qapi: Add a primitive to include other files from a QAPI schema file

The primitive uses JSON syntax, and include paths are relative to the file using the directive:

  { 'include': 'path/to/file.json' }

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

docs/qapi-code-gen.txt

@@ -40,6 +40,17 @@ enumeration types and union types.
 Generally speaking, types definitions should always use CamelCase for the type
 names. Command names should be all lower case with words separated by a hyphen.
 
+
+=== Includes ===
+
+The QAPI schema definitions can be modularized using the 'include' directive:
+
+ { 'include': 'path/to/file.json'}
+
+The directive is evaluated recursively, and include paths are relative to the
+file using the directive.
+
+
 === Complex types ===
 
 A complex type is a dictionary containing a single key whose value is a

scripts/qapi.py

@@ -11,6 +11,7 @@
 # This work is licensed under the terms of the GNU GPL, version 2.
 # See the COPYING file in the top-level directory.
 
+import re
 from ordereddict import OrderedDict
 import os
 import sys
@@ -36,9 +37,17 @@
     'uint64':   'QTYPE_QINT',
 }
 
+def error_path(parent):
+    res = ""
+    while parent:
+        res = ("In file included from %s:%d:\n" % (parent['file'],
+                                                   parent['line'])) + res
+        parent = parent['parent']
+    return res
+
 class QAPISchemaError(Exception):
     def __init__(self, schema, msg):
-        self.fp = schema.fp
+        self.input_file = schema.input_file
         self.msg = msg
         self.col = 1
         self.line = schema.line
@@ -47,23 +56,31 @@ def __init__(self, schema, msg):
                 self.col = (self.col + 7) % 8 + 1
             else:
                 self.col += 1
+        self.info = schema.parent_info
 
     def __str__(self):
-        return "%s:%s:%s: %s" % (self.fp.name, self.line, self.col, self.msg)
+        return error_path(self.info) + \
+            "%s:%d:%d: %s" % (self.input_file, self.line, self.col, self.msg)
 
 class QAPIExprError(Exception):
     def __init__(self, expr_info, msg):
-        self.fp = expr_info['fp']
-        self.line = expr_info['line']
+        self.info = expr_info
         self.msg = msg
 
     def __str__(self):
-        return "%s:%s: %s" % (self.fp.name, self.line, self.msg)
+        return error_path(self.info['parent']) + \
+            "%s:%d: %s" % (self.info['file'], self.info['line'], self.msg)
 
 class QAPISchema:
 
-    def __init__(self, fp):
-        self.fp = fp
+    def __init__(self, fp, input_relname=None, include_hist=[], parent_info=None):
+        input_fname = os.path.abspath(fp.name)
+        if input_relname is None:
+            input_relname = fp.name
+        self.input_dir = os.path.dirname(input_fname)
+        self.input_file = input_relname
+        self.include_hist = include_hist + [(input_relname, input_fname)]
+        self.parent_info = parent_info
         self.src = fp.read()
         if self.src == '' or self.src[-1] != '\n':
             self.src += '\n'
@@ -74,10 +91,33 @@ def __init__(self, fp):
         self.accept()
 
         while self.tok != None:
-            expr_info = {'fp': fp, 'line': self.line}
-            expr_elem = {'expr': self.get_expr(False),
-                         'info': expr_info}
-            self.exprs.append(expr_elem)
+            expr_info = {'file': input_relname, 'line': self.line, 'parent': self.parent_info}
+            expr = self.get_expr(False)
+            if isinstance(expr, dict) and "include" in expr:
+                if len(expr) != 1:
+                    raise QAPIExprError(expr_info, "Invalid 'include' directive")
+                include = expr["include"]
+                if not isinstance(include, str):
+                    raise QAPIExprError(expr_info,
+                                        'Expected a file name (string), got: %s'
+                                        % include)
+                include_path = os.path.join(self.input_dir, include)
+                if any(include_path == elem[1]
+                       for elem in self.include_hist):
+                    raise QAPIExprError(expr_info, "Inclusion loop for %s"
+                                        % include)
+                try:
+                    fobj = open(include_path, 'r')
+                except IOError as e:
+                    raise QAPIExprError(expr_info,
+                                        '%s: %s' % (e.strerror, include))
+                exprs_include = QAPISchema(fobj, include,
+                                           self.include_hist, expr_info)
+                self.exprs.extend(exprs_include.exprs)
+            else:
+                expr_elem = {'expr': expr,
+                             'info': expr_info}
+                self.exprs.append(expr_elem)
 
     def accept(self):
         while True:
@@ -267,7 +307,7 @@ def check_exprs(schema):
 def parse_schema(input_file):
     try:
         schema = QAPISchema(open(input_file, "r"))
-    except QAPISchemaError, e:
+    except (QAPISchemaError, QAPIExprError), e:
         print >>sys.stderr, e
         exit(1)
 

tests/Makefile

@@ -190,7 +190,10 @@ check-qapi-schema-y := $(addprefix tests/qapi-schema/, \
         duplicate-key.json union-invalid-base.json flat-union-no-base.json \
         flat-union-invalid-discriminator.json \
         flat-union-invalid-branch-key.json flat-union-reverse-define.json \
-        flat-union-string-discriminator.json)
+        flat-union-string-discriminator.json \
+        include-simple.json include-relpath.json include-format-err.json \
+        include-non-file.json include-no-file.json include-before-err.json \
+        include-nested-err.json include-self-cycle.json include-cycle.json)
 
