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prototypes for lumia idb changes (removing array keys, etc ...)

This commit is contained in:
Bruno Windels 2019-06-26 22:09:46 +02:00
parent 59a303daa0
commit 4b17871322
5 changed files with 296 additions and 0 deletions
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30
prototypes/base256.html Normal file
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<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<script type="text/javascript">
function encodeNumber(n) {
const a = (n & 0xFFFF);
const b = (n & 0xFFFF0000) >> 16;
const c = (n & 0xFFFF00000000) >> 32;
const d = (n & 0xFFFF000000000000) >> 48;
return String.fromCharCode(a, b, c, d);
}
function printN(n) {
//document.write(`<p>fn(${n}) = ${encodeNumber(n)}</p>`);
console.log(n, encodeNumber(n));
}
printN(0);
printN(9);
printN(1000);
printN(Number.MAX_SAFE_INTEGER);
</script>
</body>
</html>

110
prototypes/idb-cmp-numbers.html Normal file
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<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style type="text/css">
pre {
font-family: monospace;
display: block;
white-space: pre;
font-size: 2em;
}
</style>
</head>
<body>
<script type="text/javascript">
const MIN = 0;
const MAX = 0xFFFFFFFF;
function zeropad(a, n) {
return "0".repeat(n - a.length) + a;
}
// const encodeNumber = n => zeropad((n >>> 0).toString(16), 8);
function encodeNumber(n) {
const a = (n & 0xFFFF0000) >>> 16;
const b = (n & 0xFFFF) >>> 0;
//return zeropad(a.toString(16), 4) + zeropad(b.toString(16), 4);
return String.fromCharCode(a, b);
}
function decodeNumber(s) {
const a = s.charCodeAt(0);
const b = s.charCodeAt(1);
//return `${a.toString(16)} ${b}`;
return ((a << 16) | b) >>> 0;
}
function formatArg(a) {
if (typeof a === "string") {
return `"${a}"`;
}
if (Array.isArray(a)) {
return `[${a.map(formatArg)}]`;
}
return a+"";
}
function cmp(a, b) {
let value;
try {
const result = indexedDB.cmp(encodeNumber(a), encodeNumber(b));
if (result < 0) {
value = "a < b";
} else if (result === 0) {
value = "a = b";
} else if (result > 0) {
value = "a > b";
}
} catch(err) {
value = err.message;
}
return `cmp(${formatArg(a)} as ${formatArg(encodeNumber(a))},\n ${formatArg(b)} as ${formatArg(encodeNumber(b))}): ${value}`;
}
try {
const tests = [
// see https://stackoverflow.com/questions/28413947/space-efficient-way-to-encode-numbers-as-sortable-strings
// need to encode numbers with base 256 and zero padded at start
// should still fit in 8 bytes then?
(cmp) => cmp(9, 100000),
(cmp) => cmp(1, 2),
(cmp) => cmp(MIN, 1),
(cmp) => cmp(MIN, MIN),
(cmp) => cmp(MIN, MAX),
(cmp) => cmp(MAX >>> 1, MAX),
(cmp) => cmp(0x7fffffff, 0xffff7fff),
(cmp) => cmp(MAX, MAX),
(cmp) => cmp(MAX - 1, MAX),
];
for (const fn of tests) {
const txt = document.createTextNode(fn(cmp));
const p = document.createElement("pre");
p.appendChild(txt);
document.body.appendChild(p);
}
} catch(err) {
alert(err.message);
}
let prev;
for (let i = MIN; i <= MAX; i += 100) {
if (decodeNumber(encodeNumber(i)) !== i) {
document.write(`<p>${i} decodes back to ${decodeNumber(encodeNumber(i))}</p>`);
break;
}
if (typeof prev === "number") {
if (indexedDB.cmp(encodeNumber(prev), encodeNumber(i)) >= 0) {
document.write(`<p>${i} <= ${prev}</p>`);
break;
}
}
prev = i;
}
document.write(`<p>check from ${MIN} to ${prev}</p>`);
</script>
</body>
</html>

