Merge branch 'release/1.8'1.8

3 files changed, 64 insertions, 15 deletions

diff --git a/docs/extending.rst b/docs/extending.rst
index 010c810..dc42cb8 100644
--- a/docs/extending.rst
+++ b/docs/extending.rst
@@ -75,7 +75,7 @@ The `RuleGenerator` allows you to extract the documentation rules into an extern
         generator = RuleGenerator(search_path=here/'templates', destination=output)
         generator.process_rules(here/'docs.yaml', system)
 
-The rules document is divided into several targets. Each target can have an own destination. A target is typical for exampe and app, client, server. Each target can have rules for the different symbols (system, module, interface, struct, enum). An each rule finally consists of a destination modifier, additional context and a documents collection.
+The rules document is divided into several targets. Each target can have an own destination. A target is typical for example and app, client, server. Each target can have rules for the different symbols (system, module, interface, struct, enum). An each rule finally consists of a destination modifier, additional context and a documents collection.
 
 .. code-block:: python
 
@@ -123,3 +123,37 @@ Here is an example (``docs.yaml``)
 
 The rule generator adds the ``dst``, ``project`` as also the corresponding symbols to the context automatically. On each level you are able to change the destination or update the context.
 
+
+.. rubric:: Features
+
+The rules document allows to conditional write files based on a feature set. The feature set must be a set of tags indicating the features which will then be checked in the ``when`` section of a rule.
+
+The features are passed to the generator in your custom generator code. The existence of a feature tells the rules engine to check if a ``when`` section exists conditionally execute this rule.
+
+.. code-block:: yaml
+
+    plugin:
+        when: plugin_enabled
+        destination: '{{dst}}/plugin'
+        module:
+            ...
+
+Here the plugin rule will only be run when the feature set contains a 'plugin_enabled' string.
+
+.. rubric:: Preserve
+
+Documents can be marked as preserved to prevent them to be overwritten when the user has edited them. the rules documents has an own marker for this called ``preserve``. This is a list of target documents which shall be be marked preserved by the generator.
+
+
+.. code-block:: yaml
+
+    plugin:
+        interface:
+            documents:
+                '{{interface|lower}}.h': 'plugin/interface.h'
+                '{{interface|lower}}.cpp': 'plugin/interface.cpp'
+            preserve:
+                - '{{interface|lower}}.h'
+                - '{{interface|lower}}.cpp'
+
+In the example above the two interface documents will not be overwritten during a second generator call and can be edited by the user.
diff --git a/qface/__about__.py b/qface/__about__.py
index 4fbd624..c16b3dd 100644
--- a/qface/__about__.py
+++ b/qface/__about__.py
@@ -9,7 +9,7 @@ except NameError:
 __title__ = "qface"
 __summary__ = "A generator framework based on a common modern IDL"
 __url__ = "https://pelagicore.github.io/qface/"
-__version__ = "1.7"
+__version__ = "1.8"
 __author__ = "JRyannel"
 __author_email__ = "qface-generator@googlegroups.com"
 __copyright__ = "2017 Pelagicore"
diff --git a/qface/generator.py b/qface/generator.py
index 572cedf..ef02062 100644
--- a/qface/generator.py
+++ b/qface/generator.py
@@ -137,9 +137,9 @@ class Generator(object):
         data = self.render(template, context)
         if self._has_different_content(data, path):
             if path.exists() and preserve:
-                click.secho('preserve changed file: {0}'.format(path), fg='blue')
+                click.secho('preserve: {0}'.format(path), fg='blue')
             else:
-                click.secho('write changed file: {0}'.format(path), fg='blue')
+                click.secho('create: {0}'.format(path), fg='blue')
                 path.open('w', encoding='utf-8').write(data)
 
     def _has_different_content(self, data, path):
@@ -156,24 +156,28 @@ class Generator(object):
 
 class RuleGenerator(Generator):
     """Generates documents based on a rule YAML document"""
-    def __init__(self, search_path: str, destination: Path, context: dict= {}):
+    def __init__(self, search_path: str, destination:Path, context:dict={}, features:set=set()):
         super().__init__(search_path, context)
         self.context.update({
             'dst': destination,
             'project': Path(destination).name,
         })
         self.destination = '{{dst}}'
+        self.features = features
 
-    def process_rules(self, document: Path, system: System):
+    def process_rules(self, path: Path, system: System, features:set=set()):
         """writes the templates read from the rules document"""
+        self.features.update(features)
         self.context.update({'system': system})
-        rules = FileSystem.load_yaml(document, required=True)
-        for name, target in rules.items():
-            click.secho('process target: {0}'.format(name), fg='green')
-            self._process_target(target, system)
+        document = FileSystem.load_yaml(path, required=True)
+        for module, rules in document.items():
+            click.secho('module: {0}'.format(module), fg='green')
+            self._process_rules(rules, system)
 
-    def _process_target(self, rules: dict, system: System):
+    def _process_rules(self, rules: dict, system: System):
         """ process a set of rules for a target """
+        if not self._shall_proceed(rules):
+            return
         self.context.update(rules.get('context', {}))
         self.destination = rules.get('destination', '{{dst}}')
         self._process_rule(rules.get('system', None), {'system': system})
@@ -188,13 +192,24 @@ class RuleGenerator(Generator):
 
     def _process_rule(self, rule: dict, context: dict):
         """ process a single rule """
-        if not rule:
+        if not rule or not self._shall_proceed(rule):
             return
         self.context.update(context)
         self.context.update(rule.get('context', {}))
         self.destination = rule.get('destination', None)
+        preserved = rule.get('preserve', [])
         for target, source in rule.get('documents', {}).items():
-            self.write(target, source)
+            preserve = target in preserved
+            self.write(target, source, preserve=preserve)
+
+    def _shall_proceed(self, obj):
+        conditions = obj.get('when', [])
+        if not conditions:
+            return True
+        if not isinstance(conditions, list):
+            conditions = [conditions]
+        result = self.features.intersection(set(conditions))
+        return bool(len(result))
 
 
 class FileSystem(object):
@@ -249,7 +264,7 @@ class FileSystem(object):
         updates the tag information of that symbol
         """
         meta = FileSystem.load_yaml(document)
-        click.secho('merge tags from {0}'.format(document), fg='blue')
+        click.secho('merge: {0}'.format(document.name), fg='blue')
         for identifier, data in meta.items():
             symbol = system.lookup(identifier)
             if symbol:
@@ -300,5 +315,5 @@ class FileSystem(object):
         try:
             return yaml.load(document.text(), Loader=Loader)
         except yaml.YAMLError as exc:
-            click.secho(exc, fg='red')
+            click.secho(str(exc), fg='red')
         return {}