Extract signature_trie.py from verify_overlaps.py

Makes the efficient pattern matching of hidden API flags that is used
by verify_overlaps.py available for use in other scripts.

As part of the move this cleans up the python to use consistent quotes,
and fix pylint issues.

Bug: 202154151
Test: m out/soong/hiddenapi/hiddenapi-flags.csv
      atest --host signature_trie_test verify_overlaps_test
      pyformat -s 4 --force_quote_type double -i scripts/hiddenapi/signature_trie*
      /usr/bin/pylint --rcfile $ANDROID_BUILD_TOP/tools/repohooks/tools/pylintrc scripts/hiddenapi/signature_trie*
Change-Id: I758ca70bb5b7e6806f14b72fd04f821a069f188f

Change-Id: I73fdb7e02127a8c0171a285221d9e6024310953d
diff --git a/scripts/hiddenapi/verify_overlaps.py b/scripts/hiddenapi/verify_overlaps.py
index 4cd7e63..e5214df 100755
--- a/scripts/hiddenapi/verify_overlaps.py
+++ b/scripts/hiddenapi/verify_overlaps.py
@@ -13,239 +13,14 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-"""Verify that one set of hidden API flags is a subset of another.
-"""
+"""Verify that one set of hidden API flags is a subset of another."""
 
