2 files changed, 281 insertions, 0 deletions
diff --git a/src/LuaEngine/LuaEngine.c b/src/LuaEngine/LuaEngine.c
new file mode 100644
index 0000000..319f408
--- /dev/null
+++ b/src/LuaEngine/LuaEngine.c
@@ -0,0 +1,273 @@
+#include "LuaEngine/LuaEngine.h"
+
+#include "DirectoryWalker/DirectoryWalker.h"
+#include "Dom/Dom.h"
+#include "Logger/Logger.h"
+#include "Logger/LuaLogger.h"
+#include "Path/Path.h"
+#include "Version/Version.h"
+
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+
+typedef enum { SCRIPT_INLINE, SCRIPT_EXTERNAL } ScriptType;
+
+typedef struct {
+  char *source;
+  ScriptType type;
+  unsigned long line;
+} LuaScript;
+
+typedef struct {
+  LuaScript *items;
+  size_t length;
+  size_t capacity;
+} ScriptList;
+
+static int is_lua_element(const xmlNode *node) {
+  return node->type == XML_ELEMENT_NODE &&
+         strcasecmp((const char *)node->name, "lua") == 0;
+}
+
+static char *duplicate_string(const char *value) {
+  size_t length = strlen(value);
+  char *copy = malloc(length + 1);
+
+  if (copy != NULL) {
+    memcpy(copy, value, length + 1);
+  }
+  return copy;
+}
+
+static int grow_script_list(ScriptList *scripts) {
+  size_t larger_capacity;
+  LuaScript *larger_items;
+
+  if (scripts->capacity > SIZE_MAX / (2 * sizeof(*scripts->items))) {
+    return -1;
+  }
+
+  larger_capacity = scripts->capacity == 0 ? 4 : scripts->capacity * 2;
+  larger_items =
+      realloc(scripts->items, larger_capacity * sizeof(*scripts->items));
+  if (larger_items == NULL) {
+    return -1;
+  }
+
+  scripts->items = larger_items;
+  scripts->capacity = larger_capacity;
+  return 0;
+}
+
+static int append_script(ScriptList *scripts, const char *source,
+                         ScriptType type, unsigned long line) {
+  LuaScript *script;
+
+  if (scripts->length == scripts->capacity && grow_script_list(scripts) != 0) {
+    return -1;
+  }
+
+  script = &scripts->items[scripts->length];
+  script->source = duplicate_string(source);
+  if (script->source == NULL) {
+    return -1;
+  }
+
+  script->type = type;
+  script->line = line;
+  ++scripts->length;
+  return 0;
+}
+
+static int collect_script(xmlNode *node, ScriptList *scripts) {
+  xmlChar *source_path = xmlGetProp(node, BAD_CAST "src");
+  xmlChar *code;
+  int result;
+
+  if (source_path != NULL) {
+    result = append_script(scripts, (const char *)source_path, SCRIPT_EXTERNAL,
+                           node->line);
+    xmlFree(source_path);
+    return result;
+  }
+
+  code = xmlNodeGetContent(node);
+  result = append_script(scripts, code == NULL ? "" : (const char *)code,
+                         SCRIPT_INLINE, node->line);
+  xmlFree(code);
+  return result;
+}
+
+static int collect_scripts(xmlNode *node, ScriptList *scripts) {
+  for (; node != NULL; node = node->next) {
+    if (is_lua_element(node)) {
+      if (collect_script(node, scripts) != 0) {
+        return -1;
+      }
+    } else if (collect_scripts(node->children, scripts) != 0) {
+      return -1;
+    }
+  }
+  return 0;
+}
+
+static void free_scripts(ScriptList *scripts) {
+  size_t index;
+
+  for (index = 0; index < scripts->length; ++index) {
+    free(scripts->items[index].source);
+  }
+  free(scripts->items);
+}
+
+static char *make_chunk_name(const char *input_path, unsigned long line) {
+  size_t input_length = strlen(input_path);
+  size_t capacity;
+  char *chunk_name;
+
+  if (input_length > SIZE_MAX - 32) {
+    return NULL;
+  }
+  capacity = input_length + 32;
+  chunk_name = malloc(capacity);
+
+  if (chunk_name != NULL) {
+    snprintf(chunk_name, capacity, "@%s:%lu", input_path, line);
+  }
+  return chunk_name;
+}
+
+static int run_script(lua_State *lua, const LuaScript *script,
+                      const char *input_path) {
+  char *source_path = NULL;
