[llvm] [Minidump] Support multiple exceptions in a minidump (PR #107319)

[Pavel Labath via llvm-commits]

================
@@ -216,8 +219,68 @@ class MinidumpFile : public Binary {
     bool IsEnd;
   };
 
+  class ExceptionStreamsIterator {
+  public:
+    static ExceptionStreamsIterator begin(ArrayRef<minidump::Directory> Streams,
+                                          const MinidumpFile *File) {
+      return ExceptionStreamsIterator(Streams, File);
+    }
+
+    static ExceptionStreamsIterator end() { return ExceptionStreamsIterator(); }
+
+    bool operator==(const ExceptionStreamsIterator &R) const {
+      return Streams.empty() && R.Streams.empty();
+    }
+
+    bool operator!=(const ExceptionStreamsIterator &R) const {
+      return !(*this == R);
+    }
+
+    Expected<const minidump::ExceptionStream &> operator*() {
+      return ReadCurrent();
+    }
+
+    Expected<const minidump::ExceptionStream &> operator->() {
+      return ReadCurrent();
+    }
+
+    ExceptionStreamsIterator &operator++() {
+      if (!Streams.empty())
+        Streams = Streams.drop_front();
+
+      return *this;
+    }
+
+  private:
+    ExceptionStreamsIterator(ArrayRef<minidump::Directory> Streams,
+                             const MinidumpFile *File)
+        : Streams(Streams), File(File) {}
+
+    ExceptionStreamsIterator()
+        : Streams(ArrayRef<minidump::Directory>()), File(nullptr) {}
+
+    ArrayRef<minidump::Directory> Streams;
+    const MinidumpFile *File;
+
+    Expected<const minidump::ExceptionStream &> ReadCurrent() {
+      assert(!Streams.empty());
+      Expected<const minidump::ExceptionStream &> ExceptionStream =
+          File->getExceptionStream(Streams.front());
+      if (!ExceptionStream)
+        return ExceptionStream.takeError();
+
+      return ExceptionStream;
----------------
labath wrote:

```suggestion
      return File->getExceptionStream(Streams.front());
```

and maybe even get rid of this function?

https://github.com/llvm/llvm-project/pull/107319