Add primitive variables

doc/api.md

@@ -26,6 +26,10 @@ The `path` is an array of namespace keys which select a path of namespaces to be
 
 See full_protocol.js for an example of usage.
 
+### ProtoDef.setVariable(name, value)
+
+Sets a primitive variable type for the specified `name`, which can be dynamically updated. Can be refrenced in switch statements with the "/" prefix.
+
 ### ProtoDef.read(buffer, cursor, _fieldInfo, rootNodes)
 
 Read the packet defined by `_fieldInfo` in `buffer` starting from `cursor` using the context `rootNodes`.
@@ -80,6 +84,10 @@ Add types in `protocol` recursively. The protocol object is an object with keys
 
 The `path` is an array of namespace keys which select a path of namespaces to be added to the protodef object.
 
+### ProtoDefCompiler.addVariable(name, value)
+
+Adds a primitive variable type for the specified `name`, which can be dynamically updated. Can be refrenced in switch statements with the "/" prefix.
+
 ### ProtoDefCompiler.compileProtoDefSync(options = { printCode: false })
 
 Compile and return a `ProtoDef` object, optionaly print the generated javascript code.
@@ -94,6 +102,11 @@ sizeOfCtx, writeCtx and readCtx are the compiled version of sizeOf, write and re
 
 It can be used directly for easier debugging/using already compiled js.
 
+### CompiledProtodef.setVariable(name, value)
+
+Sets a primitive variable type for the specified `name`, which can be dynamically updated. Can be refrenced in switch statements with the "/" prefix.
+
+
 ## utils
 
 Some functions that can be useful to build new datatypes reader and writer.

examples/variable.js

@@ -0,0 +1,31 @@
+const { ProtoDef } = require('protodef')
+const assert = require('assert')
+
+// Create a protocol where DrawText is sent with a "opacity" field at the end only if the color isn't transparent.
+const protocol = {
+ string: ['pstring', { countType: 'varint' }],
+ ColorPalette: ['container', [{ name: 'palette', type: ['array', { countType: 'i32', type: 'string' }] }]],
+ DrawText: ['container', [{ name: 'color', type: 'u8' }, { name: 'opacity', type: ['switch', { compareTo: 'color', fields: { '/color_transparent': 'void' }, default: 'u8' }] }]]
+}
+
+function test () {
+ // A "palette" here refers to a array of values, identified with their index in the array
+ const palette = ['red', 'green', 'blue', 'transparent']
+ const proto = new ProtoDef()
+ proto.addTypes(protocol)
+ // A "variable" is similar to a type, it's a primitive value that can be used in switch comparisons.
+ proto.setVariable('color_transparent', palette.indexOf('transparent'))
+ // An example usage is sending paletted IDs, with feild serialization based on those IDs
+ proto.createPacketBuffer('ColorPalette', { palette })
+ // Here, "opacity", 0x4 is written *only* if the color isn't transparent. In this case, it is, so 0x4 isn't written.
+ // At the top is 0x3, the index of the "transparent" color.
+ const s = proto.createPacketBuffer('DrawText', { color: palette.indexOf('transparent'), opacity: 4 })
+ assert(s.equals(Buffer.from([3])))
+ console.log(s)
+
+ // Here 4 should be written at the end
+ const t = proto.createPacketBuffer('DrawText', { color: palette.indexOf('blue'), opacity: 4 })
+ assert(t.equals(Buffer.from([2, 4])))
+}
+
+test()

package.json

@@ -16,7 +16,7 @@
  "dependencies": {
  "lodash.get": "^4.4.2",
  "lodash.reduce": "^4.6.0",
- "protodef-validator": "^1.2.2",
+ "protodef-validator": "^1.3.0",
  "readable-stream": "^3.0.3"
  },
  "engines": {

src/compiler.js

@@ -32,6 +32,12 @@ class ProtoDefCompiler {
  this.sizeOfCompiler.addProtocol(protocolData, path)
  }
 
