;
assert.equal(highlightStub.callCount, linesA + linesB);
assert.isTrue(processNextSpy.called);
assert.equal(element._baseRanges.length, linesA);
assert.equal(element._revisionRanges.length, linesB);
// The first line of both sides have a range.
[element._baseRanges[0], element._revisionRanges[0]]
.forEach(function(range) {
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 'lorem '.length);
assert.equal(range[0].length, 'ipsum'.length);
});
assert.equal(highlightStub.callCount, linesA + linesB);
// There are no ranges from ll.1-12 on the left and ll.1-11 on the
// right.
element._baseRanges.slice(1, 12)
.concat(element._revisionRanges.slice(1, 11))
.forEach(function(range) {
assert.equal(range.length, 0);
});
// The first line of both sides have a range.
[element._baseRanges[0], element._revisionRanges[0]]
.forEach(function(range) {
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 'lorem '.length);
assert.equal(range[0].length, 'ipsum'.length);
});
// There should be another pair of ranges on l.13 for the left and l.12
// for the right.
[element._baseRanges[13], element._revisionRanges[12]]
.forEach(function(range) {
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 32);
assert.equal(range[0].length, 'ipsum'.length);
});
// There are no ranges from ll.1-12 on the left and ll.1-11 on the
// right.
element._baseRanges.slice(1, 12)
.concat(element._revisionRanges.slice(1, 11))
.forEach(function(range) {
assert.equal(range.length, 0);
});
// The next group should have a similar instance on either side.
// There should be another pair of ranges on l.13 for the left and
// l.12 for the right.
[element._baseRanges[13], element._revisionRanges[12]]
.forEach(function(range) {
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 32);
assert.equal(range[0].length, 'ipsum'.length);
});
var range = element._baseRanges[15];
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 34);
assert.equal(range[0].length, 'ipsum'.length);
// The next group should have a similar instance on either side.
range = element._revisionRanges[14];
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 35);
assert.equal(range[0].length, 'ipsum'.length);
var range = element._baseRanges[15];
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 34);
assert.equal(range[0].length, 'ipsum'.length);
done();
range = element._revisionRanges[14];
assert.equal(range.length, 1);
assert.equal(range[0].className, 'foobar');
assert.equal(range[0].start, 35);
assert.equal(range[0].length, 'ipsum'.length);
done();
});
});
});