1 files changed, 432 insertions, 0 deletions
diff --git a/ext/psych/yaml/loader.c b/ext/psych/yaml/loader.c
new file mode 100644
index 0000000000..9d3d912663
--- /dev/null
+++ b/ext/psych/yaml/loader.c
@@ -0,0 +1,432 @@
+
+#include "yaml_private.h"
+
+/*
+ * API functions.
+ */
+
+YAML_DECLARE(int)
+yaml_parser_load(yaml_parser_t *parser, yaml_document_t *document);
+
+/*
+ * Error handling.
+ */
+
+static int
+yaml_parser_set_composer_error(yaml_parser_t *parser,
+        const char *problem, yaml_mark_t problem_mark);
+
+static int
+yaml_parser_set_composer_error_context(yaml_parser_t *parser,
+        const char *context, yaml_mark_t context_mark,
+        const char *problem, yaml_mark_t problem_mark);
+
+
+/*
+ * Alias handling.
+ */
+
+static int
+yaml_parser_register_anchor(yaml_parser_t *parser,
+        int index, yaml_char_t *anchor);
+
+/*
+ * Clean up functions.
+ */
+
+static void
+yaml_parser_delete_aliases(yaml_parser_t *parser);
+
+/*
+ * Composer functions.
+ */
+
+static int
+yaml_parser_load_document(yaml_parser_t *parser, yaml_event_t *first_event);
+
+static int
+yaml_parser_load_node(yaml_parser_t *parser, yaml_event_t *first_event);
+
+static int
+yaml_parser_load_alias(yaml_parser_t *parser, yaml_event_t *first_event);
+
+static int
+yaml_parser_load_scalar(yaml_parser_t *parser, yaml_event_t *first_event);
+
+static int
+yaml_parser_load_sequence(yaml_parser_t *parser, yaml_event_t *first_event);
+
+static int
+yaml_parser_load_mapping(yaml_parser_t *parser, yaml_event_t *first_event);
+
+/*
+ * Load the next document of the stream.
+ */
+
+YAML_DECLARE(int)
+yaml_parser_load(yaml_parser_t *parser, yaml_document_t *document)
+{
+    yaml_event_t event;
+
+    assert(parser);     /* Non-NULL parser object is expected. */
+    assert(document);   /* Non-NULL document object is expected. */
+
+    memset(document, 0, sizeof(yaml_document_t));
+    if (!STACK_INIT(parser, document->nodes, INITIAL_STACK_SIZE))
+        goto error;
+
+    if (!parser->stream_start_produced) {
+        if (!yaml_parser_parse(parser, &event)) goto error;
+        assert(event.type == YAML_STREAM_START_EVENT);
+                        /* STREAM-START is expected. */
+    }
+
+    if (parser->stream_end_produced) {
+        return 1;
+    }
+
+    if (!yaml_parser_parse(parser, &event)) goto error;
+    if (event.type == YAML_STREAM_END_EVENT) {
+        return 1;
+    }
+
+    if (!STACK_INIT(parser, parser->aliases, INITIAL_STACK_SIZE))
+        goto error;
+
+    parser->document = document;
+
+    if (!yaml_parser_load_document(parser, &event)) goto error;
+
+    yaml_parser_delete_aliases(parser);
+    parser->document = NULL;
+
+    return 1;
+
+error:
+
+    yaml_parser_delete_aliases(parser);
+    yaml_document_delete(document);
+    parser->document = NULL;
+
+    return 0;
+}
+
+/*
+ * Set composer error.
+ */
+
+static int
+yaml_parser_set_composer_error(yaml_parser_t *parser,
+        const char *problem, yaml_mark_t problem_mark)
+{
+    parser->error = YAML_COMPOSER_ERROR;
+    parser->problem = problem;
+    parser->problem_mark = problem_mark;
+
+    return 0;
+}
+
+/*
+ * Set composer error with context.
+ */
+
+static int
+yaml_parser_set_composer_error_context(yaml_parser_t *parser,
+        const char *context, yaml_mark_t context_mark,
+        const char *problem, yaml_mark_t problem_mark)
+{
+    parser->error = YAML_COMPOSER_ERROR;
+    parser->context = context;
+    parser->context_mark = context_mark;
+    parser->problem = problem;
+    parser->problem_mark = problem_mark;
+
+    return 0;
+}
+
+/*
+ * Delete the stack of aliases.
+ */
+
+static void
+yaml_parser_delete_aliases(yaml_parser_t *parser)
+{
+    while (!STACK_EMPTY(parser, parser->aliases)) {
+        yaml_free(POP(parser, parser->aliases).anchor);
+    }
+    STACK_DEL(parser, parser->aliases);
+}
+
+/*
+ * Compose a document object.
