Stub out independent instruction parser.

This commit is contained in:
Michael Jumper 2013-10-01 18:06:19 -07:00
parent fb105b2047
commit 81768daba9
2 changed files with 115 additions and 0 deletions

View File

@ -47,6 +47,50 @@
* @file instruction.h
*/
/**
* The maximum number of bytes per instruction.
*/
#define GUAC_INSTRUCTION_MAX_LENGTH 32768
/**
* The maximum number of digits to allow per length prefix.
*/
#define GUAC_INSTRUCTION_MAX_DIGITS 5
/**
* The maximum number of elements per instruction, including the opcode.
*/
#define GUAC_INSTRUCTION_MAX_ELEMENTS 64
/**
* All possible states of the instruction parser.
*/
typedef enum guac_instruction_parse_state {
/**
* The parser is currently waiting for data to complete the length prefix
* of the current element of the instruction.
*/
GUAC_INSTRUCTION_PARSE_LENGTH,
/**
* The parser has finished reading the length prefix and is currently
* waiting for data to complete the content of the instruction.
*/
GUAC_INSTRUCTION_PARSE_CONTENT,
/**
* The instruction has been fully parsed.
*/
GUAC_INSTRUCTION_PARSE_COMPLETE,
/**
* The instruction cannot be parsed because of a protocol error.
*/
GUAC_INSTRUCTION_PARSE_ERROR
} guac_instruction_parse_state;
/**
* Represents a single instruction within the Guacamole protocol.
*/
@ -67,8 +111,43 @@ typedef struct guac_instruction {
*/
char** argv;
/**
* The parse state of the instruction.
*/
guac_instruction_parse_state state;
/**
* The remaining length of the current element, if known.
*/
int __element_remaining_length;
} guac_instruction;
/**
* Allocates a new instruction. Each instruction contains within itself the
* necessary facilities to parse instruction data.
*
* @return The newly allocated instruction, or NULL if an error occurs during
* allocation, in which case guac_error will be set appropriately.
*/
guac_instruction* guac_instruction_alloc();
/**
* Appends data from the given buffer to the given instruction. The data will
* be appended, if possible, to this instruction as a reference and thus the
* buffer must remain valid throughout the life of the instruction. This
* function may modify the contents of the buffer when those contents are
* part of an element within the instruction being read.
*
* @param instruction The instruction to append data to.
* @param buffer A buffer containing data that should be appended to this
* instruction.
* @param length The number of bytes available for appending within the buffer.
* @return The number of bytes appended to this instruction, which may be
* zero if more data is needed.
*/
int guac_instruction_append(guac_instruction* instruction,
void* buffer, int length);
/**
* Frees all memory allocated to the given instruction.

View File

@ -45,6 +45,42 @@
#include "socket.h"
#include "unicode.h"
guac_instruction* guac_instruction_alloc() {
/* Allocate space for instruction */
guac_instruction* instruction = malloc(sizeof(guac_instruction));
if (instruction == NULL) {
guac_error = GUAC_STATUS_NO_MEMORY;
guac_error_message = "Insufficient memory to allocate instruction";
return NULL;
}
/* Initialize state */
instruction->state = GUAC_INSTRUCTION_PARSE_LENGTH;
return instruction;
}
int guac_instruction_append(guac_instruction* instruction,
void* buffer, int length) {
int bytes_parsed = 0;
/* Parse element length */
if (instruction->state == GUAC_INSTRUCTION_PARSE_LENGTH) {
/* STUB */
}
/* Parse element content */
if (instruction->state == GUAC_INSTRUCTION_PARSE_CONTENT) {
/* STUB */
}
return bytes_parsed;
}
int __guac_fill_instructionbuf(guac_socket* socket) {
int retval;