+ addVariable (key, val) {
+ this.readCompiler.addContextType(key, val)
+ this.writeCompiler.addContextType(key, val)
+ this.sizeOfCompiler.addContextType(key, val)
+ }
+
  compileProtoDefSync (options = { printCode: false }) {
  const sizeOfCode = this.sizeOfCompiler.generate()
  const writeCode = this.writeCompiler.generate()
@@ -70,6 +76,12 @@ class CompiledProtodef {
  return writeFn(value, buffer, cursor)
  }
 
+ setVariable (key, val) {
+ this.sizeOfCtx[key] = val
+ this.readCtx[key] = val
+ this.writeCtx[key] = val
+ }
+
  sizeOf (value, type) {
  const sizeFn = this.sizeOfCtx[type]
  if (!sizeFn) { throw new Error('missing data type: ' + type) }
@@ -186,7 +198,7 @@ class Compiler {
  getField (name) {
  const path = name.split('/')
  let i = this.scopeStack.length - 1
- const reserved = ['value', 'enum', 'default', 'size']
+ const reserved = ['value', 'enum', 'default', 'size', 'offset']
  while (path.length) {
  const scope = this.scopeStack[i]
  const field = path.shift()

src/datatypes/compiler-conditional.js

@@ -10,7 +10,8 @@ module.exports = {
  let code = `switch (${compare}) {\n`
  for (const key in struct.fields) {
  let val = key
- if (isNaN(val) && val !== 'true' && val !== 'false') val = `"${val}"`
+ if (val.startsWith('/')) val = 'ctx.' + val.slice(1) // Root context variable
+ else if (isNaN(val) && val !== 'true' && val !== 'false') val = `"${val}"`
  code += compiler.indent(`case ${val}: return ` + compiler.callType(struct.fields[key])) + '\n'
  }
  code += compiler.indent('default: return ' + compiler.callType(struct.default ? struct.default : 'void')) + '\n'
@@ -39,7 +40,8 @@ module.exports = {
  let code = `switch (${compare}) {\n`
  for (const key in struct.fields) {
  let val = key
- if (isNaN(val) && val !== 'true' && val !== 'false') val = `"${val}"`
+ if (val.startsWith('/')) val = 'ctx.' + val.slice(1) // Root context variable
+ else if (isNaN(val) && val !== 'true' && val !== 'false') val = `"${val}"`
  code += compiler.indent(`case ${val}: return ` + compiler.callType('value', struct.fields[key])) + '\n'
  }
  code += compiler.indent('default: return ' + compiler.callType('value', struct.default ? struct.default : 'void')) + '\n'
@@ -69,7 +71,8 @@ module.exports = {
  let code = `switch (${compare}) {\n`
  for (const key in struct.fields) {
  let val = key
- if (isNaN(val) && val !== 'true' && val !== 'false') val = `"${val}"`
+ if (val.startsWith('/')) val = 'ctx.' + val.slice(1) // Root context variable
+ else if (isNaN(val) && val !== 'true' && val !== 'false') val = `"${val}"`
  code += compiler.indent(`case ${val}: return ` + compiler.callType('value', struct.fields[key])) + '\n'
  }
  code += compiler.indent('default: return ' + compiler.callType('value', struct.default ? struct.default : 'void')) + '\n'

