Profile: Parse config file to a string per attribute

This parser should be able to handle any valid WireGuard or wg-quick
configuration file. It separates the file into a single interface object
and a peer object for each peer. All "[Interface]" sections in the file
are combined into the one object.

For now, later lines in a block with the same key overwrite earlier
lines. This is only relevant for attributes that are lists, such as
Address and AllowedIPs, where additional lines may be expected to append
to the list.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

app/src/main/java/com/wireguard/config/Attribute.java

@@ -0,0 +1,57 @@
+package com.wireguard.config;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * The set of valid attributes for an interface or peer in a WireGuard configuration file.
+ */
+
+enum Attribute {
+    ADDRESS("Address"),
+    ALLOWED_IPS("AllowedIPs"),
+    DNS("DNS"),
+    ENDPOINT("Endpoint"),
+    LISTEN_PORT("ListenPort"),
+    MTU("MTU"),
+    PERSISTENT_KEEPALIVE("PersistentKeepalive"),
+    PRIVATE_KEY("PrivateKey"),
+    PUBLIC_KEY("PublicKey");
+
+    private static final Map<String, Attribute> map;
+
+    static {
+        map = new HashMap<>(Attribute.values().length);
+        for (Attribute key : Attribute.values())
+            map.put(key.getToken(), key);
+    }
+
+    public static Attribute match(String line) {
+        return map.get(line.split("\\s|=")[0]);
+    }
+
+    private final String token;
+    private final Pattern pattern;
+
+    Attribute(String token) {
+        this.pattern = Pattern.compile(token + "\\s*=\\s*(\\S.*)");
+        this.token = token;
+    }
+
+    public String composeWith(String value) {
+        return token + " = " + value + "\n";
+    }
+
+    public String getToken() {
+        return token;
+    }
+
+    public String parseFrom(String line) {
+        final Matcher matcher = pattern.matcher(line);
+        if (matcher.matches())
+            return matcher.group(1);
+        return null;
+    }
+}

app/src/main/java/com/wireguard/config/Interface.java

@@ -0,0 +1,99 @@
+package com.wireguard.config;
+
+import android.databinding.BaseObservable;
+import android.databinding.Bindable;
+import android.databinding.Observable;
+
+import com.wireguard.android.BR;
+
+/**
+ * Represents the configuration for a WireGuard interface (an [Interface] block).
+ */
+
+public class Interface extends BaseObservable implements Observable {
+    private String address;
+    private String dns;
+    private String listenPort;
+    private String mtu;
+    private String privateKey;
+
+    @Bindable
+    public String getAddress() {
+        return address;
+    }
+
+    @Bindable
+    public String getDns() {
+        return dns;
+    }
+
+    @Bindable
+    public String getListenPort() {
+        return listenPort;
+    }
+
+    @Bindable
+    public String getMtu() {
+        return mtu;
+    }
+
+    @Bindable
+    public String getPrivateKey() {
+        return privateKey;
+    }
+
+    public void parseFrom(String line) {
+        final Attribute key = Attribute.match(line);
+        if (key == Attribute.ADDRESS)
+            address = key.parseFrom(line);
+        else if (key == Attribute.DNS)
+            dns = key.parseFrom(line);
+        else if (key == Attribute.LISTEN_PORT)
+            listenPort = key.parseFrom(line);
+        else if (key == Attribute.MTU)
+            mtu = key.parseFrom(line);
+        else if (key == Attribute.PRIVATE_KEY)
+            privateKey = key.parseFrom(line);
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+        notifyPropertyChanged(BR.address);
+    }
+
+    public void setDns(String dns) {
+        this.dns = dns;
+        notifyPropertyChanged(BR.dns);
+    }
+
+    public void setListenPort(String listenPort) {
+        this.listenPort = listenPort;
+        notifyPropertyChanged(BR.listenPort);
+    }
+
+    public void setMtu(String mtu) {
+        this.mtu = mtu;
+        notifyPropertyChanged(BR.mtu);
+    }
+
+    public void setPrivateKey(String privateKey) {
+        this.privateKey = privateKey;
+        notifyPropertyChanged(BR.privateKey);
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder sb = new StringBuilder().append("[Interface]\n");
+        if (address != null)
+            sb.append(Attribute.ADDRESS.composeWith(address));
+        if (dns != null)
+            sb.append(Attribute.DNS.composeWith(dns));
+        if (listenPort != null)
+            sb.append(Attribute.LISTEN_PORT.composeWith(listenPort));
+        if (mtu != null)
+            sb.append(Attribute.MTU.composeWith(mtu));
+        if (privateKey != null)
+            sb.append(Attribute.PRIVATE_KEY.composeWith(privateKey));
+        return sb.toString();
+    }
+}

