commands/show: Adds show command

The show command will try to use pandoc and man to display the relevant
information and will fall back to printing the markdown if pandoc is not
available.

wa/commands/show.py

@@ -0,0 +1,94 @@
+#    Copyright 2014-2015 ARM Limited
+#
+# 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.
+#
+from subprocess import call, Popen, PIPE
+
+from wa import Command
+from wa.framework import pluginloader
+from wa.framework.exception import NotFoundError
+from wa.framework.target.descriptor import get_target_descriptions
+from wa.utils.doc import (strip_inlined_text, get_rst_from_plugin,
+                          get_params_rst, underline)
+from wa.utils.misc import which
+
+from devlib.utils.misc import escape_double_quotes
+
+class ShowCommand(Command):
+
+    name = 'show'
+    description = 'Display documentation for the specified plugin (workload, instrument, etc.).'
+
+    def initialize(self, context):
+        self.parser.add_argument('plugin', metavar='PLUGIN',
+                                 help='The name of the plugin to display documentation for.')
+
+    def execute(self, state, args):
+        name = args.plugin
+        rst_output = None
+
+        plugin = get_plugin(name)
+        if plugin:
+            rst_output = get_rst_from_plugin(plugin)
+        else:
+            target = get_target_description(name)
+            if target:
+                rst_output = get_rst_from_target(target)
+
+        if not rst_output:
+            raise NotFoundError('Could not find plugin or alias "{}"'.format(name))
+
+        if which('pandoc'):
+            p = Popen(['pandoc', '-f', 'rst', '-t', 'man'], stdin=PIPE, stdout=PIPE, stderr=PIPE)
+            output, _ = p.communicate(rst_output)
+            # Make sure to double escape back slashes
+            output = output.replace('\\', '\\\\\\')
+            # Correctly format the tile of the man page
+            output = output.replace('.SH', '.TH', 1)
+            call('echo "{}" | man -l -'.format(escape_double_quotes(output)), shell=True)
+        else:
+            print rst_output
+
+
+def get_plugin(name):
+    for plugin in pluginloader.list_plugins():
+        if name == plugin.name:
+            return plugin
+        if hasattr(plugin, 'alias'):
+            for alias in plugin.alias:
+                if name == alias:
+                    return plugin
+
+
+def get_target_description(name):
+    targets = get_target_descriptions()
+    for target in targets:
+        if name == target.name:
+            return target
+
+
+def get_rst_from_target(target):
+    text = underline(target.name, '-')
+    if hasattr(target, 'description'):
+        desc = strip_inlined_text(target.description or '')
+        text += desc
+    conn_params_rst = get_params_rst(target.conn_params)
+    if conn_params_rst:
+        text += underline('\nconnection parameters', '~') + conn_params_rst
+    platform_params_rst = get_params_rst(target.platform_params)
+    if platform_params_rst:
+        text += underline('\nplatform parameters', '~') + platform_params_rst
+    target_params_rst = get_params_rst(target.target_params)
+    if target_params_rst:
+        text += underline('\nconnection parameters', '~') + target_params_rst
+    return text + '\n'