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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 | 1x 1x 1x 1x 1x 4x 4x 4x 4x 4x | import { Logger } from "../../../logger";
import { IRequest } from "../../../server/request";
import { DataType } from "../../data/data-type";
import { Database } from "../../data/database";
import { DatabaseValue } from "../../data/database-value";
import { RedisToken } from "../../protocol/redis-token";
import { IRespCommand } from "../resp-command";
/**
* ### Available since 1.0.0.
*
* ### LREM key count element
*
* Removes the first count occurrences of elements equal to element from the list stored at key.
* The count argument influences the operation in the following ways:
*
* - count > 0: Remove elements equal to element moving from head to tail.
* - count < 0: Remove elements equal to element moving from tail to head.
* - count = 0: Remove all elements equal to element.
*
* For example, LREM list -2 "hello" will remove the last two occurrences of "hello" in the
* list stored at list.
*
* Note that non-existing keys are treated like empty lists, so when key does not exist, the
* command will always return 0.
*
* ### Return value
* Integer reply: the number of removed elements.
* ### Examples
* ```
* redis> RPUSH mylist "hello"
* (integer) 1
* redis> RPUSH mylist "hello"
* (integer) 2
* redis> RPUSH mylist "foo"
* (integer) 3
* redis> RPUSH mylist "hello"
* (integer) 4
* redis> LREM mylist -2 "hello"
* (integer) 2
* redis> LRANGE mylist 0 -1
* 1) "hello"
* 2) "foo"
* redis>
* ```
*/
export class LRemCommand extends IRespCommand {
public DbDataType = DataType.LIST
public maxParams = 3
public minParams = 3
public name = "lrem"
private logger: Logger = new Logger(module.id);
public execSync(request: IRequest, db: Database): RedisToken {
this.logger.debug(
`${request.getCommand()}.execute(%s)`,
...request.getParams()
);
let result: number = 0;
const key: string = request.getParam(0),
list: DatabaseValue = db.get(key);
this.logger.debug(`Getting list "${key}"`);
const count: any = Number(request.getParam(1));
this.logger.debug(`Evaluating count: ${request.getParam(1)} = ${count}`);
if (isNaN(count) || count !== parseInt(
String(count),
10
)) {
this.logger.debug("Invalid count value");
return RedisToken.error("ERR value is not an integer or out of range");
} else if (!list) {
this.logger.debug(`LIST ${key} does not exist. Returning ${result}`);
return RedisToken.integer(result);
}
const value: string = request.getParam(2),
matching: number[] = [];
for (let index = 0; index < list.getList().length; index++) {
if (list.getList()[index] === value) {
matching.push(index);
}
}
this.logger.debug(
"Matching elements found at indices: %j",
`${matching}`
);
const toremove: number[] = [];
// Tslint:disable-next-line
for (let index = 0; index < matching.length; index++) {
let remove: boolean = false;
switch (true) {
case count > 0:
remove = true;
break;
case count < 0:
if (matching[index] >= matching.length + count) {
this.logger.debug(`COUNT < 0: if ${matching[index]} >= ${matching.length} + ${count} - remove element ${list.getList()[matching[index]]}`);
remove = true;
}
break;
default:
// Remove all matching elements
remove = true;
}
if (remove) {
// List.getList().splice(Number(matching[index]), 1);
toremove.push(matching[index]);
if (count !== 0 && Math.abs(count) === toremove.length) {
break;
}
}
}
this.logger.debug(
`Removing elements [${toremove.join(",")}] like "${value}" from [%s]`,
...list.getList()
);
while (toremove.length) {
const item = toremove.pop();
this.logger.debug(`Remove item ${item}: ${list.getList()[Number(item)]}`);
list.getList().splice(
Number(item),
1
);
result++;
}
this.logger.debug(`Removed ${result} elements from key "${key}"`);
if (list.getList().length > 0) {
const check: DatabaseValue = db.put(
key,
list
);
this.logger.debug(
"The final list is [%s]",
...check.getList()
);
} else {
db.remove(key);
this.logger.debug(`ZERO length list ${key} removed from the db`);
}
return RedisToken.integer(result);
}
}
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