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      1 /*
      2  * Copyright (C) 2018 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License
     15  */
     16 
     17 package com.android.dialer.commandline;
     18 
     19 import android.support.annotation.Nullable;
     20 import com.android.dialer.commandline.Command.IllegalCommandLineArgumentException;
     21 import com.google.auto.value.AutoValue;
     22 import com.google.common.collect.ImmutableList;
     23 import com.google.common.collect.ImmutableMap;
     24 import com.google.common.collect.Iterators;
     25 import com.google.common.collect.PeekingIterator;
     26 import com.google.common.collect.UnmodifiableIterator;
     27 
     28 /**
     29  * Parses command line arguments into optional flags (--foo, --key=value, --key value) and required
     30  * positionals (which must be passed in order). Flags must start with "--" and are always before
     31  * positionals. If flags are used "--" must be placed before positionals.
     32  *
     33  * <p>--flag will be interpreted as --flag=true, and --noflag as --flag=false
     34  *
     35  * <p>Grammar:<br>
     36  * dialer-cmd.py <cmd> <args><br>
     37  * <args> = (<flags> -- <positionals>) | <positionals><br>
     38  * <flags> = "no"?<name>(<separator><value>)?<br>
     39  * <separator> = " " | "="
     40  */
     41 @AutoValue
     42 public abstract class Arguments {
     43 
     44   public static final Arguments EMPTY =
     45       new AutoValue_Arguments(ImmutableMap.of(), ImmutableList.of());
     46 
     47   public abstract ImmutableMap<String, String> getFlags();
     48 
     49   public abstract ImmutableList<String> getPositionals();
     50 
     51   /**
     52    * Return the positional at {@code position}. Throw {@link IllegalCommandLineArgumentException} if
     53    * it is absent and reports to the user {@code name} is expected.
     54    */
     55   public String expectPositional(int position, String name)
     56       throws IllegalCommandLineArgumentException {
     57     if (getPositionals().size() <= position) {
     58       throw new IllegalCommandLineArgumentException(name + " expected");
     59     }
     60     return getPositionals().get(position);
     61   }
     62 
     63   public Boolean getBoolean(String flag, boolean defaultValue)
     64       throws IllegalCommandLineArgumentException {
     65     if (!getFlags().containsKey(flag)) {
     66       return defaultValue;
     67     }
     68     switch (getFlags().get(flag)) {
     69       case "true":
     70         return true;
     71       case "false":
     72         return false;
     73       default:
     74         throw new IllegalCommandLineArgumentException("boolean value expected for " + flag);
     75     }
     76   }
     77 
     78   public static Arguments parse(@Nullable String[] rawArguments)
     79       throws IllegalCommandLineArgumentException {
     80     if (rawArguments == null) {
     81       return EMPTY;
     82     }
     83     return parse(Iterators.forArray(rawArguments));
     84   }
     85 
     86   public static Arguments parse(Iterable<String> rawArguments)
     87       throws IllegalCommandLineArgumentException {
     88     return parse(Iterators.unmodifiableIterator(rawArguments.iterator()));
     89   }
     90 
     91   public static Arguments parse(UnmodifiableIterator<String> iterator)
     92       throws IllegalCommandLineArgumentException {
     93     PeekingIterator<String> peekingIterator = Iterators.peekingIterator(iterator);
     94     ImmutableMap<String, String> flags = parseFlags(peekingIterator);
     95     ImmutableList<String> positionals = parsePositionals(peekingIterator);
     96 
     97     return new AutoValue_Arguments(flags, positionals);
     98   }
     99 
    100   private static ImmutableMap<String, String> parseFlags(PeekingIterator<String> iterator)
    101       throws IllegalCommandLineArgumentException {
    102     ImmutableMap.Builder<String, String> flags = ImmutableMap.builder();
    103     if (!iterator.hasNext()) {
    104       return flags.build();
    105     }
    106     if (!iterator.peek().startsWith("--")) {
    107       return flags.build();
    108     }
    109 
    110     while (iterator.hasNext()) {
    111       String peek = iterator.peek();
    112       if (peek.equals("--")) {
    113         iterator.next();
    114         return flags.build();
    115       }
    116       if (peek.startsWith("--")) {
    117         String key = iterator.next().substring(2);
    118         String value;
    119         if (iterator.hasNext() && !iterator.peek().startsWith("--")) {
    120           value = iterator.next();
    121         } else if (key.contains("=")) {
    122           String[] entry = key.split("=", 2);
    123           key = entry[0];
    124           value = entry[1];
    125         } else if (key.startsWith("no")) {
    126           key = key.substring(2);
    127           value = "false";
    128         } else {
    129           value = "true";
    130         }
    131         flags.put(key, value);
    132       } else {
    133         throw new IllegalCommandLineArgumentException("flag or '--' expected");
    134       }
    135     }
    136     return flags.build();
    137   }
    138 
    139   private static ImmutableList<String> parsePositionals(PeekingIterator<String> iterator) {
    140     ImmutableList.Builder<String> positionals = ImmutableList.builder();
    141     positionals.addAll(iterator);
    142     return positionals.build();
    143   }
    144 }
    145