 GENERATED_HEADERS += tests/test-qapi-types.h tests/test-qapi-visit.h tests/test-qmp-commands.h
 

tests/qapi-schema/include-before-err.err

@@ -0,0 +1 @@
+tests/qapi-schema/include-before-err.json:2:13: Expected ":"

tests/qapi-schema/include-before-err.exit

@@ -0,0 +1 @@
+1

tests/qapi-schema/include-before-err.json

@@ -0,0 +1,2 @@
+{ 'include': 'include-simple-sub.json' }
+{ 'command' 'missing-colon' }

tests/qapi-schema/include-cycle-b.json

@@ -0,0 +1 @@
+{ 'include': 'include-cycle-c.json' }

tests/qapi-schema/include-cycle-c.json

@@ -0,0 +1 @@
+{ 'include': 'include-cycle.json' }

tests/qapi-schema/include-cycle.err

@@ -0,0 +1,3 @@
+In file included from tests/qapi-schema/include-cycle.json:1:
+In file included from include-cycle-b.json:1:
+include-cycle-c.json:1: Inclusion loop for include-cycle.json

tests/qapi-schema/include-cycle.exit

@@ -0,0 +1 @@
+1

tests/qapi-schema/include-cycle.json

@@ -0,0 +1 @@
+{ 'include': 'include-cycle-b.json' }

tests/qapi-schema/include-format-err.err

@@ -0,0 +1 @@
+tests/qapi-schema/include-format-err.json:1: Invalid 'include' directive

tests/qapi-schema/include-format-err.exit

@@ -0,0 +1 @@
+1

tests/qapi-schema/include-format-err.json

@@ -0,0 +1,2 @@
+{ 'include': 'include-simple-sub.json',
+  'foo': 'bar' }

tests/qapi-schema/include-nested-err.err

@@ -0,0 +1,2 @@
+In file included from tests/qapi-schema/include-nested-err.json:1:
+missing-colon.json:1:10: Expected ":"

tests/qapi-schema/include-nested-err.exit

@@ -0,0 +1 @@
+1

tests/qapi-schema/include-nested-err.json

@@ -0,0 +1 @@
+{ 'include': 'missing-colon.json' }

tests/qapi-schema/include-no-file.err

@@ -0,0 +1 @@
+tests/qapi-schema/include-no-file.json:1: No such file or directory: include-no-file-sub.json

tests/qapi-schema/include-no-file.exit

@@ -0,0 +1 @@
+1

tests/qapi-schema/include-no-file.json

@@ -0,0 +1 @@
+{ 'include': 'include-no-file-sub.json' }

tests/qapi-schema/include-non-file.err

@@ -0,0 +1 @@
+tests/qapi-schema/include-non-file.json:1: Expected a file name (string), got: ['foo', 'bar']

tests/qapi-schema/include-non-file.exit

@@ -0,0 +1 @@
+1

tests/qapi-schema/include-non-file.json

@@ -0,0 +1 @@
+{ 'include': [ 'foo', 'bar' ] }

tests/qapi-schema/include-relpath-sub.json

@@ -0,0 +1,2 @@
+{ 'enum': 'Status',
+  'data': [ 'good', 'bad', 'ugly' ] }

tests/qapi-schema/include-relpath.exit

@@ -0,0 +1 @@
+0

tests/qapi-schema/include-relpath.json

@@ -0,0 +1 @@
+{ 'include': 'include/relpath.json' }

tests/qapi-schema/include-relpath.out

@@ -0,0 +1,3 @@
+[OrderedDict([('enum', 'Status'), ('data', ['good', 'bad', 'ugly'])])]
+[{'enum_name': 'Status', 'enum_values': ['good', 'bad', 'ugly']}]
+[]

tests/qapi-schema/include-self-cycle.err

@@ -0,0 +1 @@
+tests/qapi-schema/include-self-cycle.json:1: Inclusion loop for include-self-cycle.json

tests/qapi-schema/include-self-cycle.exit

@@ -0,0 +1 @@
+1

tests/qapi-schema/include-self-cycle.json

@@ -0,0 +1 @@
+{ 'include': 'include-self-cycle.json' }

tests/qapi-schema/include-simple-sub.json

@@ -0,0 +1,2 @@
+{ 'enum': 'Status',
+  'data': [ 'good', 'bad', 'ugly' ] }

tests/qapi-schema/include-simple.exit

@@ -0,0 +1 @@
+0

tests/qapi-schema/include-simple.json

@@ -0,0 +1 @@
+{ 'include': 'include-simple-sub.json' }

tests/qapi-schema/include-simple.out

@@ -0,0 +1,3 @@
+[OrderedDict([('enum', 'Status'), ('data', ['good', 'bad', 'ugly'])])]
+[{'enum_name': 'Status', 'enum_values': ['good', 'bad', 'ugly']}]
+[]

tests/qapi-schema/include/relpath.json

@@ -0,0 +1 @@
+{ 'include': '../include-relpath-sub.json' }