forcerecovery.cpp

一个功能强大的内存数据库源代码,c++编写,有详细的注释

#include <stdio.h>
#include <string.h>
#include "fastdb.h"


int main(int argc, char* argv[])
{
    if (argc < 2) { 
	fprintf(stderr, "Usage: forcerecovery [-shadow] [-norecovery] DATABASE-FILE-NAME\n");
	return 1;
    }
    bool swapCurr = false;
    int  dirty = 1;
    FILE* f = NULL;
    for (int i = 1; i < argc; i++) { 
	if (strcmp(argv[i], "-shadow") == 0) { 
	    swapCurr = true;
	} else if (strcmp(argv[i], "-norecovery") == 0) { 
	    dirty = 0;
	} else if (*argv[i] == '-') { 
	    fprintf(stderr, "No such option '%s'\n", argv[i]);
	    return 1;
	} else if (f != NULL) {
	    fprintf(stderr, "File was already specified\n");
	    return 1;
	} else { 
	    f = fopen(argv[i], "r+b");
	    if (f == NULL) { 
		fprintf(stderr, "Failed to open database file '%s'\n", argv[1]);
		return 1;
	    }
	}
    }
    if (f == NULL) { 
	fprintf(stderr, "File was not specified\n");
	return 1;
    }
    dbHeader rec;
    if (fread(&rec, sizeof(dbRecord), 1, f) != 1) { 
	fprintf(stderr, "Failed to read database header\n");
	return 1;
    }
    if (swapCurr) { 
	rec.curr = 1 - rec.curr;
    }
    rec.dirty = dirty;
    fseek(f, 0, 0);
    if (fwrite(&rec, sizeof(dbRecord), 1, f) != 1) { 
	fprintf(stderr, "Failed to write database header\n");
	return 1;
    }
    fclose(f);
    return 0;
}