From 25533558a70ef63c37c70e2352b0ee810cd8200e Mon Sep 17 00:00:00 2001
From: Tethys Svensson <freaken@freaken.dk>
Date: Mon, 13 Jun 2022 10:44:19 +0200
Subject: [PATCH] Update the fix for #99 and some more tests

---
 planus/src/table_reader.rs                    |  30 ++++++++++--------
 test/rust/test_files/issue_99.fbs             |   9 ++++++
 .../issue_99/deserialize/bad-file.bin         | Bin 0 -> 14 bytes
 .../issue_99/deserialize/bad-file.txt         |  14 ++++++++
 .../issue_99/deserialize/issue-99.bin         | Bin 0 -> 20 bytes
 .../issue_99/deserialize/issue-99.txt         |   1 +
 .../issue_99/serialize/non_null.bin           | Bin 0 -> 32 bytes
 .../issue_99/serialize/non_null.dbg.txt       |   4 +++
 .../issue_99/serialize/non_null.dump.txt      |   6 ++++
 .../issue_99/serialize/non_null.json          |   1 +
 .../test_files/issue_99/serialize/null.bin    | Bin 0 -> 12 bytes
 .../issue_99/serialize/null.dbg.txt           |   4 +++
 .../issue_99/serialize/null.dump.txt          |   2 ++
 .../test_files/issue_99/serialize/null.json   |   1 +
 14 files changed, 58 insertions(+), 14 deletions(-)
 create mode 100644 test/rust/test_files/issue_99.fbs
 create mode 100644 test/rust/test_files/issue_99/deserialize/bad-file.bin
 create mode 100644 test/rust/test_files/issue_99/deserialize/bad-file.txt
 create mode 100644 test/rust/test_files/issue_99/deserialize/issue-99.bin
 create mode 100644 test/rust/test_files/issue_99/deserialize/issue-99.txt
 create mode 100644 test/rust/test_files/issue_99/serialize/non_null.bin
 create mode 100644 test/rust/test_files/issue_99/serialize/non_null.dbg.txt
 create mode 100644 test/rust/test_files/issue_99/serialize/non_null.dump.txt
 create mode 100644 test/rust/test_files/issue_99/serialize/non_null.json
 create mode 100644 test/rust/test_files/issue_99/serialize/null.bin
 create mode 100644 test/rust/test_files/issue_99/serialize/null.dbg.txt
 create mode 100644 test/rust/test_files/issue_99/serialize/null.dump.txt
 create mode 100644 test/rust/test_files/issue_99/serialize/null.json

diff --git a/planus/src/table_reader.rs b/planus/src/table_reader.rs
index 7b54ad73..6a9b1714 100644
--- a/planus/src/table_reader.rs
+++ b/planus/src/table_reader.rs
@@ -101,21 +101,23 @@ impl<'buf> Table<'buf> {
             error_kind,
         };
 
-        let offset = self
-            .vtable
-            .get(2 * vtable_offset..2 * (vtable_offset + 2))
-            .ok_or_else(|| make_error(ErrorKind::InvalidOffset))?;
-
-        let tag_offset = u16::from_le_bytes(offset[..2].try_into().unwrap()) as usize;
-        let value_offset = u16::from_le_bytes(offset[2..].try_into().unwrap()) as usize;
-
-        let tag = u8::from_buffer(self.object, tag_offset).map_err(make_error)?;
-        if tag_offset != 0 && value_offset != 0 && tag != 0 {
-            T::from_buffer(self.object, value_offset, tag)
-                .map(Some)
-                .map_err(make_error)
-        } else {
+        if let Some(offset) = self.vtable.get(2 * vtable_offset..2 * (vtable_offset + 2)) {
+            let tag_offset = u16::from_le_bytes(offset[..2].try_into().unwrap()) as usize;
+            let value_offset = u16::from_le_bytes(offset[2..].try_into().unwrap()) as usize;
+            let tag = u8::from_buffer(self.object, tag_offset).map_err(make_error)?;
+            if tag_offset != 0 && value_offset != 0 && tag != 0 {
+                T::from_buffer(self.object, value_offset, tag)
+                    .map(Some)
+                    .map_err(make_error)
+            } else {
+                Ok(None)
+            }
+        } else if self.vtable.len() <= 2 * vtable_offset {
             Ok(None)
+        } else {
+            Err(make_error(ErrorKind::InvalidVtableLength {
+                length: self.vtable.len() as u16 + 4,
+            }))
         }
     }
 
diff --git a/test/rust/test_files/issue_99.fbs b/test/rust/test_files/issue_99.fbs
new file mode 100644
index 00000000..5e40c2b4
--- /dev/null
+++ b/test/rust/test_files/issue_99.fbs
@@ -0,0 +1,9 @@
+table Table {}
+
+union Union {
+  t: Table
+}
+
+table Root {
+  f: Union;
+}
diff --git a/test/rust/test_files/issue_99/deserialize/bad-file.bin b/test/rust/test_files/issue_99/deserialize/bad-file.bin
new file mode 100644
index 0000000000000000000000000000000000000000..826e98787c384564163735f1a1ffa6ab31adc9b2
GIT binary patch
literal 14
Rcmd;LU|?WlU<8v43;+Q302lxO

