1 files changed, 81 insertions, 0 deletions
diff --git a/libpathod/language/message.py b/libpathod/language/message.py
new file mode 100644
index 00000000..b5ef7045
--- /dev/null
+++ b/libpathod/language/message.py
@@ -0,0 +1,81 @@
+import abc
+from . import actions
+
+LOG_TRUNCATE = 1024
+
+
+class Message(object):
+    __metaclass__ = abc.ABCMeta
+    logattrs = []
+
+    def __init__(self, tokens):
+        self.tokens = tokens
+
+    def toks(self, klass):
+        """
+            Fetch all tokens that are instances of klass
+        """
+        return [i for i in self.tokens if isinstance(i, klass)]
+
+    def tok(self, klass):
+        """
+            Fetch first token that is an instance of klass
+        """
+        l = self.toks(klass)
+        if l:
+            return l[0]
+
+    def length(self, settings):
+        """
+            Calculate the length of the base message without any applied
+            actions.
+        """
+        return sum(len(x) for x in self.values(settings))
+
+    def preview_safe(self):
+        """
+            Return a copy of this message that issafe for previews.
+        """
+        tokens = [i for i in self.tokens if not isinstance(i, actions.PauseAt)]
+        return self.__class__(tokens)
+
+    def maximum_length(self, settings):
+        """
+            Calculate the maximum length of the base message with all applied
+            actions.
+        """
+        l = self.length(settings)
+        for i in self.actions:
+            if isinstance(i, actions.InjectAt):
+                l += len(i.value.get_generator(settings))
+        return l
+
+    @classmethod
+    def expr(klass): # pragma: no cover
+        pass
+
+    def log(self, settings):
+        """
+            A dictionary that should be logged if this message is served.
+        """
+        ret = {}
+        for i in self.logattrs:
+            v = getattr(self, i)
+            # Careful not to log any VALUE specs without sanitizing them first.
+            # We truncate at 1k.
+            if hasattr(v, "values"):
+                v = [x[:LOG_TRUNCATE] for x in v.values(settings)]
+                v = "".join(v).encode("string_escape")
+            elif hasattr(v, "__len__"):
+                v = v[:LOG_TRUNCATE]
+                v = v.encode("string_escape")
+            ret[i] = v
+        ret["spec"] = self.spec()
+        return ret
+
+    def freeze(self, settings):
+        r = self.resolve(settings)
+        return self.__class__([i.freeze(settings) for i in r.tokens])
+
+    def __repr__(self):
+        return self.spec()