+ */
+
+static int
+yaml_parser_load_document(yaml_parser_t *parser, yaml_event_t *first_event)
+{
+    yaml_event_t event;
+
+    assert(first_event->type == YAML_DOCUMENT_START_EVENT);
+                        /* DOCUMENT-START is expected. */
+
+    parser->document->version_directive
+        = first_event->data.document_start.version_directive;
+    parser->document->tag_directives.start
+        = first_event->data.document_start.tag_directives.start;
+    parser->document->tag_directives.end
+        = first_event->data.document_start.tag_directives.end;
+    parser->document->start_implicit
+        = first_event->data.document_start.implicit;
+    parser->document->start_mark = first_event->start_mark;
+
+    if (!yaml_parser_parse(parser, &event)) return 0;
+
+    if (!yaml_parser_load_node(parser, &event)) return 0;
+
+    if (!yaml_parser_parse(parser, &event)) return 0;
+    assert(event.type == YAML_DOCUMENT_END_EVENT);
+                        /* DOCUMENT-END is expected. */
+
+    parser->document->end_implicit = event.data.document_end.implicit;
+    parser->document->end_mark = event.end_mark;
+
+    return 1;
+}
+
+/*
+ * Compose a node.
+ */
+
+static int
+yaml_parser_load_node(yaml_parser_t *parser, yaml_event_t *first_event)
+{
+    switch (first_event->type) {
+        case YAML_ALIAS_EVENT:
+            return yaml_parser_load_alias(parser, first_event);
+        case YAML_SCALAR_EVENT:
+            return yaml_parser_load_scalar(parser, first_event);
+        case YAML_SEQUENCE_START_EVENT:
+            return yaml_parser_load_sequence(parser, first_event);
+        case YAML_MAPPING_START_EVENT:
+            return yaml_parser_load_mapping(parser, first_event);
+        default:
+            assert(0);  /* Could not happen. */
+            return 0;
+    }
+
+    return 0;
+}
+
+/*
+ * Add an anchor.
+ */
+
+static int
+yaml_parser_register_anchor(yaml_parser_t *parser,
+        int index, yaml_char_t *anchor)
+{
+    yaml_alias_data_t data;
+    yaml_alias_data_t *alias_data;
+
+    if (!anchor) return 1;
+
+    data.anchor = anchor;
+    data.index = index;
+    data.mark = parser->document->nodes.start[index-1].start_mark;
+
+    for (alias_data = parser->aliases.start;
+            alias_data != parser->aliases.top; alias_data ++) {
+        if (strcmp((char *)alias_data->anchor, (char *)anchor) == 0) {
+            yaml_free(anchor);
+            return yaml_parser_set_composer_error_context(parser,
+                    "found duplicate anchor; first occurence",
+                    alias_data->mark, "second occurence", data.mark);
+        }
+    }
+
+    if (!PUSH(parser, parser->aliases, data)) {
+        yaml_free(anchor);
+        return 0;
+    }
+
+    return 1;
+}
+
+/*
+ * Compose a node corresponding to an alias.
+ */
+
+static int
+yaml_parser_load_alias(yaml_parser_t *parser, yaml_event_t *first_event)
+{
+    yaml_char_t *anchor = first_event->data.alias.anchor;
+    yaml_alias_data_t *alias_data;
+
+    for (alias_data = parser->aliases.start;
+            alias_data != parser->aliases.top; alias_data ++) {
+        if (strcmp((char *)alias_data->anchor, (char *)anchor) == 0) {
+            yaml_free(anchor);
+            return alias_data->index;
+        }
+    }
+
+    yaml_free(anchor);
+    return yaml_parser_set_composer_error(parser, "found undefined alias",
+            first_event->start_mark);
+}
+
+/*
+ * Compose a scalar node.
+ */
+
+static int
+yaml_parser_load_scalar(yaml_parser_t *parser, yaml_event_t *first_event)
+{
+    yaml_node_t node;
+    int index;
+    yaml_char_t *tag = first_event->data.scalar.tag;
+
+    if (!tag || strcmp((char *)tag, "!") == 0) {
+        yaml_free(tag);
+        tag = yaml_strdup((yaml_char_t *)YAML_DEFAULT_SCALAR_TAG);
+        if (!tag) goto error;
+    }
+
+    SCALAR_NODE_INIT(node, tag, first_event->data.scalar.value,
+            first_event->data.scalar.length, first_event->data.scalar.style,
+            first_event->start_mark, first_event->end_mark);
+
+    if (!PUSH(parser, parser->document->nodes, node)) goto error;
+
+    index = parser->document->nodes.top - parser->document->nodes.start;
+
+    if (!yaml_parser_register_anchor(parser, index,
+                first_event->data.scalar.anchor)) return 0;
+
+    return index;
+
+error:
+    yaml_free(tag);
+    yaml_free(first_event->data.scalar.anchor);
+    yaml_free(first_event->data.scalar.value);
+    return 0;
+}
+
+/*
+ * Compose a sequence node.
