Load and store reports

PFERD/crawl/crawler.py

@@ -11,7 +11,7 @@ from ..config import Config, Section
 from ..limiter import Limiter
 from ..logging import ProgressBar, log
 from ..output_dir import FileSink, FileSinkToken, OnConflict, OutputDirectory, OutputDirError, Redownload
-from ..report import MarkConflictError, MarkDuplicateError
+from ..report import MarkConflictError, MarkDuplicateError, Report
 from ..transformer import Transformer
 from ..utils import ReusableAsyncContextManager, fmt_path
 
@@ -229,6 +229,14 @@ class Crawler(ABC):
             section.on_conflict(),
         )
 
+    @property
+    def report(self) -> Report:
+        return self._output_dir.report
+
+    @property
+    def prev_report(self) -> Optional[Report]:
+        return self._output_dir.prev_report
+
     @staticmethod
     async def gather(awaitables: Sequence[Awaitable[Any]]) -> List[Any]:
         """
@@ -298,8 +306,10 @@ class Crawler(ABC):
 
         with log.show_progress():
             self._output_dir.prepare()
+            self._output_dir.load_prev_report()
             await self._run()
             await self._cleanup()
+            self._output_dir.store_report()
 
     @abstractmethod
     async def _run(self) -> None:

PFERD/output_dir.py

@@ -1,4 +1,5 @@
 import filecmp
+import json
 import os
 import random
 import shutil
@@ -13,7 +14,7 @@ from typing import BinaryIO, Iterator, Optional, Tuple
 from rich.markup import escape
 
 from .logging import log
-from .report import Report
+from .report import Report, ReportLoadError
 from .utils import ReusableAsyncContextManager, fmt_path, fmt_real_path, prompt_yes_no
 
 SUFFIX_CHARS = string.ascii_lowercase + string.digits
@@ -134,6 +135,8 @@ class FileSinkToken(ReusableAsyncContextManager[FileSink]):
 
 
 class OutputDirectory:
+    REPORT_FILE = PurePath(".report")
+
     def __init__(
             self,
             root: Path,
@@ -144,7 +147,19 @@ class OutputDirectory:
         self._redownload = redownload
         self._on_conflict = on_conflict
 
+        self._report_path = self.resolve(self.REPORT_FILE)
         self._report = Report()
+        self._prev_report: Optional[Report] = None
+
+        self.register_reserved(self.REPORT_FILE)
+
+    @property
+    def report(self) -> Report:
+        return self._report
+
+    @property
+    def prev_report(self) -> Optional[Report]:
+        return self._prev_report
 
     def prepare(self) -> None:
         log.explain_topic(f"Creating base directory at {fmt_real_path(self._root)}")
@@ -452,3 +467,21 @@ class OutputDirectory:
                 self._report.delete_file(pure)
             except OSError:
                 pass
+
+    def load_prev_report(self) -> None:
+        log.explain_topic(f"Loading previous report from {fmt_real_path(self._report_path)}")
+        try:
+            self._prev_report = Report.load(self._report_path)
+            log.explain("Loaded report successfully")
+        except (OSError, json.JSONDecodeError, ReportLoadError) as e:
+            log.explain("Failed to load report")
+            log.explain(str(e))
+
+    def store_report(self) -> None:
+        log.explain_topic(f"Storing report to {fmt_real_path(self._report_path)}")
+        try:
+            self._report.store(self._report_path)
+            log.explain("Stored report successfully")
+        except OSError as e:
+            log.warn(f"Failed to save report to {fmt_real_path(self._report_path)}")
+            log.warn_contd(str(e))

PFERD/report.py

@@ -1,5 +1,10 @@
-from pathlib import PurePath
-from typing import Set
+import json
+from pathlib import Path, PurePath
+from typing import Any, Dict, List, Set
+
+
+class ReportLoadError(Exception):
+    pass
 
 
 class MarkDuplicateError(Exception):
@@ -48,10 +53,66 @@ class Report:
         self.reserved_files: Set[PurePath] = set()
         self.known_files: Set[PurePath] = set()
 
-        self.new_files: Set[PurePath] = set()
+        self.added_files: Set[PurePath] = set()
         self.changed_files: Set[PurePath] = set()
         self.deleted_files: Set[PurePath] = set()
 
+    @staticmethod
+    def _get_list_of_strs(data: Dict[str, Any], key: str) -> List[str]:
+        result: Any = data.get(key, [])
+
+        if not isinstance(result, list):
+            raise ReportLoadError(f"Incorrect format: {key!r} is not a list")
+
+        for elem in result:
+            if not isinstance(elem, str):
+                raise ReportLoadError(f"Incorrect format: {key!r} must contain only strings")
+
+        return result
+
+    @classmethod
+    def load(cls, path: Path) -> "Report":
+        """
+        May raise OSError, JsonDecodeError, ReportLoadError.
+        """
+
+        with open(path) as f:
+            data = json.load(f)
+
+        if not isinstance(data, dict):
+            raise ReportLoadError("Incorrect format: Root is not an object")
+
+        self = cls()
+        for elem in self._get_list_of_strs(data, "reserved"):
+            self.mark_reserved(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "known"):
+            self.mark(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "added"):
+            self.add_file(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "changed"):
+            self.change_file(PurePath(elem))
+        for elem in self._get_list_of_strs(data, "deleted"):
+            self.delete_file(PurePath(elem))
+
+        return self
+
+    def store(self, path: Path) -> None:
+        """
+        May raise OSError.
+        """
+
+        data = {
+            "reserved": [str(path) for path in sorted(self.reserved_files)],
+            "known": [str(path) for path in sorted(self.known_files)],
+            "added": [str(path) for path in sorted(self.added_files)],
+            "changed": [str(path) for path in sorted(self.changed_files)],
+            "deleted": [str(path) for path in sorted(self.deleted_files)],
+        }
+
+        with open(path, "w") as f:
+            json.dump(data, f, indent=2, sort_keys=True)
+            f.write("\n")  # json.dump doesn't do this
+
     def mark_reserved(self, path: PurePath) -> None:
         self.reserved_files.add(path)
 
@@ -84,7 +145,7 @@ class Report:
         Unlike mark(), this function accepts any paths.
         """
 
-        self.new_files.add(path)
+        self.added_files.add(path)
 
     def change_file(self, path: PurePath) -> None:
         """