literal 0
HcmV?d00001

diff --git a/test/rust/test_files/issue_99/deserialize/bad-file.txt b/test/rust/test_files/issue_99/deserialize/bad-file.txt
new file mode 100644
index 00000000..8ec31015
--- /dev/null
+++ b/test/rust/test_files/issue_99/deserialize/bad-file.txt
@@ -0,0 +1,14 @@
+RootRef {
+    f: Err(
+        Error {
+            source_location: ErrorLocation {
+                type_: "Root",
+                method: "f",
+                byte_offset: 10,
+            },
+            error_kind: InvalidVtableLength {
+                length: 6,
+            },
+        },
+    ),
+}
\ No newline at end of file
diff --git a/test/rust/test_files/issue_99/deserialize/issue-99.bin b/test/rust/test_files/issue_99/deserialize/issue-99.bin
new file mode 100644
index 0000000000000000000000000000000000000000..e07cbd4421a407372fb29431e686db73de59dced
GIT binary patch
literal 20
Wcmd;JU|?WjU<6_Y1|A@01Y!UImH;0B

literal 0
HcmV?d00001

diff --git a/test/rust/test_files/issue_99/deserialize/issue-99.txt b/test/rust/test_files/issue_99/deserialize/issue-99.txt
new file mode 100644
index 00000000..a9655539
--- /dev/null
+++ b/test/rust/test_files/issue_99/deserialize/issue-99.txt
@@ -0,0 +1 @@
+RootRef
\ No newline at end of file
diff --git a/test/rust/test_files/issue_99/serialize/non_null.bin b/test/rust/test_files/issue_99/serialize/non_null.bin
new file mode 100644
index 0000000000000000000000000000000000000000..76f9020476d7f2093a162e5ec7e62981004b1c59
GIT binary patch
literal 32
gcmZQ!U|{(2|NnmhAk7HG91NU5%);;oD8>S$0fqtyB>(^b

literal 0
HcmV?d00001

diff --git a/test/rust/test_files/issue_99/serialize/non_null.dbg.txt b/test/rust/test_files/issue_99/serialize/non_null.dbg.txt
new file mode 100644
index 00000000..b4c3e52b
--- /dev/null
+++ b/test/rust/test_files/issue_99/serialize/non_null.dbg.txt
@@ -0,0 +1,4 @@
+Root {
+    f_type: t,
+    f: Table,
+}
\ No newline at end of file
diff --git a/test/rust/test_files/issue_99/serialize/non_null.dump.txt b/test/rust/test_files/issue_99/serialize/non_null.dump.txt
new file mode 100644
index 00000000..e79e82c5
--- /dev/null
+++ b/test/rust/test_files/issue_99/serialize/non_null.dump.txt
@@ -0,0 +1,6 @@
+obj    @ 0x04..0x0d
+vtable @ 0x10..0x18
+field[0] @ 0x0c..0x0d:
+  01
+field[1] @ 0x08..0x0c:
+  10 00 00 00
diff --git a/test/rust/test_files/issue_99/serialize/non_null.json b/test/rust/test_files/issue_99/serialize/non_null.json
new file mode 100644
index 00000000..ee786477
--- /dev/null
+++ b/test/rust/test_files/issue_99/serialize/non_null.json
@@ -0,0 +1 @@
+{"f": {"T": {}}}
diff --git a/test/rust/test_files/issue_99/serialize/null.bin b/test/rust/test_files/issue_99/serialize/null.bin
new file mode 100644
index 0000000000000000000000000000000000000000..080d01d9571840315eecad380818df0aabdc6fc7
GIT binary patch
literal 12
TcmZQ!U|{(3|Nnm$1{MYY8X^P+

literal 0
HcmV?d00001

diff --git a/test/rust/test_files/issue_99/serialize/null.dbg.txt b/test/rust/test_files/issue_99/serialize/null.dbg.txt
new file mode 100644
index 00000000..358684f0
--- /dev/null
+++ b/test/rust/test_files/issue_99/serialize/null.dbg.txt
@@ -0,0 +1,4 @@
+Root {
+    f_type: NONE,
+    f: None,
+}
\ No newline at end of file
diff --git a/test/rust/test_files/issue_99/serialize/null.dump.txt b/test/rust/test_files/issue_99/serialize/null.dump.txt
new file mode 100644
index 00000000..94cbf97b
--- /dev/null
+++ b/test/rust/test_files/issue_99/serialize/null.dump.txt
@@ -0,0 +1,2 @@
+obj    @ 0x04..0x08
+vtable @ 0x08..0x0c
diff --git a/test/rust/test_files/issue_99/serialize/null.json b/test/rust/test_files/issue_99/serialize/null.json
new file mode 100644
index 00000000..b21790b2
--- /dev/null
+++ b/test/rust/test_files/issue_99/serialize/null.json
@@ -0,0 +1 @@
+{"f": null}