+ */
+
+static int
+yaml_parser_load_sequence(yaml_parser_t *parser, yaml_event_t *first_event)
+{
+    yaml_event_t event;
+    yaml_node_t node;
+    struct {
+        yaml_node_item_t *start;
+        yaml_node_item_t *end;
+        yaml_node_item_t *top;
+    } items = { NULL, NULL, NULL };
+    int index, item_index;
+    yaml_char_t *tag = first_event->data.sequence_start.tag;
+
+    if (!tag || strcmp((char *)tag, "!") == 0) {
+        yaml_free(tag);
+        tag = yaml_strdup((yaml_char_t *)YAML_DEFAULT_SEQUENCE_TAG);
+        if (!tag) goto error;
+    }
+
+    if (!STACK_INIT(parser, items, INITIAL_STACK_SIZE)) goto error;
+
+    SEQUENCE_NODE_INIT(node, tag, items.start, items.end,
+            first_event->data.sequence_start.style,
+            first_event->start_mark, first_event->end_mark);
+
+    if (!PUSH(parser, parser->document->nodes, node)) goto error;
+
+    index = parser->document->nodes.top - parser->document->nodes.start;
+
+    if (!yaml_parser_register_anchor(parser, index,
+                first_event->data.sequence_start.anchor)) return 0;
+
+    if (!yaml_parser_parse(parser, &event)) return 0;
+
+    while (event.type != YAML_SEQUENCE_END_EVENT) {
+        item_index = yaml_parser_load_node(parser, &event);
+        if (!item_index) return 0;
+        if (!PUSH(parser,
+                    parser->document->nodes.start[index-1].data.sequence.items,
+                    item_index)) return 0;
+        if (!yaml_parser_parse(parser, &event)) return 0;
+    }
+
+    parser->document->nodes.start[index-1].end_mark = event.end_mark;
+
+    return index;
+
+error:
+    yaml_free(tag);
+    yaml_free(first_event->data.sequence_start.anchor);
+    return 0;
+}
+
+/*
+ * Compose a mapping node.
+ */
+
+static int
+yaml_parser_load_mapping(yaml_parser_t *parser, yaml_event_t *first_event)
+{
+    yaml_event_t event;
+    yaml_node_t node;
+    struct {
+        yaml_node_pair_t *start;
+        yaml_node_pair_t *end;
+        yaml_node_pair_t *top;
+    } pairs = { NULL, NULL, NULL };
+    int index;
+    yaml_node_pair_t pair;
+    yaml_char_t *tag = first_event->data.mapping_start.tag;
+
+    if (!tag || strcmp((char *)tag, "!") == 0) {
+        yaml_free(tag);
+        tag = yaml_strdup((yaml_char_t *)YAML_DEFAULT_MAPPING_TAG);
+        if (!tag) goto error;
+    }
+
+    if (!STACK_INIT(parser, pairs, INITIAL_STACK_SIZE)) goto error;
+
+    MAPPING_NODE_INIT(node, tag, pairs.start, pairs.end,
+            first_event->data.mapping_start.style,
+            first_event->start_mark, first_event->end_mark);
+
+    if (!PUSH(parser, parser->document->nodes, node)) goto error;
+
+    index = parser->document->nodes.top - parser->document->nodes.start;
+
+    if (!yaml_parser_register_anchor(parser, index,
+                first_event->data.mapping_start.anchor)) return 0;
+
+    if (!yaml_parser_parse(parser, &event)) return 0;
+
+    while (event.type != YAML_MAPPING_END_EVENT) {
+        pair.key = yaml_parser_load_node(parser, &event);
+        if (!pair.key) return 0;
+        if (!yaml_parser_parse(parser, &event)) return 0;
+        pair.value = yaml_parser_load_node(parser, &event);
+        if (!pair.value) return 0;
+        if (!PUSH(parser,
+                    parser->document->nodes.start[index-1].data.mapping.pairs,
+                    pair)) return 0;
+        if (!yaml_parser_parse(parser, &event)) return 0;
+    }
+
+    parser->document->nodes.start[index-1].end_mark = event.end_mark;
+
+    return index;
+
+error:
+    yaml_free(tag);
+    yaml_free(first_event->data.mapping_start.anchor);
+    return 0;
+}
+