app/src/main/java/com/wireguard/config/Peer.java

@@ -0,0 +1,83 @@
+package com.wireguard.config;
+
+import android.databinding.BaseObservable;
+import android.databinding.Bindable;
+import android.databinding.Observable;
+
+import com.android.databinding.library.baseAdapters.BR;
+
+/**
+ * Represents the configuration for a WireGuard peer (a [Peer] block).
+ */
+
+public class Peer extends BaseObservable implements Observable {
+    private String allowedIPs;
+    private String endpoint;
+    private String persistentKeepalive;
+    private String publicKey;
+
+    @Bindable
+    public String getAllowedIPs() {
+        return allowedIPs;
+    }
+
+    @Bindable
+    public String getEndpoint() {
+        return endpoint;
+    }
+
+    @Bindable
+    public String getPersistentKeepalive() {
+        return persistentKeepalive;
+    }
+
+    @Bindable
+    public String getPublicKey() {
+        return publicKey;
+    }
+
+    public void parseFrom(String line) {
+        final Attribute key = Attribute.match(line);
+        if (key == Attribute.ALLOWED_IPS)
+            allowedIPs = key.parseFrom(line);
+        else if (key == Attribute.ENDPOINT)
+            endpoint = key.parseFrom(line);
+        else if (key == Attribute.PERSISTENT_KEEPALIVE)
+            persistentKeepalive = key.parseFrom(line);
+        else if (key == Attribute.PUBLIC_KEY)
+            publicKey = key.parseFrom(line);
+    }
+
+    public void setAllowedIPs(String allowedIPs) {
+        this.allowedIPs = allowedIPs;
+        notifyPropertyChanged(BR.allowedIPs);
+    }
+
+    public void setEndpoint(String endpoint) {
+        this.endpoint = endpoint;
+        notifyPropertyChanged(BR.endpoint);
+    }
+
+    public void setPersistentKeepalive(String persistentKeepalive) {
+        this.persistentKeepalive = persistentKeepalive;
+        notifyPropertyChanged(BR.persistentKeepalive);
+    }
+
+    public void setPublicKey(String publicKey) {
+        this.publicKey = publicKey;
+        notifyPropertyChanged(BR.publicKey);
+    }
+
+    public String toString() {
+        final StringBuilder sb = new StringBuilder().append("[Peer]\n");
+        if (allowedIPs != null)
+            sb.append(Attribute.ALLOWED_IPS.composeWith(allowedIPs));
+        if (endpoint != null)
+            sb.append(Attribute.ENDPOINT.composeWith(endpoint));
+        if (persistentKeepalive != null)
+            sb.append(Attribute.PERSISTENT_KEEPALIVE.composeWith(persistentKeepalive));
+        if (publicKey != null)
+            sb.append(Attribute.PUBLIC_KEY.composeWith(publicKey));
+        return sb.toString();
+    }
+}

app/src/main/java/com/wireguard/config/Profile.java

@@ -1,56 +1,65 @@
 package com.wireguard.config;
 
-import android.databinding.BaseObservable;
-import android.databinding.Bindable;
-import android.databinding.Observable;
-
-import com.wireguard.android.BR;
+import android.databinding.ObservableArrayList;
+import android.databinding.ObservableList;
 
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
+import java.nio.charset.StandardCharsets;
 
 /**
  * Represents a wg-quick profile.
  */
 
-public class Profile extends BaseObservable implements Observable {
-    private String config;
+public class Profile {
+    private final Interface iface = new Interface();
     private final String name;
+    private final ObservableList<Peer> peers = new ObservableArrayList<>();
 
     public Profile(String name) {
         this.name = name;
     }
 
-    public void fromStream(InputStream stream)
-            throws IOException {
-        final StringBuilder sb = new StringBuilder(stream.available());
-        String line;
-        try (BufferedReader reader = new BufferedReader(new InputStreamReader(stream))) {
-            while ((line = reader.readLine()) != null)
-                sb.append(line).append('\n');
-        }
-        setConfig(sb.toString());
-    }
-
-    @Bindable
-    public String getConfig() {
-        return config;
+    public Interface getInterface() {
+        return iface;
     }
 
-    @Bindable
     public String getName() {
         return name;
     }
 
-    public void setConfig(String config) {
-        this.config = config;
-        notifyPropertyChanged(BR.config);
+    public ObservableList<Peer> getPeers() {
+        return peers;
+    }
+
+    public void parseFrom(InputStream stream)
+            throws IOException {
+        try (BufferedReader reader = new BufferedReader(
+                new InputStreamReader(stream, StandardCharsets.UTF_8))) {
+            Peer currentPeer = null;
+            String line;
+            while ((line = reader.readLine()) != null) {
+                if (line.equals("[Interface]")) {
+                    currentPeer = null;
+                } else if (line.equals("[Peer]")) {
+                    currentPeer = new Peer();
+                    peers.add(currentPeer);
+                } else if (currentPeer == null) {
+                    iface.parseFrom(line);
+                } else {
+                    currentPeer.parseFrom(line);
+                }
+            }
+        }
     }
 
     @Override
     public String toString() {
-        return getConfig();
+        StringBuilder sb = new StringBuilder().append(iface.toString());
+        for (Peer peer : peers)
+            sb.append(peer.toString());
+        return sb.toString();
     }
 }