ldgen: refactor generation internals

tools/ldgen/linker_script.py

@@ -0,0 +1,95 @@
+#
+# Copyright 2018-2019 Espressif Systems (Shanghai) PTE LTD
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+#
+
+import collections
+import os
+
+from fragments import Fragment
+from generation import GenerationException
+from pyparsing import ParseException, Suppress, White
+
+
+class LinkerScript:
+    """
+    Encapsulates a linker script template file. Finds marker syntax and handles replacement to generate the
+    final output.
+    """
+
+    Marker = collections.namedtuple('Marker', 'target indent rules')
+
+    def __init__(self, template_file):
+        self.members = []
+        self.file = os.path.realpath(template_file.name)
+
+        self._generate_members(template_file)
+
+    def _generate_members(self, template_file):
+        lines = template_file.readlines()
+
+        target = Fragment.IDENTIFIER
+        reference = Suppress('mapping') + Suppress('[') + target.setResultsName('target') + Suppress(']')
+        pattern = White(' \t').setResultsName('indent') + reference
+
+        # Find the markers in the template file line by line. If line does not match marker grammar,
+        # set it as a literal to be copied as is to the output file.
+        for line in lines:
+            try:
+                parsed = pattern.parseString(line)
+
+                indent = parsed.indent
+                target = parsed.target
+
+                marker = LinkerScript.Marker(target, indent, [])
+
+                self.members.append(marker)
+            except ParseException:
+                # Does not match marker syntax
+                self.members.append(line)
+
+    def fill(self, mapping_rules):
+        for member in self.members:
+            target = None
+            try:
+                target = member.target
+                rules = member.rules
+
+                del rules[:]
+
+                rules.extend(mapping_rules[target])
+            except KeyError:
+                message = GenerationException.UNDEFINED_REFERENCE + " to target '" + target + "'."
+                raise GenerationException(message)
+            except AttributeError:
+                pass
+
+    def write(self, output_file):
+        # Add information that this is a generated file.
+        output_file.write('/* Automatically generated file; DO NOT EDIT */\n')
+        output_file.write('/* Espressif IoT Development Framework Linker Script */\n')
+        output_file.write('/* Generated from: %s */\n' % self.file)
+        output_file.write('\n')
+
+        # Do the text replacement
+        for member in self.members:
+            try:
+                indent = member.indent
+                rules = member.rules
+
+                for rule in rules:
+                    generated_line = ''.join([indent, str(rule), '\n'])
+                    output_file.write(generated_line)
+            except AttributeError:
+                output_file.write(member)