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extension: fix truncate in defineFile; refactor/encap defineFile 

truncate was still assuming fixed path instead of passing whole req
object on to setData/getData.
This commit is contained in:
Omar Rizwan 2021-03-26 02:21:14 -07:00
parent 383096da00
commit 8fbfa9a7c9
1 changed files with 91 additions and 85 deletions
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176
extension/background.js
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@ -61,89 +61,93 @@ const utf8ArrayToString = (function() {
return utf8 => decoder.decode(utf8);
})();
const Cache = {
// used when you open a file to cache the content we got from the
// browser until you close that file. (so we can respond to
// individual chunk read() and write() requests without doing a
// whole new conversation with the browser and regenerating the
// content -- important for taking a screenshot, for instance)
store: {}, nextHandle: 0,
storeObject(object) {
const handle = ++this.nextHandle;
this.store[handle] = object;
return handle;
},
getObjectForHandle(handle) { return this.store[handle]; },
setObjectForHandle(handle, object) { this.store[handle] = object; },
removeObjectForHandle(handle) { delete this.store[handle]; }
};
function toUtf8Array(stringOrArray) {
if (typeof stringOrArray == 'string') { return stringToUtf8Array(stringOrArray); }
else { return stringOrArray; }
}
const defineFile = (getData, setData) => ({
// Generates a full set of file operations (so clients can read and
// write sections of the file, stat it to get its size and see it
// show up in ls, etc), given getData and setData functions that
// define the contents of the entire file.
// Helper function: generates a full set of file operations that you
// can use as a route handler (so clients can read and write
// sections of the file, stat it to get its size and see it show up
// in ls, etc), given getData and setData functions that define the
// contents of the entire file.
const defineFile = (function() {
const Cache = {
// used when you open a file to cache the content we got from the
// browser until you close that file. (so we can respond to
// individual chunk read() and write() requests without doing a
// whole new conversation with the browser and regenerating the
// content -- important for taking a screenshot, for instance)
store: {}, nextHandle: 0,
storeObject(object) {
const handle = ++this.nextHandle;
this.store[handle] = object;
return handle;
},
getObjectForHandle(handle) { return this.store[handle]; },
setObjectForHandle(handle, object) { this.store[handle] = object; },
removeObjectForHandle(handle) { delete this.store[handle]; }
};
// getData: (req: Request U Vars) -> Promise<contentsOfFile: String|Uint8Array>
// setData [optional]: (req: Request U Vars, newContentsOfFile: String) -> Promise<>
// You can override file operations (like `truncate` or `getattr`)
// in the returned set if you want different behavior from what's
// defined here.
async getattr(req) {
return {
st_mode: unix.S_IFREG | 0444 | (setData ? 0222 : 0),
st_nlink: 1,
// you'll want to override this if getData() is slow, because
// getattr() gets called a lot more cavalierly than open().
st_size: toUtf8Array(await getData(req)).length
};
},
// We call getData() once when the file is opened, then cache that
// data for all subsequent reads from that application.
