Implement Block#parse_body in C.

ext/liquid/block.c

@@ -0,0 +1,176 @@
+#include "liquid_ext.h"
+
+extern VALUE mLiquid, cLiquidTokenizer, cLiquidTag, cLiquidTemplate, cLiquidVariable;
+VALUE cLiquidBlock;
+ID intern_assert_missing_delimitation, intern_block_delimiter, intern_is_blank, intern_new,
+   intern_new_with_options, intern_tags, intern_unknown_tag, intern_unterminated_tag,
+   intern_unterminated_variable;
+
+struct liquid_tag
+{
+    char *name, *markup;
+    long name_length, markup_length;
+};
+
+static bool parse_tag(struct liquid_tag *tag, char *token, long token_length)
+{
+    // Strip {{ and }} braces
+    token += 2;
+    token_length -= 4;
+
+    char *end = token + token_length;
+    while (token < end && isspace(*token))
+        token++;
+    tag->name = token;
+
+    char c = *token;
+    while (token < end && (isalnum(c) || c == '_'))
+        c = *(++token);
+    tag->name_length = token - tag->name;
+    if (!tag->name_length) {
+        memset(tag, 0, sizeof(*tag));
+        return false;
+    }
+
+    while (token < end && isspace(*token))
+        token++;
+    tag->markup = token;
+
+    char *last = end - 1;
+    while (token < last && isspace(*last))
+        last--;
+    end = last + 1;
+    tag->markup_length = end - token;
+    return true;
+}
+
+static VALUE rb_parse_body(VALUE self, VALUE tokenizerObj)
+{
+    Check_Type(tokenizerObj, T_DATA);
+    if (RBASIC_CLASS(tokenizerObj) != cLiquidTokenizer) {
+        rb_raise(rb_eTypeError, "wrong argument type %s (expected %s)",
+                 rb_obj_classname(tokenizerObj),
+                 rb_class2name(cLiquidTokenizer));
+    }
+    struct liquid_tokenizer *tokenizer;
+    Data_Get_Struct(tokenizerObj, struct liquid_tokenizer, tokenizer);
+
+    bool blank = true;
+    VALUE nodelist = rb_iv_get(self, "@nodelist");
+    if (nodelist == Qnil) {
+        nodelist = rb_ary_new();
+        rb_iv_set(self, "@nodelist", nodelist);
+    } else {
+        rb_ary_clear(nodelist);
+    }
+
+    struct token token;
+    while (true) {
+        liquid_tokenizer_next(tokenizer, &token);
+        switch (token.type) {
+        case TOKEN_NONE:
+            /*
+             * Make sure that it's ok to end parsing in the current block.
+             * Effectively this method will throw an exception unless the current block is
+             * of type Document
+             */
+            rb_funcall(self, intern_assert_missing_delimitation, 0);
+            goto done;
+        case TOKEN_INVALID:
+        {
+            VALUE token_obj = rb_str_new(token.str, token.length);
+            if (token.str[1] == '%')
+                rb_funcall(self, intern_unterminated_tag, 1, token_obj);
+            else
+                rb_funcall(self, intern_unterminated_variable, 1, token_obj);
+            break;
+        }
+        case TOKEN_TAG:
+        {
+            struct liquid_tag tag;
+            if (!parse_tag(&tag, token.str, token.length)) {
+                // FIXME: provide more appropriate error message
+                rb_funcall(self, intern_unterminated_tag, 1, rb_str_new(token.str, token.length));
+            } else {
+                if (tag.name_length >= 3 && !memcmp(tag.name, "end", 3)) {
+                    VALUE block_delimiter = rb_funcall(self, intern_block_delimiter, 0);
+                    if (TYPE(block_delimiter) == T_STRING &&
+                        tag.name_length == RSTRING_LEN(block_delimiter) &&
+                        !memcmp(tag.name, RSTRING_PTR(block_delimiter), tag.name_length))
+                    {
+                        goto done;
+                    }
+                }
+
+                VALUE tags = rb_funcall(cLiquidTemplate, intern_tags, 0);
+                Check_Type(tags, T_HASH);
+                VALUE tag_name = rb_str_new(tag.name, tag.name_length);
