[packager] Optimize archive accesses.

python/mozbuild/mozpack/packager/unpack.py

@@ -54,7 +54,7 @@ class UnpackFinder(BaseFinder):
         self.omnijar = None
         self.jarlogs = {}
         self.optimizedjars = False
-        self.compressed = True
+        self.compressed = False
 
         jars = set()
 
@@ -146,8 +146,7 @@ class UnpackFinder(BaseFinder):
         jar = JarReader(fileobj=file.open())
         if jar.is_optimized:
             self.optimizedjars = True
-        if not any(f.compressed for f in jar):
-            self.compressed = False
+        self.compressed = max(self.compressed, jar.compression)
         if jar.last_preloaded:
             jarlog = jar.entries.keys()
             self.jarlogs[path] = jarlog[:jarlog.index(jar.last_preloaded) + 1]