Use context manager protocol for temporary files

Signed-off-by: Akashdeep Dhar <[email protected]>

gi_loadouts/face/scan/rule.py

@@ -5,7 +5,7 @@
 from gi_loadouts.data.arti import ArtiList
 from gi_loadouts.face.scan.file import file
 from gi_loadouts.face.scan.scan import Ui_scan
-from gi_loadouts.face.scan.util import scanworker
+from gi_loadouts.face.scan.util import scan_artifact
 from gi_loadouts.face.util import truncate_text
 from gi_loadouts.face.wind.talk import Dialog
 from gi_loadouts.type import arti
@@ -171,16 +171,19 @@ def load_reader(self) -> None:
         :return:
         """
         try:
+            self.arti_text.setText("Inspecting screenshot...")
             self.shot, self.path = file.load_screenshot(self, "Select location to load artifact screenshot")
             self.arti_shot.setPixmap(self.shot)
-            area, main, seco, team, levl, rare, duration = scanworker.scan_artifact(self.path)
+            area, main, seco, team, levl, rare, duration = scan_artifact(self.path)
             print(area, main, seco, team, levl, rare, duration)
         except Exception as expt:
             self.show_dialog(
                 QMessageBox.Information,
                 "Faulty scanning",
                 f"Please consider checking your input after ensuring that the proper Tesseract OCR executable has been selected.\n\n{expt}"
             )
+        finally:
+            self.arti_text.setText("Browse your local storage to load a high quality screenshot of your artifact and the statistics will automatically be computed from there.")
 
     def load_tessexec(self) -> None:
         """

gi_loadouts/face/scan/util.py

@@ -1,3 +1,4 @@
+from os import remove
 from os.path import realpath
 from pathlib import Path, PurePath
 from re import search
@@ -16,82 +17,88 @@
 from gi_loadouts.type.stat import ATTR, STAT
 
