shm-typed-array
Version:
IPC shared memory for NodeJs. Use as Buffer or TypedArray.
238 lines (220 loc) • 7.96 kB
JavaScript
;
const buildDir = process.env.DEBUG_SHM == 1 ? 'Debug' : 'Release';
const shm = require('./build/' + buildDir + '/shm.node');
const uint32Max = Math.pow(2,32) - 1;
const keyMin = 1;
const keyMax = uint32Max - keyMin;
const lengthMin = 1;
/**
* Max length of shared memory segment (count of elements, not bytes)
*/
const lengthMax = shm.NODE_BUFFER_MAX_LENGTH;
const cleanup = function () {
try {
var cnt = shm.detachAll();
if (cnt > 0)
console.info('shm segments destroyed:', cnt);
} catch(exc) { console.error(exc); }
};
process.on('exit', cleanup);
/**
* Types of shared memory object
*/
const BufferType = {
'Buffer': shm.SHMBT_BUFFER,
'Int8Array': shm.SHMBT_INT8,
'Uint8Array': shm.SHMBT_UINT8,
'Uint8ClampedArray': shm.SHMBT_UINT8CLAMPED,
'Int16Array': shm.SHMBT_INT16,
'Uint16Array': shm.SHMBT_UINT16,
'Int32Array': shm.SHMBT_INT32,
'Uint32Array': shm.SHMBT_UINT32,
'Float32Array': shm.SHMBT_FLOAT32,
'Float64Array': shm.SHMBT_FLOAT64,
};
const BufferTypeSizeof = {
'Buffer': 1,
'Int8Array': 1,
'Uint8Array': 1,
'Uint8ClampedArray': 1,
'Int16Array': 2,
'Uint16Array': 2,
'Int32Array': 4,
'Uint32Array': 4,
'Float32Array': 4,
'Float64Array': 8,
};
/**
* Create System V or POSIX shared memory
* @param {int} count - number of elements
* @param {string} typeKey - see keys of BufferType
* @param {int/string/null} key - integer key for System V shared memory segment, or null to autogenerate,
* or string name for POSIX shared memory object, should start with '/'.
* @param {string} permStr - permissions, default is 660
* @return {mixed/null} shared memory buffer/array object, or null if already exists with provided key
* Class depends on param typeKey: Buffer or descendant of TypedArray.
* For System V: returned object has property 'key' - integer key of created shared memory segment
*/
function create(count, typeKey /*= 'Buffer'*/, key /*= null*/, permStr /*= '660'*/) {
if (typeof key === 'string') {
return createPosix(key, count, typeKey, permStr);
}
if (typeKey === undefined)
typeKey = 'Buffer';
if (key === undefined)
key = null;
if (BufferType[typeKey] === undefined)
throw new Error("Unknown type key " + typeKey);
if (key !== null) {
if (!(Number.isSafeInteger(key) && key >= keyMin && key <= keyMax))
throw new RangeError('Shm key should be ' + keyMin + ' .. ' + keyMax);
}
if (permStr === undefined || isNaN( Number.parseInt(permStr, 8)))
permStr = '660';
const perm = Number.parseInt(permStr, 8);
var type = BufferType[typeKey];
//var size1 = BufferTypeSizeof[typeKey];
//var size = size1 * count;
if (!(Number.isSafeInteger(count) && count >= lengthMin && count <= lengthMax))
throw new RangeError('Count should be ' + lengthMin + ' .. ' + lengthMax);
let res;
if (key) {
res = shm.get(key, count, shm.IPC_CREAT|shm.IPC_EXCL|perm, 0, type);
} else {
do {
key = _keyGen();
res = shm.get(key, count, shm.IPC_CREAT|shm.IPC_EXCL|perm, 0, type);
} while(!res);
}
if (res) {
res.key = key;
}
return res;
}
/**
* Create POSIX shared memory object
* @param {string} name - string name of shared memory object, should start with '/'
* Eg. '/test' will create virtual file '/dev/shm/test' in tmpfs for Linix
* @param {int} count - number of elements
* @param {string} typeKey - see keys of BufferType
* @param {string} permStr - permissions, default is 660
* @return {mixed/null} shared memory buffer/array object, or null if already exists with provided name
* Class depends on param typeKey: Buffer or descendant of TypedArray
*/
function createPosix(name, count, typeKey /*= 'Buffer'*/, permStr /*= '660'*/) {
if (typeKey === undefined)
typeKey = 'Buffer';
if (BufferType[typeKey] === undefined)
throw new Error("Unknown type key " + typeKey);
if (permStr === undefined || isNaN( Number.parseInt(permStr, 8)))
permStr = '660';
const perm = Number.parseInt(permStr, 8);