 import argparse
 import csv
 import sys
 from itertools import chain
 
-#pylint: disable=line-too-long
-class InteriorNode:
-    """An interior node in a trie.
-
-    Each interior node has a dict that maps from an element of a signature to
-    either another interior node or a leaf. Each interior node represents either
-    a package, class or nested class. Class members are represented by a Leaf.
-
-    Associating the set of flags [public-api] with the signature
-    "Ljava/lang/Object;->String()Ljava/lang/String;" will cause the following
-    nodes to be created:
-    Node()
-    ^- package:java -> Node()
-       ^- package:lang -> Node()
-           ^- class:Object -> Node()
-              ^- member:String()Ljava/lang/String; -> Leaf([public-api])
-
-    Associating the set of flags [blocked,core-platform-api] with the signature
-    "Ljava/lang/Character$UnicodeScript;->of(I)Ljava/lang/Character$UnicodeScript;"
-    will cause the following nodes to be created:
-    Node()
-    ^- package:java -> Node()
-       ^- package:lang -> Node()
-           ^- class:Character -> Node()
-              ^- class:UnicodeScript -> Node()
-                 ^- member:of(I)Ljava/lang/Character$UnicodeScript;
-                    -> Leaf([blocked,core-platform-api])
-
-    Attributes:
-        nodes: a dict from an element of the signature to the Node/Leaf
-          containing the next element/value.
-    """
-    #pylint: enable=line-too-long
-
-    def __init__(self):
-        self.nodes = {}
-
-    #pylint: disable=line-too-long
-    def signatureToElements(self, signature):
-        """Split a signature or a prefix into a number of elements:
-        1. The packages (excluding the leading L preceding the first package).
-        2. The class names, from outermost to innermost.
-        3. The member signature.
-        e.g.
-        Ljava/lang/Character$UnicodeScript;->of(I)Ljava/lang/Character$UnicodeScript;
-        will be broken down into these elements:
-        1. package:java
-        2. package:lang
-        3. class:Character
-        4. class:UnicodeScript
-        5. member:of(I)Ljava/lang/Character$UnicodeScript;
-        """
-        # Remove the leading L.
-        #  - java/lang/Character$UnicodeScript;->of(I)Ljava/lang/Character$UnicodeScript;
-        text = signature.removeprefix("L")
-        # Split the signature between qualified class name and the class member
-        # signature.
-        #  0 - java/lang/Character$UnicodeScript
-        #  1 - of(I)Ljava/lang/Character$UnicodeScript;
-        parts = text.split(";->")
-        member = parts[1:]
-        # Split the qualified class name into packages, and class name.
-        #  0 - java
-        #  1 - lang
-        #  2 - Character$UnicodeScript
-        elements = parts[0].split("/")
-        packages = elements[0:-1]
-        className = elements[-1]
-        if className in ("*" , "**"): #pylint: disable=no-else-return
-            # Cannot specify a wildcard and target a specific member
-            if len(member) != 0:
-                raise Exception(
-                    "Invalid signature %s: contains wildcard %s and member " \
-                    "signature %s"
-                    % (signature, className, member[0]))
-            wildcard = [className]
-            # Assemble the parts into a single list, adding prefixes to identify
-            # the different parts.
-            #  0 - package:java
-            #  1 - package:lang
-            #  2 - *
-            return list(
-                chain(["package:" + x for x in packages], wildcard))
-        else:
-            # Split the class name into outer / inner classes
-            #  0 - Character
-            #  1 - UnicodeScript
-            classes = className.split("$")
-            # Assemble the parts into a single list, adding prefixes to identify
-            # the different parts.
-            #  0 - package:java
-            #  1 - package:lang
-            #  2 - class:Character
-            #  3 - class:UnicodeScript
-            #  4 - member:of(I)Ljava/lang/Character$UnicodeScript;
-            return list(
-                chain(
-                    ["package:" + x for x in packages],
-                    ["class:" + x for x in classes],
-                    ["member:" + x for x in member]))
-    #pylint: enable=line-too-long
-
-    def add(self, signature, value):
-        """Associate the value with the specific signature.
-
-        :param signature: the member signature
-        :param value: the value to associated with the signature
-        :return: n/a
-        """
-        # Split the signature into elements.
-        elements = self.signatureToElements(signature)
-        # Find the Node associated with the deepest class.
-        node = self
-        for element in elements[:-1]:
-            if element in node.nodes:
-                node = node.nodes[element]
-            else:
-                next_node = InteriorNode()
-                node.nodes[element] = next_node
-                node = next_node
-        # Add a Leaf containing the value and associate it with the member
-        # signature within the class.
-        lastElement = elements[-1]
-        if not lastElement.startswith("member:"):
-            raise Exception(
-                "Invalid signature: %s, does not identify a specific member" %
-                signature)
-        if lastElement in node.nodes:
-            raise Exception("Duplicate signature: %s" % signature)
-        node.nodes[lastElement] = Leaf(value)
-
-    def getMatchingRows(self, pattern):
-        """Get the values (plural) associated with the pattern.
-
-        e.g. If the pattern is a full signature then this will return a list
-        containing the value associated with that signature.
-
-        If the pattern is a class then this will return a list containing the
-        values associated with all members of that class.
-
-        If the pattern is a package then this will return a list containing the
-        values associated with all the members of all the classes in that
-        package and sub-packages.
-
-        If the pattern ends with "*" then the preceding part is treated as a
-        package and this will return a list containing the values associated
-        with all the members of all the classes in that package.
-
-        If the pattern ends with "**" then the preceding part is treated
-        as a package and this will return a list containing the values
-        associated with all the members of all the classes in that package and
-        all sub-packages.
-
-        :param pattern: the pattern which could be a complete signature or a
-        class, or package wildcard.
-        :return: an iterable containing all the values associated with the
-        pattern.
-        """
-        elements = self.signatureToElements(pattern)
-        node = self
-        # Include all values from this node and all its children.
-        selector = lambda x: True
-        lastElement = elements[-1]
-        if lastElement in ("*", "**"):
-            elements = elements[:-1]
-            if lastElement == "*":
-                # Do not include values from sub-packages.
-                selector = lambda x: not x.startswith("package:")
-        for element in elements:
-            if element in node.nodes:
-                node = node.nodes[element]
-            else:
-                return []
-        return chain.from_iterable(node.values(selector))
-
-    def values(self, selector):
-        """:param selector: a function that can be applied to a key in the nodes
-        attribute to determine whether to return its values.
-
-        :return: A list of iterables of all the values associated with
-        this node and its children.
-        """
-        values = []
-        self.appendValues(values, selector)
-        return values
-
-    def appendValues(self, values, selector):
-        """Append the values associated with this node and its children to the
-        list.
-
-        For each item (key, child) in nodes the child node's values are returned
-        if and only if the selector returns True when called on its key. A child
-        node's values are all the values associated with it and all its
-        descendant nodes.
-
-        :param selector: a function that can be applied to a key in the nodes
-        attribute to determine whether to return its values.
-        :param values: a list of a iterables of values.
-        """
-        for key, node in self.nodes.items():
-            if selector(key):
-                node.appendValues(values, lambda x: True)
-
-
-class Leaf:
-    """A leaf of the trie
-
-    Attributes:
-        value: the value associated with this leaf.
-    """
-
-    def __init__(self, value):
-        self.value = value
-
-    def values(self, selector): #pylint: disable=unused-argument
-        """:return: A list of a list of the value associated with this node.
-        """
-        return [[self.value]]
-
-    def appendValues(self, values, selector): #pylint: disable=unused-argument
-        """Appends a list of the value associated with this node to the list.
-
-        :param values: a list of a iterables of values.
-        """
-        values.append([self.value])
+from signature_trie import signature_trie
 
