1 files changed, 419 insertions, 0 deletions
diff --git a/src/hydrilla_builder/build.py b/src/hydrilla_builder/build.py
new file mode 100644
index 0000000..e70e360
--- /dev/null
+++ b/src/hydrilla_builder/build.py
@@ -0,0 +1,419 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
+# Building Hydrilla packages.
+#
+# This file is part of Hydrilla
+#
+# Copyright (C) 2021,2022 Wojtek Kosior
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+#
+# I, Wojtek Kosior, thereby promise not to sue for violation of this
+# file's license. Although I request that you do not make use this code
+# in a proprietary program, I am not going to enforce this in court.
+
+
+import json
+import re
+import zipfile
+from pathlib import Path
+from hashlib import sha256
+from sys import stderr
+
+import jsonschema
+
+here = Path(__file__).resolve().parent
+with open(here / 'schemas' / 'package_source-1.schema.json') as schema_file:
+    index_json_schema = json.load(schema_file)
+
+class FileReferenceError(Exception):
+    """
+    Exception used to report various problems concerning files referenced from
+    source package's index.json.
+    """
+
+class ReuseError(Exception):
+    """
+    Exception used to report various problems when calling the REUSE tool.
+    """
+
+strip_comment_re = re.compile(r'''
+^ # match from the beginning of each line
+( # catch the part before '//' comment
+  (?: # this group matches either a string or a single out-of-string character
+    [^"/] |
+    "
+    (?: # this group matches any in-a-string character
+      [^"\\] |          # match any normal character
+      \\[^u] |          # match any escaped character like '\f' or '\n'
+      \\u[a-fA-F0-9]{4} # match an escape
+    )*
+    "
+  )*
+)
+# expect either end-of-line or a comment:
+# * unterminated strings will cause matching to fail
+# * bad comment (with '/' instead of '//') will be indicated by second group
+#   having length 1 instead of 2 or 0
+(//?|$)
+''', re.VERBOSE)
+
+def strip_json_comments(text):
+    """
+    Accept JSON text with optional C++-style ('//') comments and return the text
+    with comments removed. Consecutive slashes inside strings are handled
+    properly. A spurious single slash ('/') shall generate an error. Errors in
+    JSON itself shall be ignored.
+    """
+    processed = 0
+    stripped_text = []
+    for line in text.split('\n'):
+        match = strip_comment_re.match(line)
+
+        if match is None: # unterminated string
+            # ignore this error, let json module report it
+            stripped = line
+        elif len(match[2]) == 1:
+            raise json.JSONDecodeError('bad comment', text,
+                                       processed + len(match[1]))
+        else:
+            stripped = match[1]
+
+        stripped_text.append(stripped)
+        processed += len(line) + 1
+
+    return '\n'.join(stripped_text)
+
+def normalize_version(ver):
+    '''
+    'ver' is an array of integers. Strip right-most zeroes from ver.
+
+    Returns a *new* array. Doesn't modify its argument.
+    '''
+    new_len = 0
+    for i, num in enumerate(ver):
+        if num != 0:
+            new_len = i + 1
+
+    return ver[:new_len]
+
+class FileBuffer:
+    """
+    Implement a file-like object that buffers data written to it.
+    """
+    def __init__(self):
+        """
+        Initialize FileBuffer.
+        """
+        self.chunks = []
+
+    def write(self, b):
+        """
+        Buffer 'b', return number of bytes buffered.
+
+        'b' is expected to be an instance of 'bytes' or 'str', in which case it
+        gets encoded as UTF-8.
+        """
+        if type(b) is str:
+            b = b.encode()
+        self.chunks.append(b)
+        return len(b)
+
+    def flush(self):
+        """
+        A no-op mock of file-like object's flush() method.
+        """
+        pass
+
+    def get_bytes(self):
+        """
+        Return all data written so far concatenated into a single 'bytes'
+        object.
+        """
+        return b''.join(self.chunks)
+
+def generate_spdx_report(root):
+    """
+    Use REUSE tool to generate an SPDX report for sources under 'root' and
+    return the report's contents as 'bytes'.
+
+    'root' shall be an instance of pathlib.Path.
+
+    In case the directory tree under 'root' does not constitute a
+    REUSE-compliant package, linting report is printed to standard output and
+    an exception is raised.
+
+    In case the reuse package is not installed, an exception is also raised.
+    """
+    try:
+        from reuse._main import main as reuse_main
+    except ModuleNotFoundError:
+        ReuseError("Could not import 'reuse'. Is the tool installed and visible to this Python instance?")
