[reports] use gnc:make-split->owner with guardian

Instead of a gnc:split->owner, use gnc:make-split->owner instead which
generates a split->owner function with its own hashtable. This
function (and its hash table) will be garbage collected in due course,
triggering the gncOwnerFreeing of all owners.

This is a better approach than gnc:split->owner which maintains a
single hash table. It could be buggy: a report calls gnc:split->owner
to query a split, fails to reset its hashtable via #f; the split's
owner is assigned or modified, and the next call to gnc:split->owner
will return the incorrect cached owner.

bindings/guile/business-core.scm

@@ -32,6 +32,7 @@
 (export gnc:owner-get-owner-id)
 (export gnc:owner-from-split)
 (export gnc:split->owner)
+(export gnc:make-split->owner)
 
 (define (gnc:owner-get-address owner)
   (let ((type (gncOwnerGetType owner)))
@@ -114,7 +115,7 @@
 (define (gnc:owner-from-split split result-owner)
   (define (notnull x) (and (not (null? x)) x))
   (issue-deprecation-warning
-   "gnc:owner-from-split is deprecated in 4.x. use gnc:split->owner instead.")
+   "gnc:owner-from-split is deprecated in 4.x. use gnc:make-split->owner instead.")
   (let* ((trans (xaccSplitGetParent split))
 	 (invoice (notnull (gncInvoiceGetInvoiceFromTxn trans)))
 	 (temp (gncOwnerNew))
@@ -139,6 +140,8 @@
 (define gnc:split->owner
   (let ((ht (make-hash-table)))
     (lambda (split)
+      (issue-deprecation-warning
+       "gnc:split->owner is deprecated in 4.x. use gnc:make-split->owner instead.")
       (cond
        ((not split)
         (hash-for-each (lambda (k v) (gncOwnerFree v)) ht)
@@ -154,3 +157,33 @@
                           owner))
           (hash-set! ht (gncSplitGetGUID split) owner)
           owner))))))
+
+(define owner-guardian (make-guardian))
+
+(define (reclaim-owners)
+  (let ((owner (owner-guardian)))
+    (when owner
+      (gncOwnerFree owner)
+      (reclaim-owners))))
+
+(add-hook! after-gc-hook reclaim-owners)
+
+;; Create a function which helps find a split's gncOwner. It will
+;; allocate and memoize the owners in a hash table because
+;; gncOwnerGetOwnerFromLot is slow. When the function is out of scope,
+;; and gc is run, the hash table is destroyed and the above hook will
+;; run, releasing the owners via gncOwnerFree.
+(define (gnc:make-split->owner)
+  (let ((ht (make-hash-table)))
+    (lambda (split)
+      (or (hash-ref ht (gncSplitGetGUID split))
+          (let ((lot (xaccSplitGetLot split))
+                (owner (gncOwnerNew)))
+            (unless (gncOwnerGetOwnerFromLot lot owner)
+              (gncOwnerCopy (gncOwnerGetEndOwner
+                             (gncInvoiceGetOwner
+                              (gncInvoiceGetInvoiceFromLot lot)))
+                            owner))
+            (hash-set! ht (gncSplitGetGUID split) owner)
+            (owner-guardian owner)
+            owner)))))

gnucash/report/reports/standard/new-aging.scm

@@ -157,12 +157,6 @@ exist but have no suitable transactions."))
     (not (or (eqv? type TXN-TYPE-INVOICE)
              (eqv? type TXN-TYPE-PAYMENT)))))
 
-(define (split-has-owner? split owner)
-  (gncOwnerEqual (gnc:split->owner split) owner))
-
-(define (split-owner-is-invalid? split)
-  (not (gncOwnerIsValid (gnc:split->owner split))))
-
 (define (split-from-acct? split acct)
   (equal? acct (xaccSplitGetAccount split)))
 
@@ -175,6 +169,14 @@ exist but have no suitable transactions."))
   (define (op-value section name)
     (gnc:option-value (gnc:lookup-option options section name)))
 
+  (define split->owner (gnc:make-split->owner))
+
+  (define (split-has-owner? split owner)
+    (gncOwnerEqual (split->owner split) owner))
+
+  (define (split-owner-is-invalid? split)
+    (not (gncOwnerIsValid (split->owner split))))
+
   (define make-heading-list
     (list (G_ "Company")
           (G_ "Pre-Payment")
@@ -231,10 +233,6 @@ exist but have no suitable transactions."))
       (let* ((splits (xaccQueryGetSplitsUniqueTrans query)))
         (qof-query-destroy query)
 
-        ;; split->owner hashtable should be empty at the start of
-        ;; report renderer. clear it anyway.
-        (gnc:split->owner #f)
-
         ;; loop into each APAR account
         (let loop ((accounts accounts)
                    (splits splits)
@@ -316,7 +314,6 @@ exist but have no suitable transactions."))
                         acc-totals)))))
                  (reverse accounts-and-owners))
 
-                (gnc:split->owner #f)       ;free the gncOwners
                 (gnc:html-document-add-object! document table)
 
                 (unless (null? invalid-splits)
@@ -373,7 +370,7 @@ exist but have no suitable transactions."))
                        owners-and-aging))
 
                   ((this . _)
-                   (match-let* ((owner (gnc:split->owner this))
+                   (match-let* ((owner (split->owner this))
                                 ((owner-splits . other-owner-splits)
                                  (list-split acc-splits split-has-owner? owner))
                                 (aging (gnc:owner-splits->aging-list

gnucash/report/reports/standard/new-owner-report.scm

@@ -1246,13 +1246,11 @@ and do not match the transaction."))))))))
 
 (define (gnc:owner-report-create-internal
          account split query journal? double? title debit-string credit-string)
-
-  (let* ((owner (gnc:split->owner split))
-         (res (if (gncOwnerIsValid owner)
-                  (owner-report-create-with-enddate owner account #f)
-                  -1)))
-    (gnc:split->owner #f)
-    res))
+  (let ((split->owner (gnc:make-split->owner))
+        (owner (split->owner split)))
+    (if (gncOwnerIsValid owner)
+        (owner-report-create-with-enddate owner account #f)
+        -1)))
 
 (gnc:register-report-hook ACCT-TYPE-RECEIVABLE #t gnc:owner-report-create-internal)
 (gnc:register-report-hook ACCT-TYPE-PAYABLE #t gnc:owner-report-create-internal)