All public qcow functions now return BlockResult with explicit error
classification at every site. The temporary From impl introduced in
the first commit of this series is no longer needed and is removed.
Internal functions in header.rs and the rebuild_refcounts helpers
stay on qcow::Result. Classification happens at the call site
boundary where qcow::Result meets BlockResult.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Switch parse_qcow and BackingFile::new from qcow::Result to
BlockResult. Every early return site now produces an explicit
BlockError with the appropriate kind. Remaining internal calls to
functions still on qcow::Result rely on the From scaffolding and
will be converted in subsequent commits.
Two helpers are added to BlockError. with_kind replaces the
classification on an existing error, used in QcowDiskSync::new to
avoid double wrapping when the caller needs a different kind.
into_source consumes the error and returns the boxed source, used
at the recursive BackingFile open to extract the qcow::Error for
BackingFileOpen without letting qcow::Error hold a BlockError.
The qcow_sync boundary is simplified to a single closure that
operates on the BlockError already returned by parse_qcow.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Temporary From impl that classifies each qcow::Error variant into
the appropriate BlockErrorKind. This enables an incremental migration
of qcow functions from qcow::Result to BlockResult, where each
subsequent commit replaces bare ? sites with explicit BlockError::new
calls until this impl can be removed.
The mapping assigns InvalidFormat for structural header violations,
UnsupportedFeature for version and feature mismatches, CorruptImage
for internal inconsistencies, Overflow for nesting depth and Io for
everything else.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add ErrorOp::Resize variant and implement the Resizable trait.
Resize is rejected when a backing file is present.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add the public BlockResult type alias and a From<io::Error>
impl so that bare I/O errors automatically convert into
BlockError with BlockErrorKind::Io via the ? operator.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add the construction and inspection API for BlockError,
consisting on constructors that accept a kind and optional
source, builder methods that attach context after
the fact, and accessors for retrieving the kind, context,
and typed source references. The builder pattern allows
callers to enrich errors at each level of the call stack.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add the single public crate error type. It combines a
BlockErrorKind for classification, an optional boxed source
for the underlying cause, and an optional ErrorContext for
diagnostics. Display renders the kind and context only,
leaving source traversal to error reporters so the cause
chain is not duplicated in human readable output.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add a struct that carries optional diagnostic metadata - file
path, byte offset, and operation name that can be attached
to any BlockError. This lets errors report *where* and *during
what* a failure occurred, which is especially useful when the
same I/O kind shows up at multiple call sites.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Add a small, stable enum that classifies block errors into
broad categories - I/O, invalid format, unsupported feature,
corrupt image, out of bounds, not found, overflow. Callers
match on this for control flow rather than on format specific
error variants.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
Introduce error.rs as the home for a unified error hierarchy that
will replace the per format error types at the public crate
boundary. This commit is intentionally empty beyond the copyright
header and module declaration in lib.rs.
Signed-off-by: Anatol Belski <anbelski@linux.microsoft.com>
