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client.c
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client.c
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#include <stdlib.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>
#include "table.h"
#include "cursor.h"
#include "btree.h"
typedef struct {
char* buffer;
size_t buffer_size;
ssize_t input_size;
/* data */
} InputBuffer;
typedef enum {
META_COMMAND_SUCCESS,
META_COMMAND_EXIT,
META_COMMAND_INVALID_COMMAND
} MetaCommandResult;
typedef enum {
PREPARE_SUCCESS,
PREPARE_NEGATIVE_ID,
PREPARE_SYNTAX_ERROR,
PREPARE_STRING_TOO_LONG,
PREPARE_UNRECOGNIZED_STATEMENT
} PrepareResult;
typedef enum {
EXECUTE_SUCCESS,
EXECUTE_TABLE_FULL
} ExecuteResult;
typedef enum {
STATEMENT_INSERT,
STATEMENT_SELECT
} StatementType;
typedef struct {
StatementType type;
Row row_data;
} Statement;
InputBuffer* new_input_buffer();
void close_input_buffer(InputBuffer*);
void read_stdin(InputBuffer*);
void print_prompt();
MetaCommandResult do_meta_command(const char*, Table*);
PrepareResult prepare_insert_statement(char*, Statement*);
PrepareResult prepare_statement(char*, Statement*);
ExecuteResult execute_statement(Statement*, Table*);
ExecuteResult execute_insert(Statement*, Table*);
ExecuteResult execute_select(Statement*, Table*);
InputBuffer* new_input_buffer() {
InputBuffer* input_buffer = (InputBuffer*) malloc(sizeof(InputBuffer));
input_buffer->buffer_size = 0;
input_buffer->input_size = 0;
input_buffer->buffer = NULL;
return input_buffer;
}
void close_input_buffer(InputBuffer* input_buffer) {
free(input_buffer->buffer);
free(input_buffer);
}
void read_stdin(InputBuffer* input_buffer) {
ssize_t bytes_read = getline(&(input_buffer->buffer), &(input_buffer->buffer_size), stdin);
if (bytes_read <= 0) {
printf("Error reading input\n");
exit(EXIT_FAILURE);
}
input_buffer->input_size = bytes_read - 1;
input_buffer->buffer[bytes_read - 1] = '\0';
}
void print_prompt() { printf("db > "); }
MetaCommandResult do_meta_command(const char* command, Table* table) {
if (strcmp(command, ":exit") == 0) {
return META_COMMAND_EXIT;
} else if (strcmp(command, ":btree") == 0) {
printf("Tree:\n");
print_leaf_node(get_page(table->pager, 0));
return META_COMMAND_SUCCESS;
} else {
return META_COMMAND_INVALID_COMMAND;
}
}
PrepareResult prepare_insert_statement(char* sql_expr, Statement* statement) {
statement->type = STATEMENT_INSERT;
char* keyword = strtok(sql_expr, " ");
char* id_str = strtok(NULL, " ");
char* username = strtok(NULL, " ");
char* email = strtok(NULL, " ");
if (id_str == NULL || username == NULL || email == NULL) {
return PREPARE_SYNTAX_ERROR;
}
if (strlen(username) > COLUMN_USERNAME_SIZE) {
return PREPARE_STRING_TOO_LONG;
}
if (strlen(email) > COLUMN_EMAIL_SIZE) {
return PREPARE_STRING_TOO_LONG;
}
int id = atoi(id_str);
if (id < 0) { return PREPARE_NEGATIVE_ID; }
statement->row_data.id = id;
strcpy(statement->row_data.username, username);
strcpy(statement->row_data.email, email);
return PREPARE_SUCCESS;
}
PrepareResult prepare_statement(char* sql_expr, Statement* statement) {
if (strncmp(sql_expr, "insert", 6) == 0) {
return prepare_insert_statement(sql_expr, statement);
}
if (strcmp(sql_expr, "select") == 0) {
statement->type = STATEMENT_SELECT;
return PREPARE_SUCCESS;
}
return PREPARE_UNRECOGNIZED_STATEMENT;
}
ExecuteResult execute_statement(Statement* statement, Table* table) {
switch (statement->type) {
case STATEMENT_INSERT:
return execute_insert(statement, table);
case STATEMENT_SELECT:
return execute_select(statement, table);
}
}
ExecuteResult execute_insert(Statement* statement, Table* table) {
if (table_full(table)) {
return EXECUTE_TABLE_FULL;
}
Row* row_data = &(statement->row_data);
//void* dest = locate_row(table, table->num_rows);
Cursor* cursor = table_end(table);
// serialize_row(row_data, cursor_value(cursor));
// table->num_rows += 1;
cursor_insert(cursor, row_data->id, row_data);
free(cursor);
return EXECUTE_SUCCESS;
}
ExecuteResult execute_select(Statement* statement, Table* table) {
Row row;
Cursor* cursor = table_start(table);
while (!(cursor->end_of_table)) {
deserialize_row(cursor_value(cursor), &row);
print_row(&row);
cursor_next(cursor);
}
// for (uint32_t i = 0; i < table->num_rows; i++) {
// deserialize_row(locate_row(table, i), &row);
// print_row(&row);
// }
free(cursor);
return EXECUTE_SUCCESS;
}
int main(int argc, char* argv[]) {
if (argc < 2) {
printf("Must supply a database filename.\n");
exit(EXIT_FAILURE);
}
char* filename = argv[1];
Table* table = open_db(filename);
InputBuffer* input_buffer = new_input_buffer();
bool running = true;
while (running) {
print_prompt();
read_stdin(input_buffer);
if (input_buffer->buffer[0] == ':') {
switch (do_meta_command(input_buffer->buffer, table)){
case META_COMMAND_EXIT:
close_input_buffer(input_buffer);
close_db(table);
printf("Bye.\n");
exit(EXIT_SUCCESS);
case META_COMMAND_SUCCESS:
break;
case META_COMMAND_INVALID_COMMAND:
printf("Invalid command '%s'.\n", input_buffer->buffer);
break;
default: ;;
}
} else {
Statement statement;
switch (prepare_statement(input_buffer->buffer, &statement)) {
case PREPARE_SUCCESS:
break;
case PREPARE_STRING_TOO_LONG:
printf("String is too long.\n");
continue;
case PREPARE_NEGATIVE_ID:
printf("ID must be positive.\n");
continue;
case PREPARE_SYNTAX_ERROR:
printf("Syntax error. Could not parse statement.\n");
continue;
case PREPARE_UNRECOGNIZED_STATEMENT:
printf("Unrecognized keyword at start of '%s'.\n", input_buffer->buffer);
continue;
default: continue;
}
ExecuteResult exec_result = execute_statement(&statement, table);
switch (exec_result) {
case (EXECUTE_SUCCESS):
printf("Executed.\n");
break;
case (EXECUTE_TABLE_FULL):
printf("Error: Table full.\n");
break;
}
}
}
}