+
+    mocked_output = FileBuffer()
+    if reuse_main(args=['--root', str(root), 'lint'], out=mocked_output) != 0:
+        stderr.write(mocked_out.get_bytes())
+        raise ReuseError('Attempt to generate an SPDX report for a REUSE-incompliant package.')
+
+    mocked_output = FileBuffer()
+    if reuse_main(args=['--root', str(root), 'spdx'], out=mocked_output) != 0:
+        stderr.write(mocked_out.get_bytes())
+        raise ReuseError("Couldn't generate an SPDX report for package.")
+
+    return mocked_output.get_bytes()
+
+class FileRef:
+    """Represent reference to a file in the package."""
+    def __init__(self, path: Path, contents: bytes):
+        """Initialize FileRef."""
+        self.include_in_distribution = False
+        self.include_in_zipfile      = True
+        self.path                    = path
+        self.contents                = contents
+
+        self.contents_hash = sha256(contents).digest().hex()
+
+    def make_ref_dict(self, filename: str):
+        """
+        Represent the file reference through a dict that can be included in JSON
+        defintions.
+        """
+        return {
+            'file':   filename,
+            'sha256': self.contents_hash
+        }
+
+class Build:
+    """
+    Build a Hydrilla package.
+    """
+    def __init__(self, srcdir, index_json_path):
+        """
+        Initialize a build. All files to be included in a distribution package
+        are loaded into memory, all data gets validated and all necessary
+        computations (e.g. preparing of hashes) are performed.
+
+        'srcdir' and 'index_json' are expected to be pathlib.Path objects.
+        """
+        self.srcdir          = srcdir.resolve()
+        self.index_json_path = index_json_path
+        self.files_by_path   = {}
+        self.resource_list   = []
+        self.mapping_list    = []
+
+        if not index_json_path.is_absolute():
+            self.index_json_path = (self.srcdir / self.index_json_path)
+
+        self.index_json_path = self.index_json_path.resolve()
+
+        with open(self.index_json_path, 'rt') as index_file:
+            index_json_text = index_file.read()
+
+        index_obj = json.loads(strip_json_comments(index_json_text))
+
+        self.files_by_path[self.index_json_path] = \
+            FileRef(self.index_json_path, index_json_text.encode())
+
+        self._process_index_json(index_obj)
+
+    def _process_file(self, filename: str, include_in_distribution: bool=True):
+        """
+        Resolve 'filename' relative to srcdir, load it to memory (if not loaded
+        before), compute its hash and store its information in
+        'self.files_by_path'.
+
+        'filename' shall represent a relative path using '/' as a separator.
+
+        if 'include_in_distribution' is True it shall cause the file to not only
+        be included in the source package's zipfile, but also written as one of
+        built package's files.
+
+        Return file's reference object that can be included in JSON defintions
+        of various kinds.
+        """
+        path = self.srcdir
+        for segment in filename.split('/'):
+            path /= segment
+
+        path = path.resolve()
+        if not path.is_relative_to(self.srcdir):
+            raise FileReferenceException(f"Attempt to load '{filename}' which lies outside package source directory.")
+
+        if path == self.index_json_path:
+            raise FileReferenceException("Attempt to load 'index.json' which is a reserved filename.")
+
+        file_ref = self.files_by_path.get(path)
+        if file_ref is None:
+            with open(path, 'rb') as file_handle:
+                contents = file_handle.read()
+
+            file_ref = FileRef(path, contents)
+            self.files_by_path[path] = file_ref
+
+        if include_in_distribution:
+            file_ref.include_in_distribution = True
+
+        return file_ref.make_ref_dict(filename)
+
+    def _prepare_source_package_zip(self, root_dir_name: str):
+        """
+        Create and store in memory a .zip archive containing files needed to
+        build this source package.
+
+        'root_dir_name' shall not contain any slashes ('/').
+
+        Return zipfile's sha256 sum's hexstring.
+        """
+        fb = FileBuffer()
+        root_dir_path = Path(root_dir_name)
+
+        def zippath(file_path):
+            return str(root_dir_path / file_path.relative_to(self.srcdir))
+
+        with zipfile.ZipFile(fb, 'w') as xpi:
+            for file_ref in self.files_by_path.values():
+                if file_ref.include_in_zipfile:
+                    xpi.writestr(zippath(file_ref.path), file_ref.contents)
+
+        self.source_zip_contents = fb.get_bytes()
+
+        return sha256(self.source_zip_contents).digest().hex()
+
+    def _process_item(self, item_def: dict):
+        """
+        Process 'item_def' as definition of a resource/mapping and store in
+        memory its processed form and files used by it.