 
-class ScanWorker:
-    def __init__(self) -> None:
-        file = QFile(":data/data/best.traineddata")
-        if not file.open(QIODevice.ReadOnly):
-            raise FileNotFoundError("Training data for Tesseract OCR could not be initialized")
-        cont = file.readAll()
-        file.close()
-        self.temp = NamedTemporaryFile(delete=False, prefix="gi-loadouts-", suffix=".traineddata")
-        self.temp.write(cont)
-        self.name = Path(self.temp.name).name.replace(".traineddata", "")
-        print(self.name)
-
-    def scan_artifact(self, path: str = "") -> tuple:
-        """
-        Scan the screenshot for computing artifact information using Tesseract OCR
-
-        :return: Collection of artifact information and duration of computation
-        """
-        strttime = time()
-        pytesseract.tesseract_cmd = conf.tessexec
-        imej = Image.open(path)
-        w, h = imej.size
-        l, t, r, b = w // 2, 0, w, h  # noqa: E741
-        imej = imej.crop((l, t, r, b))
-        location = PurePath(realpath(gettempdir())).as_posix()
-        text = image_to_string(imej, lang=self.name, config=f"--tessdata-dir {location}")
-
-        area, main, seco, team, levl, rare = None, ATTR(), list(), "", 0, "Star 0"
-
-        # DISTRIBUTION AREA
-        for ptrn, name in areaiden.items():
+def scan_artifact(path: str = "") -> tuple:
+    """
+    Scan the screenshot for computing artifact information using Tesseract OCR
+
+    :return: Collection of artifact information and duration of computation
+    """
+    strttime = time()
+
+    file = QFile(":data/data/best.traineddata")
+    if not file.open(QIODevice.ReadOnly):
+        raise FileNotFoundError("Training data for Tesseract OCR could not be initialized")
+    cont = file.readAll()
+    file.close()
+
+    area, main, seco, team, levl, rare = None, ATTR(), [ATTR()] * 4, "", "Level 00", "Star 0"
+
+    """
+    When a file is marked for deletion on Windows, the file cannot be reliably opened. Therefore,
+    the context manager protocol for `NamedTemporaryFile` cannot be used here. The temporary file
+    have to be created and deleted manually. On UNIX based operating systems like GNU/Linux or
+    MacOS, files can be reliably opened even when they have been marked for deletion.
+    """
+
+    temp = NamedTemporaryFile(prefix="gi-loadouts-", suffix=".traineddata", delete=False, mode="w+b")
+    temp.write(cont)
+    name = Path(temp.name).name.replace(".traineddata", "")
+
+    pytesseract.tesseract_cmd = conf.tessexec
+    imej = Image.open(path)
+    w, h = imej.size
+    l, t, r, b = w // 2, 0, w, h  # noqa: E741
+    imej = imej.crop((l, t, r, b))
+    location = PurePath(realpath(gettempdir())).as_posix()
+    text = image_to_string(imej, lang=name, config=f"--tessdata-dir {location}")
+
+    # DISTRIBUTION AREA
+    for ptrn, name in areaiden.items():
+        mtch = search(ptrn, text)
+        if mtch:
+            area = name
+
+    # TEAM IDENTITY
+    teamdict = {}
+    for item, coll in teamiden.items():
+        teamdict[item] = 0
+        for sbst in coll:
+            if sbst in text:
+                teamdict[item] += 1
+    sortkeys = sorted(teamdict, key=lambda item: teamdict[item], reverse=True)
+    team = sortkeys[0]
+
+    # RARITY
+    if team.strip() != "":
+        teamobjc = getattr(ArtiList, team.replace(" ", "_").replace("'", "").replace("-", "_"))
+        rare = teamobjc.value.rare[0].value.name
+
+    # MAINSTAT
+    if area == FWOL:
+        main = ATTR(stat_name=STAT.health_points, stat_data=0.0)
+    elif area == PMOD:
+        main = ATTR(stat_name=STAT.attack, stat_data=0.0)
+    elif area in [SDOE, GBOE, CCOL]:
+        for ptrn, name in mainstat[area].items():
             mtch = search(ptrn, text)
             if mtch:
-                area = name
-
-        # TEAM IDENTITY
-        teamdict = {}
-        for item, coll in teamiden.items():
-            teamdict[item] = 0
-            for sbst in coll:
-                if sbst in text:
-                    teamdict[item] += 1
-        sortkeys = sorted(teamdict, key=lambda item: teamdict[item], reverse=True)
-        team = sortkeys[0]
-
-        # RARITY
-        if team.strip() != "":
-            teamobjc = getattr(ArtiList, team.replace(" ", "_").replace("'", "").replace("-", "_"))
-            rare = teamobjc.value.rare[0].value.name
-
-        # MAINSTAT
-        if area == FWOL:
-            main = ATTR(stat_name=STAT.health_points, stat_data=0.0)
-        elif area == PMOD:
-            main = ATTR(stat_name=STAT.attack, stat_data=0.0)
-        elif area in [SDOE, GBOE, CCOL]:
-            for ptrn, name in mainstat[area].items():
-                mtch = search(ptrn, text)
-                if mtch:
-                    main = ATTR(stat_name=name, stat_data=0.0)
-
-        # SUBSTATS
-        for ptrn, name in substats.items():
-            mtch = search(ptrn, text)
-            if mtch and len(seco) < 4:
-                data = search(r"\b\d+(\.\d+)?\b", mtch.group()).group()
-                seco.append(ATTR(stat_name=name, stat_data=float(data)))
+                main = ATTR(stat_name=name, stat_data=0.0)
 
-        # LEVELS
-        mtch = search(levliden, text)
-        if mtch:
-            levl = f"Level {mtch.group()}"
+    # SUBSTATS
+    for ptrn, name in substats.items():
+        mtch = search(ptrn, text)
+        if mtch and len(seco) < 4:
+            data = search(r"\b\d+(\.\d+)?\b", mtch.group()).group()
+            seco.append(ATTR(stat_name=name, stat_data=float(data)))
 
-        stoptime = time()
+    # LEVELS
+    mtch = search(levliden, text)
+    if mtch:
+        levl = f"Level {mtch.group()}"
 
-        return area, main, seco, team, levl, rare, (stoptime - strttime)
+    temp.close()
+    remove(temp.name)
 
+    stoptime = time()
 
-scanworker = ScanWorker()
+    return area, main, seco, team, levl, rare, (stoptime - strttime)