+                VALUE tag_class = rb_hash_lookup(tags, tag_name);
+                VALUE markup = rb_str_new(tag.markup, tag.markup_length);
+                if (tag_class != Qnil) {
+                    VALUE options = rb_iv_get(self, "@options");
+                    if (options == Qnil)
+                        options = rb_hash_new();
+                    VALUE new_tag = rb_funcall(tag_class, intern_new_with_options, 4,
+                                               tag_name, markup, tokenizerObj, options);
+                    if (blank) {
+                        VALUE blank_block = rb_funcall(new_tag, intern_is_blank, 0);
+                        if (blank_block == Qnil || blank_block == Qfalse)
+                            blank = false;
+                    }
+                    rb_ary_push(nodelist, new_tag);
+                } else {
+                    rb_funcall(self, intern_unknown_tag, 3, tag_name, markup, tokenizerObj);
+                    /*
+                     * multi-block tags may store the nodelist in a block array on unknown_tag
+                     * then replace @nodelist with a new array. We need to use the new array
+                     * for the block following the tag token.
+                     */
+                    nodelist = rb_iv_get(self, "@nodelist");
+                }
+            }
+            break;
+        }
+        case TOKEN_VARIABLE:
+        {
+            VALUE markup = rb_str_new(token.str + 2, token.length - 4);
+            VALUE options = rb_iv_get(self, "@options");
+            VALUE new_var = rb_funcall(cLiquidVariable, intern_new, 2, markup, options);
+            rb_ary_push(nodelist, new_var);
+            blank = false;
+            break;
+        }
+        case TOKEN_STRING:
+            rb_ary_push(nodelist, rb_str_new(token.str, token.length));
+            if (blank) {
+                int i;
+                for (i = 0; i < token.length; i++) {
+                    if (!isspace(token.str[i])) {
+                        blank = false;
+                        break;
+                    }
+                }
+            }
+            break;
+        }
+    }
+done:
+    rb_iv_set(self, "@blank", blank ? Qtrue : Qfalse);
+    return Qnil;
+}
+
+void init_liquid_block()
+{
+    intern_assert_missing_delimitation = rb_intern("assert_missing_delimitation!");
+    intern_block_delimiter = rb_intern("block_delimiter");
+    intern_is_blank = rb_intern("blank?");
+    intern_new = rb_intern("new");
+    intern_new_with_options = rb_intern("new_with_options");
+    intern_tags = rb_intern("tags");
+    intern_unknown_tag = rb_intern("unknown_tag");
+    intern_unterminated_tag = rb_intern("unterminated_tag");
+    intern_unterminated_variable = rb_intern("unterminated_variable");
+
+    cLiquidBlock = rb_define_class_under(mLiquid, "Block", cLiquidTag);
+    rb_define_method(cLiquidBlock, "parse_body", rb_parse_body, 1);
+}

ext/liquid/block.h

@@ -0,0 +1,6 @@
+#ifndef LIQUID_BLOCK_H
+#define LIQUID_BLOCK_H
+
+void init_liquid_block();
+
+#endif

ext/liquid/liquid_ext.c

@@ -1,9 +1,15 @@
 #include "liquid_ext.h"
 
 VALUE mLiquid;
+VALUE cLiquidTemplate, cLiquidTag, cLiquidVariable;
 
 void Init_liquid(void)
 {
     mLiquid = rb_define_module("Liquid");
+    cLiquidTemplate = rb_define_class_under(mLiquid, "Template", rb_cObject);
+    cLiquidTag = rb_define_class_under(mLiquid, "Tag", rb_cObject);
+    cLiquidVariable = rb_define_class_under(mLiquid, "Variable", rb_cObject);
+
     init_liquid_tokenizer();
+    init_liquid_block();
 }

ext/liquid/liquid_ext.h

@@ -1,8 +1,11 @@
 #ifndef LIQUID_EXT_H
 #define LIQUID_EXT_H
 
-#include <ruby.h>
 #include <stdbool.h>
+#include <ctype.h>
+#include <ruby.h>
+
 #include "tokenizer.h"
+#include "block.h"
 
 #endif