Correcting the previous commit: I claimed VFS placeholders could not be
downloaded. That was wrong. The desktop client exposes a socket at
$XDG_RUNTIME_DIR/Nextcloud/socket speaking newline-delimited
COMMAND:argument, and MAKE_AVAILABLE_LOCALLY:<path> does fetch the file.
Verified against client 4.0.7: a 1-byte stub became a real 2.8MB file in
2.8 seconds.
Implemented as dr-sync-nextcloud::desktop_client, deliberately optional.
Android has no desktop client, no XDG_RUNTIME_DIR socket and no
placeholders, so detect() returns None there and callers fall back to the
connector. It earns its place only because it is ~30 lines with no
dependencies: where a library already lives in a VFS folder, asking the
client to fetch beats downloading a second copy over WebDAV and leaving
the client's placeholder state inconsistent.
What this does not change: hydration is whole-file, so it suits the
original tier and never browsing. Filling a grid this way downloads the
entire library. Range extraction remains the only mechanism satisfying
FR-NC-3, and ARCH §9.0 now says so precisely.
Also fixes two real Android build failures found by cross-compiling:
- reqwest's `rustls` feature defaults to aws-lc-rs, whose aws-lc-sys
crate is C and fails under the NDK — exactly the pain D1 chose Rust
to avoid. Switched to rustls-no-provider + ring, installing the
provider in the constructor so no caller can build a client that
panics on first use.
- ring itself needs CC/AR per target; cargo-ndk sets only the linker.
Added them to the container.
87 tests passing. dr-sync-nextcloud cross-compiles for aarch64-linux-android.
Investigated using the Nextcloud desktop client's Virtual Files as a
cache instead of talking to the server directly. Measured on this
machine (client 4.0.7): the configured folder holds 121,785 placeholders
against 10,267 materialised files, including 7,037 CR2 and 9,411 DNG.
Three findings, each independently disqualifying:
- Linux VFS is *suffix* mode. A dehydrated IMG.CR2 exists only as
IMG.CR2.nextcloud holding one byte; the real name is absent.
- Reading a placeholder does not hydrate it. dd of the first 256KB
returned 1 byte, the stub was unchanged, and the real name never
appeared. There is no FUSE layer — the stub is an inert marker.
- Even with hydration the granularity is wrong: VFS has two states,
1 byte or all bytes, and the preview tier needs a ~256KB prefix of
a 27MB file. That is ~100x what FR-NC-3 requires.
Recorded as ARCH §9.0. Coexistence is still supported: dr-types now
recognises *.nextcloud stubs, and the viewer lists them as "not
downloaded" rather than as corrupt files or not at all.
So the connector talks to the server directly, as D7 specified.
Implemented: Login Flow v2, PROPFIND with oc:fileid and nc:has-preview,
ETag pruning via a Depth:0 probe, range GET with local slicing when the
server ignores the header, conditional PUT, and /core/preview with
forceIcon=false. delta() returns Unsupported and says why.
Chunked upload v2 is not implemented yet — put() rejects bodies over
5MB explicitly rather than silently truncating.
Two bugs found by testing: my hand-computed epoch in a date test was a
day out (the parser was right), and quick-xml reaches EOF on truncated
input without erroring, so unbalanced elements needed an explicit check
— a half-parsed multistatus must not look like an empty directory.
83 tests passing.
Establishes the v0.1 foundations on both platforms:
- dr-types: SourceRef (never a filesystem path — Android SAF has none),
Format, Availability, Validator with ETag quote normalisation
- dr-gpu: wgpu device, compute pass writing a storage texture, resize
- dr-ui: Slint shell with FR-UI-1 adaptive layout, computed in Rust to
avoid a binding loop
- docker/android: pinned toolchain, verified producing API 28 ARM binaries
Measured the cost of the temporary CPU readback path (dr-gpu bench):
compute is 0.06-0.28ms across sizes while readback is 0.63-7.43ms, so
readback is 90-96% of frame time and scales with area. Recorded in
ARCH §6.1 — this is why spike S1 is the priority.
Mitigations pending S1: reuse the staging buffer, apply at most one
resize per frame, and cap render resolution at 2048 on the long edge.
10 tests passing; core crates cross-compile for aarch64-linux-android.
dtourolle