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Use the regular preprocess-function for the CSS files as well

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An old shortcoming of the `preprocessCSS`-function is its complete lack of support for our "normal" defines, which makes it very difficult to have build-specific CSS rules. Recently we've started using specially crafted comments to remove CSS rules from the MOZCENTRAL build, but (ab)using the `preprocessCSS`-function in this way really doesn't feel great.
However, it turns out to be surprisingly simple to instead use the "regular" `preprocess`-function for the CSS files as well. The only special-handling that's still necessary is the helper-function for dealing with CSS-imports, but apart from that everything seems to just work.

One reason, as far as I can tell, for having a separate `preprocessCSS`-function was likely that we originally used *lots* of vendor-prefixed CSS rules in our CSS files. With improvements over the years, especially thanks to Autoprefixer and PostCSS, we've been able to remove *almost* all non-standard CSS rules and the need for special-casing the CSS parsing has mostly vanished.

*Please note:* As part of testing this patch I've diffed the output of `gulp generic`, `gulp mozcentral`, and `gulp chromium` against the `master`-branch to check that there was no obvious breakage.
This commit is contained in:
Jonas Jenwald 2022-05-07 22:00:54 +02:00
parent f8838eb794
commit d1f13a6af3
5 changed files with 61 additions and 91 deletions
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98
external/builder/builder.js vendored
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@ -38,9 +38,25 @@ function preprocess(inFilename, outFilename, defines) {
return fs.realpathSync(inFilename) + ":" + lineNumber;
}
function expandCssImports(content, baseUrl) {
return content.replace(
/^\s*@import\s+url\(([^)]+)\);\s*$/gm,
function (all, url) {
const file = path.join(path.dirname(baseUrl), url);
const imported = fs.readFileSync(file, "utf8").toString();
return expandCssImports(imported, file);
}
);
}
// TODO make this really read line by line.
const lines = fs.readFileSync(inFilename).toString().split("\n");
const totalLines = lines.length;
let content = fs.readFileSync(inFilename, "utf8").toString();
// Handle CSS-imports first, when necessary.
if (/\.css$/i.test(inFilename)) {
content = expandCssImports(content, inFilename);
}
const lines = content.split("\n"),
totalLines = lines.length;
let out = "";
let i = 0;
function readLine() {
@ -123,7 +139,7 @@ function preprocess(inFilename, outFilename, defines) {
let state = STATE_NONE;
const stack = [];
const control =
/^(?:\/\/|<!--)\s*#(if|elif|else|endif|expand|include|error)\b(?:\s+(.*?)(?:-->)?$)?/;
/^(?:\/\/|\s*\/\*|<!--)\s*#(if|elif|else|endif|expand|include|error)\b(?:\s+(.*?)(?:\*\/|-->)?$)?/;
while ((line = readLine()) !== null) {
++lineNumber;
@ -199,82 +215,6 @@ function preprocess(inFilename, outFilename, defines) {
}
exports.preprocess = preprocess;
function preprocessCSS(inFilename, outFilename, defines) {
function hasPrefixedMozcentral(line) {
return /(^|\W)-(ms|o|webkit)-\w/.test(line);
}
function expandImports(content, baseUrl) {
return content.replace(
/^\s*@import\s+url\(([^)]+)\);\s*$/gm,
function (all, url) {
const file = path.join(path.dirname(baseUrl), url);
const imported = fs.readFileSync(file, "utf8").toString();
return expandImports(imported, file);
}
);
}
function removePrefixed(content, hasPrefixedFilter) {
const lines = content.split(/\r?\n/g);
let i = 0;
while (i < lines.length) {
const line = lines[i];
if (!hasPrefixedFilter(line)) {
i++;
continue;
}
if (/\{\s*$/.test(line)) {
let bracketLevel = 1;
let j = i + 1;
while (j < lines.length && bracketLevel > 0) {
const checkBracket = /([{}])\s*$/.exec(lines[j]);
if (checkBracket) {
if (checkBracket[1] === "{") {
bracketLevel++;
} else if (!lines[j].includes("{")) {
bracketLevel--;
}
}
j++;
}
lines.splice(i, j - i);
} else if (/[};]\s*$/.test(line)) {
lines.splice(i, 1);
} else {
// multiline? skipping until next directive or bracket
do {
lines.splice(i, 1);
} while (
i < lines.length &&
!/\}\s*$/.test(lines[i]) &&
!lines[i].includes(":")
);
if (i < lines.length && /\S\s*}\s*$/.test(lines[i])) {
lines[i] = lines[i].substring(lines[i].indexOf("}"));
}
}
// collapse whitespaces
while (lines[i] === "" && lines[i - 1] === "") {
lines.splice(i, 1);
}
}
return lines.join("\n");
}
if (!defines) {
throw new Error("Missing CSS preprocessor defines.");
}
let content = fs.readFileSync(inFilename, "utf8").toString();
content = expandImports(content, inFilename);
if (defines.MOZCENTRAL) {
content = removePrefixed(content, hasPrefixedMozcentral);
}
fs.writeFileSync(outFilename, content);
}
exports.preprocessCSS = preprocessCSS;
/**
* Merge two defines arrays. Values in the second param will override values in
* the first.