76
prototypes/idb-cmp.html Normal file
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<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<style type="text/css">
pre {
font-family: "courier";
display: block;
white-space: pre;
}
</style>
</head>
<body>
<script type="text/javascript">
function encodeNumber(n) {
const a = (n & 0xFFFF);
const b = (n & 0xFFFF0000) >> 16;
const c = (n & 0xFFFF00000000) >> 32;
const d = (n & 0xFFFF000000000000) >> 48;
return String.fromCharCode(a, b, c, d);
}
function formatArg(a) {
if (typeof a === "string") {
return `"${a}"`;
}
if (Array.isArray(a)) {
return `[${a.map(formatArg)}]`;
}
return a+"";
}
function cmp(a, b) {
let value;
try {
const result = indexedDB.cmp(encodeNumber(a), encodeNumber(b));
if (result < 0) {
value = "a < b";
} else if (result === 0) {
value = "a = b";
} else if (result > 0) {
value = "a > b";
}
} catch(err) {
value = err.message;
}
return `cmp(${formatArg(a)},\n ${formatArg(b)}): ${value}`;
}
try {
const tests = [
(cmp) => cmp(Number.MIN_SAFE_INTEGER, Number.MAX_SAFE_INTEGER),
(cmp) => cmp([Number.MIN_SAFE_INTEGER], [Number.MAX_SAFE_INTEGER]),
// see https://stackoverflow.com/questions/28413947/space-efficient-way-to-encode-numbers-as-sortable-strings
// need to encode numbers with base 256 and zero padded at start
// should still fit in 8 bytes then?
(cmp) => cmp("foo-9", "foo-10000"),
(cmp) => cmp("foo-\u0000", "foo-\uFFFF"),
(cmp) => cmp("foo-\u0000", "foo-0"),
(cmp) => cmp("foo-" + Number.MAX_SAFE_INTEGER, "foo-\uFFFF"),
(cmp) => cmp("!abc:host.tld,"+Number.MIN_SAFE_INTEGER, "!abc:host.tld,"+(Number.MIN_SAFE_INTEGER + 1)),
(cmp) => cmp("!abc:host.tld,"+0, "!abc:host.tld,"+(Number.MAX_SAFE_INTEGER)),
(cmp) => cmp("!abc:host.tld,"+Math.floor(Number.MAX_SAFE_INTEGER / 2), "!abc:host.tld,"+(Number.MAX_SAFE_INTEGER)),
];
for (const fn of tests) {
const txt = document.createTextNode(fn(cmp));
const p = document.createElement("pre");
p.appendChild(txt);
document.body.appendChild(p);
}
} catch(err) {
alert(err.message);
}
</script>
</body>
</html>

5
prototypes/idb-continue-key.html
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<head><meta charset="utf-8"></head>
<body>
<script type="text/javascript">
console.log = (...params) => {
document.write(params.join(" ")+"<br>");
};
function reqAsPromise(req) {
return new Promise((resolve, reject) => {
req.onsuccess = () => resolve(req);

75
prototypes/idb-multi-key.html Normal file
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<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
</head>
<body>
<script type="text/javascript">
function reqAsPromise(req) {
return new Promise((resolve, reject) => {
req.onsuccess = () => resolve(req);
req.onerror = (err) => reject(err);
});
}
class Storage {
constructor(databaseName) {
this._databaseName = databaseName;
this._database = null;
}
async open() {
const req = window.indexedDB.open(this._databaseName);
req.onupgradeneeded = (ev) => {
const db = ev.target.result;
const oldVersion = ev.oldVersion;
this._createStores(db, oldVersion);
};
await reqAsPromise(req);
this._database = req.result;
}
_createStores(db) {
db.createObjectStore("files", {keyPath: ["idName"]});
}
async storeFoo(id, name) {
const tx = this._database.transaction(["files"], "readwrite");
const store = tx.objectStore("files");
await reqAsPromise(store.add(value(id, name)));
}
}
function value(id, name) {
return {idName: key(id, name)};
}
function key(id, name) {
return id+","+name;
}
async function main() {
let storage = new Storage("idb-multi-key2");
try {
await storage.open();
await storage.storeFoo(5, "foo");
await storage.storeFoo(6, "bar");
alert("all good");
} catch(err) {
alert(err.message);
}
try {
const result = indexedDB.cmp(key(5, "foo"), key(6, "bar"));
//IDBKeyRange.bound(["aaa", "111"],["zzz", "999"], false, false);
alert("all good: " + result);
} catch (err) {
alert(`IDBKeyRange.bound: ${err.message}`);
}
}
main();
</script>
</body>
</html>