+        """
+        copy_props = ['type', 'identifier', 'long_name', 'uuid', 'description']
+        if 'comment' in item_def:
+            copy_props.append(copy_props)
+
+        if item_def['type'] == 'resource':
+            item_list = self.resource_list
+
+            copy_props.append('revision')
+
+            script_file_refs = [self._process_file(f['file'])
+                                for f in item_def.get('scripts', [])]
+
+            new_item_obj = {
+                'dependencies': item_def.get('dependencies', []),
+                'scripts':      script_file_refs
+            }
+        else:
+            item_list = self.mapping_list
+
+            payloads = dict([(pat, {'identifier': res_ref['identifier']})
+                             for pat, res_ref in item_def['payloads'].items()])
+
+            new_item_obj = {
+                'payloads': payloads
+            }
+
+        new_item_obj.update([(p, item_def[p]) for p in copy_props])
+
+        new_item_obj['version'] = normalize_version(item_def['version'])
+        new_item_obj['api_schema_version'] = [1, 0, 1]
+
+        item_list.append(new_item_obj)
+
+    def _process_index_json(self, index_obj: dict):
+        """
+        Process 'index_obj' as contents of source package's index.json and store
+        in memory this source package's zipfile as well as package's individual
+        files and computed definitions of the source package and items defined
+        in it.
+        """
+        jsonschema.validate(index_obj, index_json_schema)
+
+        generate_spdx = index_obj.get('reuse_generate_spdx_report', False)
+        if generate_spdx:
+            contents  = generate_spdx_report(self.srcdir)
+            spdx_path = (self.srcdir / 'report.spdx').resolve()
+            spdx_ref  = FileRef(spdx_path, contents)
+
+            spdx_ref.include_in_zipfile = False
+            self.files_by_path[spdx_path] = spdx_ref
+
+        copyright_file_refs = \
+            [self._process_file(f['file']) for f in index_obj['copyright']]
+
+        if generate_spdx and not spdx_ref.include_in_distribution:
+            raise FileReferenceError("Told to generate 'report.spdx' but 'report.spdx' is not listed among copyright files. Refusing to proceed.")
+
+        item_refs = [self._process_item(d) for d in index_obj['definitions']]
+
+        for file_ref in index_obj.get('additional_files', []):
+            self._process_file(file_ref['file'], include_in_distribution=False)
+
+        root_dir_path = Path(index_obj['source_name'])
+
+        source_archives_obj = {
+            'zip' : {
+                'sha256': self._prepare_source_package_zip(root_dir_path)
+            }
+        }
+
+        self.source_description = {
+            'api_schema_version': [1, 0, 1],
+            'source_name':        index_obj['source_name'],
+            'source_copyright':   copyright_file_refs,
+            'upstream_url':       index_obj['upstream_url'],
+            'definitions':        item_refs,
+            'source_archives':    source_archives_obj
+        }
+
+    def write_source_package_zip(self, dstpath: Path):
+        """
+        Create a .zip archive containing files needed to build this source
+        package and write it at 'dstpath'.
+        """
+        with open(dstpath, 'wb') as output:
+            output.write(self.source_zip_contents)
+
+    def write_package_files(self, dstpath: Path):
+        """Write package files under 'dstpath' for distribution."""
+        file_dir_path = (dstpath / 'file').resolve()
+        file_dir_path.mkdir(parents=True, exist_ok=True)
+
+        for file_ref in self.files_by_path.values():
+            if file_ref.include_in_distribution:
+                file_name = f'sha256-{file_ref.contents_hash}'
+                with open(file_dir_path / file_name, 'wb') as output:
+                    output.write(file_ref.contents)
+
+        source_dir_path = (dstpath / 'source').resolve()
+        source_dir_path.mkdir(parents=True, exist_ok=True)
+        source_name = self.source_description["source_name"]
+
+        with open(source_dir_path / f'{source_name}.json', 'wt') as output:
+            json.dump(self.source_description, output)
+
+        with open(source_dir_path / f'{source_name}.zip', 'wb') as output:
+            output.write(self.source_zip_contents)
+
+        for item_type, item_list in [
+                ('resource', self.resource_list),
+                ('mapping', self.mapping_list)
+        ]:
+            item_type_dir_path = (dstpath / item_type).resolve()
+
+            for item_def in item_list:
+                item_dir_path = item_type_dir_path / item_def['identifier']
+                item_dir_path.mkdir(parents=True, exist_ok=True)
+
+                version = '.'.join([str(n) for n in item_def['version']])
+                with open(item_dir_path / version, 'wt') as output:
+                    json.dump(item_def, output)