src/datatypes/conditional.js

@@ -8,7 +8,12 @@ module.exports = {
 function readSwitch (buffer, offset, { compareTo, fields, compareToValue, default: defVal }, rootNode) {
  compareTo = compareToValue !== undefined ? compareToValue : getField(compareTo, rootNode)
  if (typeof fields[compareTo] === 'undefined' && typeof defVal === 'undefined') { throw new Error(compareTo + ' has no associated fieldInfo in switch') }
-
+ for (const field in fields) {
+ if (field.startsWith('/')) {
+ fields[this.types[field.slice(1)]] = fields[field]
+ delete fields[field]
+ }
+ }
  const caseDefault = typeof fields[compareTo] === 'undefined'
  const resultingType = caseDefault ? defVal : fields[compareTo]
  const fieldInfo = getFieldInfo(resultingType)
@@ -18,7 +23,12 @@ function readSwitch (buffer, offset, { compareTo, fields, compareToValue, defaul
 function writeSwitch (value, buffer, offset, { compareTo, fields, compareToValue, default: defVal }, rootNode) {
  compareTo = compareToValue !== undefined ? compareToValue : getField(compareTo, rootNode)
  if (typeof fields[compareTo] === 'undefined' && typeof defVal === 'undefined') { throw new Error(compareTo + ' has no associated fieldInfo in switch') }
-
+ for (const field in fields) {
+ if (field.startsWith('/')) {
+ fields[this.types[field.slice(1)]] = fields[field]
+ delete fields[field]
+ }
+ }
  const caseDefault = typeof fields[compareTo] === 'undefined'
  const fieldInfo = getFieldInfo(caseDefault ? defVal : fields[compareTo])
  return tryDoc(() => this.write(value, buffer, offset, fieldInfo, rootNode), caseDefault ? 'default' : compareTo)
@@ -27,7 +37,12 @@ function writeSwitch (value, buffer, offset, { compareTo, fields, compareToValue
 function sizeOfSwitch (value, { compareTo, fields, compareToValue, default: defVal }, rootNode) {
  compareTo = compareToValue !== undefined ? compareToValue : getField(compareTo, rootNode)
  if (typeof fields[compareTo] === 'undefined' && typeof defVal === 'undefined') { throw new Error(compareTo + ' has no associated fieldInfo in switch') }
-
+ for (const field in fields) {
+ if (field.startsWith('/')) {
+ fields[this.types[field.slice(1)]] = fields[field]
+ delete fields[field]
+ }
+ }
  const caseDefault = typeof fields[compareTo] === 'undefined'
  const fieldInfo = getFieldInfo(caseDefault ? defVal : fields[compareTo])
  return tryDoc(() => this.sizeOf(value, fieldInfo, rootNode), caseDefault ? 'default' : compareTo)

src/protodef.js

@@ -103,6 +103,10 @@ class ProtoDef {
  }
  }
 
+ setVariable (key, val) {
+ this.types[key] = val
+ }
+
  read (buffer, cursor, _fieldInfo, rootNodes) {
  const { type, typeArgs } = getFieldInfo(_fieldInfo)
  const typeFunctions = this.types[type]

test/dataTypes/prepareTests.js

@@ -28,11 +28,22 @@ function arrayToBuffer (arr) {
 }
 
 function transformValues (type, values) {
- return values.map(value => ({
- buffer: arrayToBuffer(value.buffer),
- value: type.indexOf('buffer') === 0 ? arrayToBuffer(value.value) : value.value,
- description: value.description
- }))
+ return values.map(val => {
+ let value = val.value
+ if (type.indexOf('buffer') === 0) {
+ value = arrayToBuffer(value)
+ } else if (value) {
+ // we cannot use undefined type in JSON so need to convert it here to pass strictEquals test
+ for (const key in value) {
+ if (value[key] === 'undefined') value[key] = undefined
+ }
+ }
+ return {
+ buffer: arrayToBuffer(val.buffer),
+ value,
+ description: val.description
+ }
+ })
 }
 
 testData.forEach(tests => {
@@ -47,6 +58,7 @@ testData.forEach(tests => {
  types[type] = subtype.type
  compiler.addTypesToCompile(types)
 
+ subtype.vars?.forEach(([k, v]) => { proto.setVariable(k, v); compiler.addVariable(k, v) })
  subtype.values = transformValues(test.type, subtype.values)
  subtype.type = type
  subTypes.push(subtype)