 
 def dict_reader(csvfile):
@@ -259,7 +34,7 @@
 
 
 def read_flag_trie_from_stream(stream):
-    trie = InteriorNode()
+    trie = signature_trie()
     reader = dict_reader(stream)
     for row in reader:
         signature = row["signature"]
@@ -269,8 +44,7 @@
 
 def extract_subset_from_monolithic_flags_as_dict_from_file(
         monolithicTrie, patternsFile):
-    """Extract a subset of flags from the dict containing all the monolithic
-    flags.
+    """Extract a subset of flags from the dict of monolithic flags.
 
     :param monolithicFlagsDict: the dict containing all the monolithic flags.
     :param patternsFile: a file containing a list of signature patterns that
@@ -284,8 +58,7 @@
 
 def extract_subset_from_monolithic_flags_as_dict_from_stream(
         monolithicTrie, stream):
-    """Extract a subset of flags from the trie containing all the monolithic
-    flags.
+    """Extract a subset of flags from the trie of monolithic flags.
 
     :param monolithicTrie: the trie containing all the monolithic flags.
     :param stream: a stream containing a list of signature patterns that define
@@ -295,7 +68,7 @@
     dict_signature_to_row = {}
     for pattern in stream:
         pattern = pattern.rstrip()
-        rows = monolithicTrie.getMatchingRows(pattern)
+        rows = monolithicTrie.get_matching_rows(pattern)
         for row in rows:
             signature = row["signature"]
             dict_signature_to_row[signature] = row
@@ -303,8 +76,10 @@
 
 
 def read_signature_csv_from_stream_as_dict(stream):
-    """Read the csv contents from the stream into a dict. The first column is
-    assumed to be the signature and used as the key.
+    """Read the csv contents from the stream into a dict.
+
+    The first column is assumed to be the signature and used as the
+    key.
 
     The whole row is stored as the value.
     :param stream: the csv contents to read
@@ -319,8 +94,10 @@
 
 
 def read_signature_csv_from_file_as_dict(csvFile):
-    """Read the csvFile into a dict. The first column is assumed to be the
-    signature and used as the key.
+    """Read the csvFile into a dict.
+
+    The first column is assumed to be the signature and used as the
+    key.
 
     The whole row is stored as the value.
     :param csvFile: the csv file to read
@@ -363,8 +140,7 @@
 def main(argv):
     args_parser = argparse.ArgumentParser(
         description="Verify that sets of hidden API flags are each a subset of "
-        "the monolithic flag file."
-    )
+        "the monolithic flag file.")
     args_parser.add_argument("monolithicFlags", help="The monolithic flag file")
     args_parser.add_argument(
         "modularFlags",