async open(req) {
const data = !(req.flags & unix.O_TRUNC) ? await getData(req) : "";
return { fh: Cache.storeObject(toUtf8Array(data)) };
},
async read({fh, size, offset}) {
return { buf: String.fromCharCode(...Cache.getObjectForHandle(fh).slice(offset, offset + size)) }
},
async write(req) {
const {fh, offset, buf} = req;
let arr = Cache.getObjectForHandle(fh);
const bufarr = stringToUtf8Array(buf);
if (offset + bufarr.length > arr.length) {
const newArr = new Uint8Array(offset + bufarr.length);
newArr.set(arr.slice(0, Math.min(offset, arr.length)));
arr = newArr;
Cache.setObjectForHandle(fh, arr);
}
arr.set(bufarr, offset);
// I guess caller should override write() if they want to actually
// patch and not just re-set the whole string (for example,
// if they want to hot-reload just one function the user modified)
await setData(req, utf8ArrayToString(arr)); return { size: bufarr.length };
},
async release({fh}) { Cache.removeObjectForHandle(fh); return {}; },
async truncate({path, size}) {
// TODO: weird case if they truncate while the file is open
// (but `echo hi > foo.txt`, the main thing I care about, uses
// O_TRUNC which thankfully doesn't do that)
let arr = toUtf8Array(await getData(path));
if (size !== arr.length) {
const newArr = new Uint8Array(size);
newArr.set(arr.slice(0, Math.min(size, arr.length)));
arr = newArr;
}
await setData(path, utf8ArrayToString(arr)); return {};
function toUtf8Array(stringOrArray) {
if (typeof stringOrArray == 'string') { return stringToUtf8Array(stringOrArray); }
else { return stringOrArray; }
}
});
return (getData, setData) => ({
// getData: (req: Request U Vars) -> Promise<contentsOfFile: String|Uint8Array>
// setData [optional]: (req: Request U Vars, newContentsOfFile: String) -> Promise<>
// You can override file operations (like `truncate` or `getattr`)
// in the returned set if you want different behavior from what's
// defined here.
async getattr(req) {
return {
st_mode: unix.S_IFREG | 0444 | (setData ? 0222 : 0),
st_nlink: 1,
// you'll want to override this if getData() is slow, because
// getattr() gets called a lot more cavalierly than open().
st_size: toUtf8Array(await getData(req)).length
};
},
// We call getData() once when the file is opened, then cache that
// data for all subsequent reads from that application.
async open(req) {
const data = !(req.flags & unix.O_TRUNC) ? await getData(req) : "";
return { fh: Cache.storeObject(toUtf8Array(data)) };
},
async read({fh, size, offset}) {
return { buf: String.fromCharCode(...Cache.getObjectForHandle(fh).slice(offset, offset + size)) }
},
async write(req) {
const {fh, offset, buf} = req;
let arr = Cache.getObjectForHandle(fh);
const bufarr = stringToUtf8Array(buf);
if (offset + bufarr.length > arr.length) {
const newArr = new Uint8Array(offset + bufarr.length);
newArr.set(arr.slice(0, Math.min(offset, arr.length)));
arr = newArr;
Cache.setObjectForHandle(fh, arr);
}
arr.set(bufarr, offset);
// I guess caller should override write() if they want to actually
// patch and not just re-set the whole string (for example,
// if they want to hot-reload just one function the user modified)
await setData(req, utf8ArrayToString(arr)); return { size: bufarr.length };
},
async release({fh}) { Cache.removeObjectForHandle(fh); return {}; },
async truncate(req) {
// TODO: weird case if they truncate while the file is open
// (but `echo hi > foo.txt`, the main thing I care about, uses
// O_TRUNC which thankfully doesn't do that)
let arr = toUtf8Array(await getData(req));
if (req.size !== arr.length) {
const newArr = new Uint8Array(req.size);
newArr.set(arr.slice(0, Math.min(req.size, arr.length)));
arr = newArr;
}
await setData(req, utf8ArrayToString(arr)); return {};
}
});
})();
const Routes = {};
@ -183,10 +187,12 @@ Routes["/tabs/by-id"] = {
// echo true > mnt/tabs/by-id/1644/active
// cat mnt/tabs/by-id/1644/active
Routes["/tabs/by-id/#TAB_ID/active"] = withTab(tab => JSON.stringify(tab.active) + '\n',
// WEIRD: we do startsWith because you might end up with buf
// being "truee" (if it was "false", then someone wrote "true")
buf => ({ active: buf.startsWith("true") }));
Routes["/tabs/by-id/#TAB_ID/active"] = withTab(
tab => JSON.stringify(tab.active) + '\n',
// WEIRD: we do startsWith because you might end up with buf
// being "truee" (if it was "false", then someone wrote "true")
buf => ({ active: buf.startsWith("true") })
);
})();
(function() {
const evals = {};