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Migrate jsonpull to unique_ptr ownership

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Replaces the shared_ptr-based json_object_ptr with a unique_ptr that
has a stateless custom deleter dispatching on json_object::type before
calling the right subclass destructor. Eliminates per-node atomic
reference-counting and the control-block allocation that shared_ptr
required for every node in the tree.

API now distinguishes owning and borrowing pointers explicitly:
- json_read / json_read_separators / json_hash_get return raw
  json_object * (borrowed from the parser-owned tree).
- json_read_tree / json_disconnect return json_object_ptr (caller
  takes ownership; back-pointers are cleared so the subtree can
  outlive the parser).
- json_free / json_context / json_stringify take raw pointers.
- The parser's container_stack holds raw pointers; jp->root keeps
  unique_ptr ownership of the most recent top-level value.

Internally, take_from_owner moves the unique_ptr out of whichever
parent vector / hash entry / parser root owned it, which both
json_free and json_disconnect rely on.

In the streaming parsers (parse_feature, parse_layers, the
geojson-loop callback), we are careful to free `j` only after we
have processed a complete Feature: json_read returns each token
as the tree is being built up, and freeing an intermediate node
would splice it out of the surrounding hash and corrupt the
in-progress feature.

Benchmark (tl_2022_us_county.json, -z0 --extend-zooms-if-still-dropping,
median of 5 runs on macOS arm64): 8.5s, vs 10.6s with shared_ptr
and 8.7s on the pre-refactor C baseline.

Co-authored-by: Cursor <cursoragent@cursor.com>
This commit is contained in:
Erica Fischer
2026-05-30 20:44:25 -07:00
co-authored by Cursor
parent 1a7075e3ab
commit 65beb3f0d7
23 changed files with 408 additions and 289 deletions
Download Patch File Download Diff File Expand all files Collapse all files
geojson-loop.cpp
+16 -16
View File
@@ -25,7 +25,7 @@ static const char *geometry_names[GEOM_TYPES] = {
};
// XXX duplicated
static void json_context(json_object_ptr j) {
static void json_context(json_object *j) {
std::string s = json_stringify(j);
if (s.size() >= 500) {
@@ -36,18 +36,18 @@ static void json_context(json_object_ptr j) {
fprintf(stderr, "in JSON object %s\n", s.c_str());
}
void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
void parse_json(json_feature_action *jfa, json_pull_ptr &jp) {
long long found_hashes = 0;
long long found_features = 0;
long long found_geometries = 0;
while (1) {
json_object_ptr j = json_read(jp);
json_object *j = json_read(jp);
if (j == nullptr) {
if (jp->error != nullptr) {
fprintf(stderr, "%s:%d: %s: ", jfa->fname.c_str(), jp->line, jp->error);
if (jp->root != nullptr) {
json_context(jp->root);
json_context(jp->root.get());
} else {
fprintf(stderr, "\n");
}
@@ -65,7 +65,7 @@ void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
}
}
json_object_ptr type = json_hash_get(j, "type");
json_object *type = json_hash_get(j, "type");
if (type == nullptr || type->type != JSON_STRING) {
continue;
}
@@ -84,14 +84,14 @@ void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
if (j->parent != nullptr) {
if (j->parent->type == JSON_ARRAY && j->parent->parent != nullptr) {
if (j->parent->parent->type == JSON_HASH) {
json_object_ptr geometries = json_hash_get(j->parent->parent, "geometries");
json_object *geometries = json_hash_get(j->parent->parent, "geometries");
if (geometries != nullptr) {
// Parent of Parent must be a GeometryCollection
is_geometry = 0;
}
}
} else if (j->parent->type == JSON_HASH) {
json_object_ptr geometry = json_hash_get(j->parent, "geometry");
json_object *geometry = json_hash_get(j->parent, "geometry");
if (geometry != nullptr) {
// Parent must be a Feature
is_geometry = 0;
@@ -101,10 +101,10 @@ void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
}
if (is_geometry) {
json_object *jo = j.get();
json_object *jo = j;
while (jo != nullptr) {
if (jo->parent != nullptr && jo->parent->type == JSON_HASH) {
if (json_hash_get(jo->parent, "properties").get() == jo) {
if (json_hash_get(jo->parent, "properties") == jo) {
// Ancestor is the value corresponding to a properties key
is_geometry = 0;
break;
@@ -140,7 +140,7 @@ void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
}
found_features++;
json_object_ptr geometry = json_hash_get(j, "geometry");
json_object *geometry = json_hash_get(j, "geometry");
if (geometry == nullptr) {
fprintf(stderr, "%s:%d: feature with no geometry: ", jfa->fname.c_str(), jp->line);
json_context(j);
@@ -148,7 +148,7 @@ void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
continue;
}
json_object_ptr properties = json_hash_get(j, "properties");
json_object *properties = json_hash_get(j, "properties");
if (properties == nullptr || (properties->type != JSON_HASH && properties->type != JSON_NULL)) {
fprintf(stderr, "%s:%d: feature without properties hash: ", jfa->fname.c_str(), jp->line);
json_context(j);
@@ -158,10 +158,10 @@ void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
bool is_feature = true;
{
json_object *jo = j.get();
json_object *jo = j;
while (jo != nullptr) {
if (jo->parent != nullptr && jo->parent->type == JSON_HASH) {
if (json_hash_get(jo->parent, "properties").get() == jo) {
if (json_hash_get(jo->parent, "properties") == jo) {
// Ancestor is the value corresponding to a properties key
is_feature = false;
break;
@@ -174,10 +174,10 @@ void parse_json(json_feature_action *jfa, json_pull_ptr jp) {
continue;
}
json_object_ptr tippecanoe = json_hash_get(j, "tippecanoe");
json_object_ptr id = json_hash_get(j, "id");
json_object *tippecanoe = json_hash_get(j, "tippecanoe");
json_object *id = json_hash_get(j, "id");
json_object_ptr geometries = json_hash_get(geometry, "geometries");
json_object *geometries = json_hash_get(geometry, "geometries");
if (geometries != nullptr && geometries->type == JSON_ARRAY) {
jfa->add_feature(geometries, true, properties, id, tippecanoe, j);
} else {