Get NDK python script tests running.

Imports weren't working in tests because the package had been created.
The Python "binaries" built by Soong don't seem to take their own
pkg_path into account, so I split the separate pieces of code here out
into their own packages.

Note that the ndk_api_coverage_parser tests do not actually pass
before or after this change (seems like it might be a
non-deterministic ordering issue in the attributes of the generated
output?), but they can at least be run now.

Test: pytest ndkstubgen
Test: pytest symbolfile
Test: pytest ndk_api_coverage_parser
Test: out/host/linux-x86/nativetest64/test_ndkstubgen/test_ndkstubgen
Test: out/host/linux-x86/nativetest64/test_symbolfile/test_symbolfile
Test: out/host/linux-x86/nativetest64/test_ndk_api_coverage_parser/test_ndk_api_coverage_parser
Bug: None
Change-Id: I2ac22f7ced7566e4808070f2f72fd04355846e0b
diff --git a/cc/ndkstubgen/__init__.py b/cc/ndkstubgen/__init__.py
new file mode 100755
index 0000000..2f4326a
--- /dev/null
+++ b/cc/ndkstubgen/__init__.py
@@ -0,0 +1,149 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2016 The Android Open Source Project
+#
+# 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.
+#
+"""Generates source for stub shared libraries for the NDK."""
+import argparse
+import json
+import logging
+import os
+import sys
+
+import symbolfile
+
+
+class Generator:
+    """Output generator that writes stub source files and version scripts."""
+    def __init__(self, src_file, version_script, arch, api, llndk, apex):
+        self.src_file = src_file
+        self.version_script = version_script
+        self.arch = arch
+        self.api = api
+        self.llndk = llndk
+        self.apex = apex
+
+    def write(self, versions):
+        """Writes all symbol data to the output files."""
+        for version in versions:
+            self.write_version(version)
+
+    def write_version(self, version):
+        """Writes a single version block's data to the output files."""
+        if symbolfile.should_omit_version(version, self.arch, self.api,
+                                          self.llndk, self.apex):
+            return
+
+        section_versioned = symbolfile.symbol_versioned_in_api(
+            version.tags, self.api)
+        version_empty = True
+        pruned_symbols = []
+        for symbol in version.symbols:
+            if symbolfile.should_omit_symbol(symbol, self.arch, self.api,
+                                             self.llndk, self.apex):
+                continue
+
+            if symbolfile.symbol_versioned_in_api(symbol.tags, self.api):
+                version_empty = False
+            pruned_symbols.append(symbol)
+
+        if len(pruned_symbols) > 0:
+            if not version_empty and section_versioned:
+                self.version_script.write(version.name + ' {\n')
+                self.version_script.write('    global:\n')
+            for symbol in pruned_symbols:
+                emit_version = symbolfile.symbol_versioned_in_api(
+                    symbol.tags, self.api)
+                if section_versioned and emit_version:
+                    self.version_script.write('        ' + symbol.name + ';\n')
+
+                weak = ''
+                if 'weak' in symbol.tags:
+                    weak = '__attribute__((weak)) '
+
+                if 'var' in symbol.tags:
+                    self.src_file.write('{}int {} = 0;\n'.format(
+                        weak, symbol.name))
+                else:
+                    self.src_file.write('{}void {}() {{}}\n'.format(
+                        weak, symbol.name))
+
+            if not version_empty and section_versioned:
+                base = '' if version.base is None else ' ' + version.base
+                self.version_script.write('}' + base + ';\n')
+
+
+def parse_args():
+    """Parses and returns command line arguments."""
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument('-v', '--verbose', action='count', default=0)
+
+    parser.add_argument(
+        '--api', required=True, help='API level being targeted.')
+    parser.add_argument(
+        '--arch', choices=symbolfile.ALL_ARCHITECTURES, required=True,
+        help='Architecture being targeted.')
+    parser.add_argument(
+        '--llndk', action='store_true', help='Use the LLNDK variant.')
+    parser.add_argument(
+        '--apex', action='store_true', help='Use the APEX variant.')
+
+    parser.add_argument(
+        '--api-map', type=os.path.realpath, required=True,
+        help='Path to the API level map JSON file.')
+
+    parser.add_argument(
+        'symbol_file', type=os.path.realpath, help='Path to symbol file.')
+    parser.add_argument(
+        'stub_src', type=os.path.realpath,
+        help='Path to output stub source file.')
+    parser.add_argument(
+        'version_script', type=os.path.realpath,
+        help='Path to output version script.')
+
+    return parser.parse_args()
+
+
+def main():
+    """Program entry point."""
+    args = parse_args()
+
+    with open(args.api_map) as map_file:
+        api_map = json.load(map_file)
+    api = symbolfile.decode_api_level(args.api, api_map)
+
+    verbose_map = (logging.WARNING, logging.INFO, logging.DEBUG)
+    verbosity = args.verbose
+    if verbosity > 2:
+        verbosity = 2
+    logging.basicConfig(level=verbose_map[verbosity])
+
+    with open(args.symbol_file) as symbol_file:
+        try:
+            versions = symbolfile.SymbolFileParser(symbol_file, api_map,
+                                                   args.arch, api, args.llndk,
+                                                   args.apex).parse()
+        except symbolfile.MultiplyDefinedSymbolError as ex:
+            sys.exit('{}: error: {}'.format(args.symbol_file, ex))
+
+    with open(args.stub_src, 'w') as src_file:
+        with open(args.version_script, 'w') as version_file:
+            generator = Generator(src_file, version_file, args.arch, api,
+                                  args.llndk, args.apex)
+            generator.write(versions)
+
+
+if __name__ == '__main__':
+    main()