// EnvelopeParser.h

// Declares the cEnvelopeParser class representing a parser for RFC-822 envelope headers, used both in HTTP and in MIME





#pragma once





class cEnvelopeParser
{
public:
	class cCallbacks
	{
	public:
		// Force a virtual destructor in descendants:
		virtual ~cCallbacks() {}

		/** Called when a full header line is parsed */
		virtual void OnHeaderLine(const AString & a_Key, const AString & a_Value) = 0;
	} ;


	cEnvelopeParser(cCallbacks & a_Callbacks);

	/** Parses the incoming data.
	Returns the number of bytes consumed from the input. The bytes not consumed are not part of the envelope header.
	Returns AString::npos on error
	*/
	size_t Parse(const char * a_Data, size_t a_Size);

	/** Makes the parser forget everything parsed so far, so that it can be reused for parsing another datastream */
	void Reset(void);

	/** Returns true if more input is expected for the envelope header */
	bool IsInHeaders(void) const { return m_IsInHeaders; }

	/** Sets the IsInHeaders flag; used by cMultipartParser to simplify the parser initial conditions */
	void SetIsInHeaders(bool a_IsInHeaders) { m_IsInHeaders = a_IsInHeaders; }

public:
	/** Callbacks to call for the various events */
	cCallbacks & m_Callbacks;

	/** Set to true while the parser is still parsing the envelope headers. Once set to true, the parser will not consume any more data. */
	bool m_IsInHeaders;

	/** Buffer for the incoming data until it is parsed */
	AString m_IncomingData;

	/** Holds the last parsed key; used for line-wrapped values */
	AString m_LastKey;

	/** Holds the last parsed value; used for line-wrapped values */
	AString m_LastValue;


	/** Notifies the callback of the key / value stored in m_LastKey / m_LastValue, then erases them */
	void NotifyLast(void);

	/** Parses one line of header data. Returns true if successful */
	bool ParseLine(const char * a_Data, size_t a_Size);
} ;