+  char *chunk_name = NULL;
+  const char *display_path;
+  int load_result;
+  int result;
+
+  if (script->type == SCRIPT_EXTERNAL) {
+    source_path = path_resolve_from_file(input_path, script->source);
+    if (source_path == NULL) {
+      logger_error("unable to allocate Lua source path");
+      return -1;
+    }
+    display_path = source_path;
+    load_result = luaL_loadfile(lua, source_path);
+  } else {
+    chunk_name = make_chunk_name(input_path, script->line);
+    if (chunk_name == NULL) {
+      logger_error("unable to allocate Lua chunk name");
+      return -1;
+    }
+    display_path = input_path;
+    load_result = luaL_loadbuffer(lua, script->source, strlen(script->source),
+                                  chunk_name);
+  }
+
+  result = load_result == 0 ? lua_pcall(lua, 0, 0, 0) : load_result;
+  if (result != 0) {
+    const char *message = lua_tostring(lua, -1);
+
+    logger_error("Lua error in %s: %s", display_path,
+                 message == NULL ? "unknown error" : message);
+    lua_pop(lua, 1);
+  }
+
+  free(chunk_name);
+  free(source_path);
+  return result == 0 ? 0 : -1;
+}
+
+static int run_scripts(lua_State *lua, const ScriptList *scripts,
+                       const char *input_path) {
+  size_t index;
+
+  for (index = 0; index < scripts->length; ++index) {
+    if (run_script(lua, &scripts->items[index], input_path) != 0) {
+      return -1;
+    }
+  }
+  return 0;
+}
+
+static void register_yapssg(lua_State *lua) {
+  lua_newtable(lua);
+  lua_pushstring(lua, yapssg_version);
+  lua_setfield(lua, -2, "version");
+  lua_setglobal(lua, "yapssg");
+}
+
+static int replace_document_root(lua_State *lua, htmlDocPtr document,
+                                 const char *input_path) {
+  xmlNodePtr replacement;
+  xmlNodePtr old_root;
+
+  lua_getglobal(lua, "page");
+  if (!lua_istable(lua, -1)) {
+    logger_error("Lua global 'page' must remain a table: %s", input_path);
+    lua_pop(lua, 1);
+    return -1;
+  }
+
+  replacement = dom_page_from_lua(lua, lua_gettop(lua));
+  lua_pop(lua, 1);
+  if (replacement == NULL || replacement->type != XML_ELEMENT_NODE) {
+    logger_error("Lua produced an invalid page root: %s", input_path);
+    xmlFreeNode(replacement);
+    return -1;
+  }
+
+  old_root = xmlDocSetRootElement(document, replacement);
+  xmlFreeNode(old_root);
+  return 0;
+}
+
+int process_html_document(htmlDocPtr document, const char *input_path) {
+  xmlNodePtr root = xmlDocGetRootElement(document);
+  ScriptList scripts = {0};
+  lua_State *lua;
+  int result;
+
+  if (root == NULL) {
+    logger_error("HTML document has no root element: %s", input_path);
+    return -1;
+  }
+  if (collect_scripts(root, &scripts) != 0) {
+    logger_error("unable to collect Lua scripts: %s", input_path);
+    free_scripts(&scripts);
+    return -1;
+  }
+  if (scripts.length == 0) {
+    free_scripts(&scripts);
+    return 0;
+  }
+
+  lua = luaL_newstate();
+  if (lua == NULL) {
+    logger_error("unable to create Lua state");
+    free_scripts(&scripts);
+    return -1;
+  }
+
+  luaL_openlibs(lua);
+  register_yapssg(lua);
+  lua_logger_register(lua);
+  directory_walker_register(lua, input_path);
+  dom_push_page(lua, root);
+  lua_setglobal(lua, "page");
+
+  result = run_scripts(lua, &scripts, input_path);
+  if (result == 0) {
+    result = replace_document_root(lua, document, input_path);
+  }
+
+  lua_close(lua);
+  free_scripts(&scripts);
+  return result;
+}
diff --git a/src/LuaEngine/LuaEngine.h b/src/LuaEngine/LuaEngine.h
new file mode 100644
index 0000000..bd035b9
--- /dev/null
+++ b/src/LuaEngine/LuaEngine.h
@@ -0,0 +1,8 @@
+#ifndef YAPSSG_LUA_ENGINE_H
+#define YAPSSG_LUA_ENGINE_H
+
+#include <libxml/HTMLparser.h>
+
+int process_html_document(htmlDocPtr document, const char *input_path);
+
+#endif