const type = BufferType[typeKey];
//var size1 = BufferTypeSizeof[typeKey];
//var size = size1 * count;
if (!(Number.isSafeInteger(count) && count >= lengthMin && count <= lengthMax))
throw new RangeError('Count should be ' + lengthMin + ' .. ' + lengthMax);
const oflag = shm.O_CREAT | shm.O_RDWR | shm.O_EXCL;
const mmap_flags = shm.MAP_SHARED;
const res = shm.getPosix(name, count, oflag, perm, mmap_flags, type);
return res;
}
/**
* Get System V/POSIX shared memory
* @param {int/string} key - integer key of System V shared memory segment, or string name of POSIX shared memory object
* @param {string} typeKey - see keys of BufferType
* @return {mixed/null} shared memory buffer/array object, see create(), or null if not exists
*/
function get(key, typeKey /*= 'Buffer'*/) {
if (typeof key === 'string') {
return getPosix(key, typeKey);
}
if (typeKey === undefined)
typeKey = 'Buffer';
if (BufferType[typeKey] === undefined)
throw new Error("Unknown type key " + typeKey);
var type = BufferType[typeKey];
if (!(Number.isSafeInteger(key) && key >= keyMin && key <= keyMax))
throw new RangeError('Shm key should be ' + keyMin + ' .. ' + keyMax);
let res = shm.get(key, 0, 0, 0, type);
if (res) {
res.key = key;
}
return res;
}
/**
* Get POSIX shared memory object
* @param {string} name - string name of shared memory object
* @param {string} typeKey - see keys of BufferType
* @return {mixed/null} shared memory buffer/array object, see createPosix(), or null if not exists
*/
function getPosix(name, typeKey /*= 'Buffer'*/) {
if (typeKey === undefined)
typeKey = 'Buffer';
if (BufferType[typeKey] === undefined)
throw new Error("Unknown type key " + typeKey);
var type = BufferType[typeKey];
const oflag = shm.O_RDWR;
const mmap_flags = shm.MAP_SHARED;
let res = shm.getPosix(name, 0, oflag, 0, mmap_flags, type);
return res;
}
/**
* Detach System V/POSIX shared memory
* For System V: If there are no other attaches for this segment, it will be destroyed
* For POSIX: It will be destroyed only if `forceDestroy` is true
* @param {int/string} key - integer key of System V shared memory segment, or string name of POSIX shared memory object
* @param {bool} forceDestroy - true to destroy even there are other attaches
* @return {int} 0 on destroy, or count of left attaches, or -1 if not exists
*/
function detach(key, forceDestroy /*= false*/) {
if (typeof key === 'string') {
return detachPosix(key, forceDestroy);
}
if (forceDestroy === undefined)
forceDestroy = false;
return shm.detach(key, forceDestroy);
}
/**
* Detach POSIX shared memory object
* @param {string} name - string name of shared memory object
* @param {bool} forceDestroy - true to unlink
* @return {int} 0 on destroy, 1 on detach, -1 if not exists
*/
function detachPosix(name, forceDestroy /*= false*/) {
if (forceDestroy === undefined)
forceDestroy = false;
return shm.detachPosix(name, forceDestroy);
}
/**
* Destroy System V/POSIX shared memory
* @param {int/string} key - integer key of System V shared memory segment, or string name of POSIX shared memory object
* @return {boolean}
*/
function destroy(key) {
return detach(key, true) == 0;
}
/**
* Detach all created and getted shared memory objects (both System V and POSIX)
* Will be automatically called on process exit/termination
* @return {int} count of destroyed System V segments
*/
function detachAll() {
return shm.detachAll();
}
function _keyGen() {
return keyMin + Math.floor(Math.random() * keyMax);
}
//Exports
module.exports.create = create;
module.exports.createPosix = createPosix;
module.exports.get = get;
module.exports.getPosix = getPosix;
module.exports.detach = detach;
module.exports.detachPosix = detachPosix;
module.exports.destroy = destroy;
module.exports.detachAll = detachAll;
module.exports.getTotalSize = shm.getTotalUsedSize;
module.exports.getTotalCreatedSize = shm.getTotalAllocatedSize;
module.exports.BufferType = BufferType;
module.exports.LengthMax = lengthMax;