147 lines
3.9 KiB
Go
147 lines
3.9 KiB
Go
/* SHS: Syntactically Homogeneous Shell
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* Copyright (C) 2019 Aidan Hahn
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package ast
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import (
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"os"
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"fmt"
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"math"
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"strconv"
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"strings"
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"gitlab.com/whom/shs/log"
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)
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/* defines whether or not to synchronize tokens wiht os environment vars
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* will not sync non stringable tokens
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*/
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var SyncTablesWithOSEnviron = false
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/* mapping of key to token.
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*/
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type VarTable *map[string]*Token
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/* retrieve the token cooresponding to a given key
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* if SyncTablesWithOSEnviron is true and no token exists for a key
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* os Environment variables will be searched for the key
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*/
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func GetVar(arg string, vt VarTable) *Token {
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val, ok := (*vt)[arg]
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if !ok {
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if !SyncTablesWithOSEnviron {
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return nil
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}
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e := os.Getenv(arg)
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if e != "" {
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t := &Token{inner: e}
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if StrIsNumber(e) {
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t.Tag = NUMBER
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} else {
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t.Tag = STRING
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}
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SetVar(arg, t, vt)
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return t
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}
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return nil
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}
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return val
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}
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/* adds a key->token mapping to the table
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* if SyncTablesWithOSEnviron is true, will also add value to os environment
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* will not do so for non stringable tokens
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*/
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func SetVar(variable string, value *Token, vt VarTable) {
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(*vt)[variable] = value
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if SyncTablesWithOSEnviron &&
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(value.Tag == NUMBER || value.Tag == STRING) {
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token := value.Value()
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if value.Tag == NUMBER {
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// make sure its an int
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a, err := strconv.ParseFloat(token, 64)
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if err == nil && math.Mod(a, 1.0) == 0 {
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token = fmt.Sprintf("%d", int(a))
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}
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}
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os.Setenv(variable, token)
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}
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}
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/* lists all vars in tables
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*/
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func ListVars(vt VarTable) []string {
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keys := make([]string, len(*vt))
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i := 0
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for k := range *vt {
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keys[i] = k
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}
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return keys
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}
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/* if SyncTablesWithOSEnviron is true
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* function will put ever environment variable into VarTable
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*/
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func InitVarTable(table VarTable) {
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if !SyncTablesWithOSEnviron {
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return
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}
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for _, val := range os.Environ() {
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variable := strings.Split(val, "=")
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t := &Token{inner: variable[1]}
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if StrIsNumber(variable[1]) {
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t.Tag = NUMBER
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} else {
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t.Tag = STRING
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}
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if variable[0] == "HOME" {
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SetVar("~", t, table)
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}
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SetVar(variable[0], t, table)
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}
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}
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// Dont do this on var tables youve already called InitVarTable on.... please....
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// This will pull currently contained variables OUT of the operating env
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func DeleteVarTable(table VarTable) {
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for key, _ := range (*table) {
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// from what I can tell, theres not much we can do if this fails
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err := os.Unsetenv(key)
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if err != nil {
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log.Log(log.DEBUG, "Failed to remove " + key + " from env: " + err.Error(), "vartable")
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}
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}
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}
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a
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/* removes var from vartable
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* if SyncTablesWithOSENviron is true, also unsets environment variable
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*/
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func RemoveVar(arg string, table VarTable) {
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if SyncTablesWithOSEnviron {
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err := os.Unsetenv(arg)
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if err != nil {
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log.Log(log.DEBUG,
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"Failed to remove "+arg+" from env: "+err.Error(),
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"vartable")
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}
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}
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delete(*table, arg)
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}
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