jsxmin_renaming.h
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	#ifndef _JSXMIN_RENAMING_H_
	#define _JSXMIN_RENAMING_H_

	#include "abstract_compiler_pass.h"
	#include "libfbjs/node.hpp"
	#include "reduce.hpp"

	#include <string>
	#include <map>
	#include <set>

	using namespace std;

	// A helper class to regenerate variable names.
	class NameFactory {
	public:
	NameFactory() : _current("a"), _prefix("") {}
	NameFactory(const string& prefix) : _current("a"), _prefix(prefix) {}

	// Allows prefix to be reset.
	void set_prefix(const string& prefix) {
	_prefix = prefix;
	}

	string next();

	private:
	string _current;
	string _prefix;
	};

	// A class represent a JavaScript variable naming scope.
	typedef map<string, string> rename_t;
	typedef set<string> names_t;

	class Scope {
	public:
	explicit Scope(Scope* parent) : _parent(parent) {}
	virtual ~Scope() {}

	virtual bool is_global() { return false; }

	// Declares a variable name in the current scope.
	// Called when seeing a variable/function declaration.
	void declare(string name);

	// Checks whether a variable name is declared in the scope chain.
	bool declared(string name);

	// Prevents a variable name from being renamed.
	void reserve(const string& name) {
	rename_internal(name, name);
	}

	// Rename variables declared in this scope using information
	// in the scope chain.
	virtual void rename_vars() = 0;

	// Checks whether a name is taken in the renaming process.
	bool in_use(string name);

	// Returns new name of an original variable name after renaming.
	// Note that renaming process is performed in rename_vars function.
	// This function returns the renaming result.
	string new_name(string orig_name);

	void dump();

	protected:
	// A helper function assigns a new name to an existing variable name.
	void rename_internal(const string& var_name, const string& new_name) {
	_replacement[var_name] = new_name;
	_new_names.insert(new_name);
	}

	// Local variables and rename mapping.
	rename_t _replacement;

	// A cache of new names
	names_t _new_names;

	// Note that, _parent is not ref counted, it assumes that a scope is
	// associated with a stack, so the parent scope always outlives child
	// scopes.
	Scope* _parent;
	};

	// A class representing a local variable naming scope.
	class LocalScope : public Scope {
	public:
	explicit LocalScope(Scope* parent) : Scope(parent) {}
	virtual void rename_vars();
	private:
	bool need_rename(const string& var_name);
	};


	// A class representing a global variable naming scope.
	class GlobalScope : public Scope {
	public:
	GlobalScope(bool rename_private);
	virtual void rename_vars();

	virtual bool is_global() { return true; }

	// Checks whether a variable name should be renamed.
	bool need_rename(const string& var_name);

	void rename_var(const string& var_name);

	private:
	bool _rename_private;
	NameFactory _name_factory;
	};

	class VariableRenaming : public fbjs::AbstractCompilerPass {
	public:
	VariableRenaming();
	virtual ~VariableRenaming();

	// Overrides Compiler::Pass::process
	virtual void process(fbjs::NodeProgram* root);

	private:
	// Minifies variable names in a subtree rooted from node using the current
	// local scope and file scope info. The last parameter decides which
	// scope should be used.
	void minify(fbjs::Node* node, Scope* scope);

	// Build a local scope from a root node (typically a function node)
	void build_scope(fbjs::Node* node, Scope* scope);

	// Checks if a function contains 'with' or 'eval' statements.
	bool function_has_with_or_eval(fbjs::Node* node);

	// Generates a new (shorter) id based on the current scope.
	string generate_id(const char t, const Scope* scope, const string& orig_name);

	GlobalScope* _global_scope;
	};


	// Rename properties, unsafe.
	class PropertyRenaming : public fbjs::AbstractCompilerPass {
	public:
	PropertyRenaming();
	virtual ~PropertyRenaming();

	virtual void process(fbjs::NodeProgram* root);

	private:
	void minify(fbjs::Node* node);
	GlobalScope* _property_scope;
	};

	#endif

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