Process platform-specific suffixes immediately

In preferences files, platform-specific versions can be indicated by a
.linux, .windows or .macos suffix on the key name. Previously, these
keys were loaded as normal and then afterwards, all keys were scanned
after loading them and any platform-specific versions replaced the
regular ones.

However, this means that these platform-specific versions get an
unexpected form of priority. Normally, when a single key is set twice,
the latter overrides the first. However, the platform-specific values
could override the regular versions, even when the regular version
occurs later in the file.

This problem was particularly confusing when using the new
platform.local.txt: a regular preference in platform.local.txt did not
override a platform-specific preference in platform.txt.

This commit changes behaviour to process these suffixes directly as they
are read from the preference files. If a suffix for the current platform
is found, the line is processed as if the suffix was not present. If a
suffix for another platform is found, the line is ignored altogether.

This can slightly change the way preferences files are parsed, but as
long as platform-specific preferences are defined after the
corresponding regular preferences, the behaviour should be the same.

Author: matthijskooijman

Diff for: app/src/processing/app/helpers/PreferencesMap.java

@@ -77,6 +77,19 @@ public void load(File file) throws IOException {
     load(new FileInputStream(file));
   }
 
+  protected String processPlatformSuffix(String key, String suffix, boolean isCurrentPlatform) {
+    if (key == null)
+      return null;
+    // Key does not end with the given suffix? Process as normal
+    if (!key.endsWith(suffix))
+      return key;
+    // Not the current platform? Ignore this key
+    if (!isCurrentPlatform)
+      return null;
+    // Strip the suffix from the key
+    return key.substring(0, key.length() - suffix.length());
+  }
+
   /**
    * Parse a property list stream and put key/value pairs into the Map
    * 
@@ -91,28 +104,15 @@ public void load(InputStream input) throws IOException {
 
       int equals = line.indexOf('=');
       if (equals != -1) {
-        String key = line.substring(0, equals);
-        String value = line.substring(equals + 1);
-        put(key.trim(), value.trim());
-      }
-    }
+        String key = line.substring(0, equals).trim();
+        String value = line.substring(equals + 1).trim();
 
-    // This is needed to avoid ConcurrentAccessExceptions
-    Set<String> keys = new LinkedHashSet<String>(keySet());
+        key = processPlatformSuffix(key, ".linux", Base.isLinux());
+        key = processPlatformSuffix(key, ".windows", Base.isWindows());
+        key = processPlatformSuffix(key, ".macos", Base.isMacOS());
 
-    // Override keys that have OS specific versions
-    for (String key : keys) {
-      boolean replace = false;
-      if (Base.isLinux() && key.endsWith(".linux"))
-        replace = true;
-      if (Base.isWindows() && key.endsWith(".windows"))
-        replace = true;
-      if (Base.isMacOS() && key.endsWith(".macos"))
-        replace = true;
-      if (replace) {
-        int dot = key.lastIndexOf('.');
-        String overridenKey = key.substring(0, dot);
-        put(overridenKey, get(key));
+        if (key != null)
+          put(key, value);
       }
     }
   }