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authorhuman <human@neet.fi>2021-01-07 16:31:52 +0200
committerhuman <human@neet.fi>2021-01-11 10:25:57 +0200
commita7ab34ebbce60f2af159f9010a2e3629756af3d1 (patch)
tree265c2026e52d8faee189b9a96c18b77557d427cb /extension
parent6d65a48d4e5fbd467c68f6e98301cf136115c570 (diff)
fix truncating in defineFile()
- in the C part: enable FUSE_CAP_ATOMIC_O_TRUNC so that open() will get called with O_TRUNC in flags instead of truncate() being called separately - this also prevents truncate() from calling setData() with an empty string when a file is opened with O_TRUNC - in defineFile()->open(): if O_TRUNC is used, don't call getData() but start with an empty file as if it had just been truncated - in defineFile()->write()/truncate(): correct buffer resizing/copying
Diffstat (limited to 'extension')
-rw-r--r--extension/background.js22
1 files changed, 16 insertions, 6 deletions
diff --git a/extension/background.js b/extension/background.js
index 179a2b8..127f4f9 100644
--- a/extension/background.js
+++ b/extension/background.js
@@ -19,6 +19,9 @@ const unix = {
S_IFREG: 0100000, // regular
S_IFLNK: 0120000, // symbolic link
S_IFSOCK: 0140000, // socket
+
+ // Open flags
+ O_TRUNC: 01000,
}
class UnixError extends Error {
@@ -110,6 +113,7 @@ const Cache = {
return handle;
},
getObjectForHandle(handle) { return this.store[handle]; },
+ setObjectForHandle(handle, object) { this.store[handle] = object; },
removeObjectForHandle(handle) { delete this.store[handle]; }
};
function toUtf8Array(stringOrArray) {
@@ -141,7 +145,10 @@ const defineFile = (getData, setData) => ({
// We call getData() once when the file is opened, then cache that
// data for all subsequent reads from that application.
- async open({path}) { return { fh: Cache.storeObject(toUtf8Array(await getData(path))) }; },
+ async open({path, flags}) {
+ const data = !(flags & unix.O_TRUNC) ? await getData(path) : "";
+ return { fh: Cache.storeObject(toUtf8Array(data)) };
+ },
async read({path, fh, size, offset}) {
return { buf: String.fromCharCode(...Cache.getObjectForHandle(fh).slice(offset, offset + size)) }
},
@@ -150,9 +157,11 @@ const defineFile = (getData, setData) => ({
const bufarr = stringToUtf8Array(buf);
if (offset + bufarr.length > arr.length) {
const newArr = new Uint8Array(offset + bufarr.length);
- newArr.set(arr); arr = newArr;
+ newArr.set(arr.slice(0, Math.min(offset, arr.length)));
+ arr = newArr;
+ Cache.setObjectForHandle(fh, arr);
}
- for (let i = 0; i < bufarr.length; i++) { arr[offset + i] = bufarr[i]; }
+ 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)
@@ -165,11 +174,12 @@ const defineFile = (getData, setData) => ({
// (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) {
+ if (size !== arr.length) {
const newArr = new Uint8Array(size);
- newArr.set(arr); arr = newArr;
+ newArr.set(arr.slice(0, Math.min(size, arr.length)));
+ arr = newArr;
}
- await setData(path, utf8ArrayToString(arr.slice(0, size))); return {};
+ await setData(path, utf8ArrayToString(arr)); return {};
}
});