From b84c970fbf3f08825cabf9c5a132e20f868907f1 Mon Sep 17 00:00:00 2001
From: Andrew Murray <radarhere@users.noreply.github.com>
Date: Mon, 10 Jun 2024 19:19:06 +1000
Subject: [PATCH 1/2] Wait until all markers are read to process EXIF

---
 Tests/images/multiple_exif.jpg | Bin 364 -> 391 bytes
 Tests/test_file_jpeg.py        |   2 +-
 src/PIL/JpegImagePlugin.py     |  68 +++++++++++++++++----------------
 3 files changed, 37 insertions(+), 33 deletions(-)

diff --git a/Tests/images/multiple_exif.jpg b/Tests/images/multiple_exif.jpg
index 32e0aa301a94dfa13dc47faeb3071c25a5d8b573..f9f343507e73c5fe2df844deaa5d025f5cd013ec 100644
GIT binary patch
delta 66
zcmaFE)XqFX++5wYA~TJF!Pl2Ti-CcGgMpEekAVru;sIhQAZAF*EGjPf|B!(nqOdqM
NIX^FjVWY7nBLK0l4od(4

delta 39
qcmZo?e#10DT!z=RA~TJFAuY40xa9vs20jS4I5jyxFJ+^jB_jX@Ck-qB

diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
index 18dc752d8bd..342c9e47bd4 100644
--- a/Tests/test_file_jpeg.py
+++ b/Tests/test_file_jpeg.py
@@ -870,7 +870,7 @@ def test_ifd_offset_exif(self) -> None:
 
     def test_multiple_exif(self) -> None:
         with Image.open("Tests/images/multiple_exif.jpg") as im:
-            assert im.info["exif"] == b"Exif\x00\x00firstsecond"
+            assert im.getexif()[270] == "firstsecond"
 
     @mark_if_feature_version(
         pytest.mark.valgrind_known_error, "libjpeg_turbo", "2.0", reason="Known Failing"
diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py
index 4d0b75e77ed..a9a89e58bd7 100644
--- a/src/PIL/JpegImagePlugin.py
+++ b/src/PIL/JpegImagePlugin.py
@@ -159,38 +159,6 @@ def APP(self, marker):
         # plus constant header size
         self.info["mpoffset"] = self.fp.tell() - n + 4
 
-    # If DPI isn't in JPEG header, fetch from EXIF
-    if "dpi" not in self.info and "exif" in self.info:
-        try:
-            exif = self.getexif()
-            resolution_unit = exif[0x0128]
-            x_resolution = exif[0x011A]
-            try:
-                dpi = float(x_resolution[0]) / x_resolution[1]
-            except TypeError:
-                dpi = x_resolution
-            if math.isnan(dpi):
-                msg = "DPI is not a number"
-                raise ValueError(msg)
-            if resolution_unit == 3:  # cm
-                # 1 dpcm = 2.54 dpi
-                dpi *= 2.54
-            self.info["dpi"] = dpi, dpi
-        except (
-            struct.error,
-            KeyError,
-            SyntaxError,
-            TypeError,
-            ValueError,
-            ZeroDivisionError,
-        ):
-            # struct.error for truncated EXIF
-            # KeyError for dpi not included
-            # SyntaxError for invalid/unreadable EXIF
-            # ValueError or TypeError for dpi being an invalid float
-            # ZeroDivisionError for invalid dpi rational value
-            self.info["dpi"] = 72, 72
-
 
 def COM(self: JpegImageFile, marker: int) -> None:
     #
@@ -409,6 +377,8 @@ def _open(self):
                 msg = "no marker found"
                 raise SyntaxError(msg)
 
+        self._read_dpi_from_exif()
+
     def load_read(self, read_bytes: int) -> bytes:
         """
         internal: read more image data
@@ -497,6 +467,40 @@ def load_djpeg(self) -> None:
     def _getexif(self) -> dict[str, Any] | None:
         return _getexif(self)
 
+    def _read_dpi_from_exif(self) -> None:
+        # If DPI isn't in JPEG header, fetch from EXIF
+        if "dpi" in self.info or "exif" not in self.info:
+            return
+        try:
+            exif = self.getexif()
+            resolution_unit = exif[0x0128]
+            x_resolution = exif[0x011A]
+            try:
+                dpi = float(x_resolution[0]) / x_resolution[1]
+            except TypeError:
+                dpi = x_resolution
+            if math.isnan(dpi):
+                msg = "DPI is not a number"
+                raise ValueError(msg)
+            if resolution_unit == 3:  # cm
+                # 1 dpcm = 2.54 dpi
+                dpi *= 2.54
+            self.info["dpi"] = dpi, dpi
+        except (
+            struct.error,
+            KeyError,
+            SyntaxError,
+            TypeError,
+            ValueError,
+            ZeroDivisionError,
+        ):
+            # struct.error for truncated EXIF
+            # KeyError for dpi not included
+            # SyntaxError for invalid/unreadable EXIF
+            # ValueError or TypeError for dpi being an invalid float
+            # ZeroDivisionError for invalid dpi rational value
+            self.info["dpi"] = 72, 72
+
     def _getmp(self):
         return _getmp(self)
 

From 88cd6d41eff702ac83300807b097f6044b665025 Mon Sep 17 00:00:00 2001
From: Andrew Murray <3112309+radarhere@users.noreply.github.com>
Date: Fri, 28 Jun 2024 17:28:42 +1000
Subject: [PATCH 2/2] Rearranged comments

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
---
 src/PIL/JpegImagePlugin.py | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/src/PIL/JpegImagePlugin.py b/src/PIL/JpegImagePlugin.py
index a9a89e58bd7..59259b7194c 100644
--- a/src/PIL/JpegImagePlugin.py
+++ b/src/PIL/JpegImagePlugin.py
@@ -487,18 +487,13 @@ def _read_dpi_from_exif(self) -> None:
                 dpi *= 2.54
             self.info["dpi"] = dpi, dpi
         except (
-            struct.error,
-            KeyError,
-            SyntaxError,
-            TypeError,
-            ValueError,
-            ZeroDivisionError,
+            struct.error,  # truncated EXIF
+            KeyError,  # dpi not included
+            SyntaxError,  # invalid/unreadable EXIF
+            TypeError,  # dpi is an invalid float
+            ValueError,  # dpi is an invalid float
+            ZeroDivisionError,  # invalid dpi rational value
         ):
-            # struct.error for truncated EXIF
-            # KeyError for dpi not included
-            # SyntaxError for invalid/unreadable EXIF
-            # ValueError or TypeError for dpi being an invalid float
-            # ZeroDivisionError for invalid dpi rational value
             self.info["dpi"] = 72, 72
 
     def _getmp(self):