Merge branch 'fix/p1-attrs-links' into fix/p1-read-gaps

# Conflicts:
#	crates/clawhdf5-format/src/attribute.rs
#	crates/clawhdf5-format/src/group_v1.rs
#	crates/clawhdf5/src/lazy.rs
#	crates/clawhdf5/src/mmap_file.rs
#	docs/known-issues.md

crates/clawhdf5-format/src/group_v1.rs

@@ -80,6 +80,53 @@ pub fn find_v1_soft_link(
     offset_size: u8,
     length_size: u8,
 ) -> Result<Option<String>, FormatError> {
+    let mut found = None;
+    for_each_v1_soft_link(
+        file_data,
+        sym_table_msg,
+        offset_size,
+        length_size,
+        |link_name| link_name == name,
+        |_, target| {
+            found = Some(target);
+            false
+        },
+    )?;
+    Ok(found)
+}
+
+/// Every soft link in a v1 group, as `(name, target path)`.
+pub fn v1_soft_links(
+    file_data: &[u8],
+    sym_table_msg: &SymbolTableMessage,
+    offset_size: u8,
+    length_size: u8,
+) -> Result<Vec<(String, String)>, FormatError> {
+    let mut links = Vec::new();
+    for_each_v1_soft_link(
+        file_data,
+        sym_table_msg,
+        offset_size,
+        length_size,
+        |_| true,
+        |name, target| {
+            links.push((String::from(name), target));
+            true
+        },
+    )?;
+    Ok(links)
+}
+
+/// Visit the soft links of a v1 group whose name passes `wanted`, with their
+/// target paths, until `visit` returns false.
+fn for_each_v1_soft_link(
+    file_data: &[u8],
+    sym_table_msg: &SymbolTableMessage,
+    offset_size: u8,
+    length_size: u8,
+    wanted: impl Fn(&str) -> bool,
+    mut visit: impl FnMut(&str, String) -> bool,
+) -> Result<(), FormatError> {
     let heap = LocalHeap::parse(
         file_data,
         sym_table_msg.local_heap_address as usize,
@@ -103,7 +150,8 @@ pub fn find_v1_soft_link(
                 heap.validate_free_list(file_data, length_size)?;
                 heap_checked = true;
             }
-            if heap.read_string(file_data, entry.link_name_offset)? != name {
+            let name = heap.read_string(file_data, entry.link_name_offset)?;
+            if !wanted(&name) {
                 continue;
             }
             let value_offset = u32::from_le_bytes([
@@ -112,12 +160,19 @@ pub fn find_v1_soft_link(
                 entry.scratch_pad[2],
                 entry.scratch_pad[3],
             ]);
-            return heap
-                .read_string(file_data, u64::from(value_offset))
-                .map(Some);
+            let target = heap.read_string(file_data, u64::from(value_offset))?;
+            if !visit(&name, target) {
+                return Ok(());
+            }
         }
     }
-    Ok(None)
+    Ok(())
+}
+
+/// Whether a v1 symbol-table entry is a soft link (no object header of its
+/// own; its target path is in the local heap).
+pub fn is_v1_soft_link(entry: &GroupEntry) -> bool {
+    entry.cache_type == CACHE_TYPE_SOFT_LINK
 }
 
 /// Extract the SymbolTableMessage from an object header's messages.