/*
 * Various trivial helper wrappers around standard functions
 */
#include "cache.h"

static void try_to_free_builtin(size_t size)
{
        release_pack_memory(size, -1);
}

static void (*try_to_free_routine)(size_t size) = try_to_free_builtin;

try_to_free_t set_try_to_free_routine(try_to_free_t routine)
{
        try_to_free_t old = try_to_free_routine;
        try_to_free_routine = routine;
        return old;
}

char *xstrdup(const char *str)
{
        char *ret = strdup(str);
        if (!ret) {
                try_to_free_routine(strlen(str) + 1);
                ret = strdup(str);
                if (!ret)
                        die("Out of memory, strdup failed");
        }
        return ret;
}

void *xmalloc(size_t size)
{
        void *ret = malloc(size);
        if (!ret && !size)
                ret = malloc(1);
        if (!ret) {
                try_to_free_routine(size);
                ret = malloc(size);
                if (!ret && !size)
                        ret = malloc(1);
                if (!ret)
                        die("Out of memory, malloc failed (tried to allocate %lu bytes)",
                            (unsigned long)size);
        }
#ifdef XMALLOC_POISON
        memset(ret, 0xA5, size);
#endif
        return ret;
}

void *xmallocz(size_t size)
{
        void *ret;
        if (size + 1 < size)
                die("Data too large to fit into virtual memory space.");
        ret = xmalloc(size + 1);
        ((char*)ret)[size] = 0;
        return ret;
}

/*
 * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
 * "data" to the allocated memory, zero terminates the allocated memory,
 * and returns a pointer to the allocated memory. If the allocation fails,
 * the program dies.
 */
void *xmemdupz(const void *data, size_t len)
{
        return memcpy(xmallocz(len), data, len);
}

char *xstrndup(const char *str, size_t len)
{
        char *p = memchr(str, '\0', len);
        return xmemdupz(str, p ? p - str : len);
}

void *xrealloc(void *ptr, size_t size)
{
        void *ret = realloc(ptr, size);
        if (!ret && !size)
                ret = realloc(ptr, 1);
        if (!ret) {
                try_to_free_routine(size);
                ret = realloc(ptr, size);
                if (!ret && !size)
                        ret = realloc(ptr, 1);
                if (!ret)
                        die("Out of memory, realloc failed");
        }
        return ret;
}

void *xcalloc(size_t nmemb, size_t size)
{
        void *ret = calloc(nmemb, size);
        if (!ret && (!nmemb || !size))
                ret = calloc(1, 1);
        if (!ret) {
                try_to_free_routine(nmemb * size);
                ret = calloc(nmemb, size);
                if (!ret && (!nmemb || !size))
                        ret = calloc(1, 1);
                if (!ret)
                        die("Out of memory, calloc failed");
        }
        return ret;
}

void *xmmap(void *start, size_t length,
        int prot, int flags, int fd, off_t offset)
{
        void *ret = mmap(start, length, prot, flags, fd, offset);
        if (ret == MAP_FAILED) {
                if (!length)
                        return NULL;
                release_pack_memory(length, fd);
                ret = mmap(start, length, prot, flags, fd, offset);
                if (ret == MAP_FAILED)
                        die_errno("Out of memory? mmap failed");
        }
        return ret;
}

/*
 * xread() is the same a read(), but it automatically restarts read()
 * operations with a recoverable error (EAGAIN and EINTR). xread()
 * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
 */
ssize_t xread(int fd, void *buf, size_t len)
{
        ssize_t nr;
        while (1) {
                nr = read(fd, buf, len);
                if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
                        continue;
                return nr;
        }
}

/*
 * xwrite() is the same a write(), but it automatically restarts write()
 * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
 * GUARANTEE that "len" bytes is written even if the operation is successful.
 */
ssize_t xwrite(int fd, const void *buf, size_t len)
{
        ssize_t nr;
        while (1) {
                nr = write(fd, buf, len);
                if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
                        continue;
                return nr;
        }
}

ssize_t read_in_full(int fd, void *buf, size_t count)
{
        char *p = buf;
        ssize_t total = 0;

        while (count > 0) {
                ssize_t loaded = xread(fd, p, count);
                if (loaded <= 0)
                        return total ? total : loaded;
                count -= loaded;
                p += loaded;
                total += loaded;
        }

        return total;
}

ssize_t write_in_full(int fd, const void *buf, size_t count)
{
        const char *p = buf;
        ssize_t total = 0;

        while (count > 0) {
                ssize_t written = xwrite(fd, p, count);
                if (written < 0)
                        return -1;
                if (!written) {
                        errno = ENOSPC;
                        return -1;
                }
                count -= written;
                p += written;
                total += written;
        }

        return total;
}

int xdup(int fd)
{
        int ret = dup(fd);
        if (ret < 0)
                die_errno("dup failed");
        return ret;
}

FILE *xfdopen(int fd, const char *mode)
{
        FILE *stream = fdopen(fd, mode);
        if (stream == NULL)
                die_errno("Out of memory? fdopen failed");
        return stream;
}

int xmkstemp(char *template)
{
        int fd;

        fd = mkstemp(template);
        if (fd < 0)
                die_errno("Unable to create temporary file");
        return fd;
}

int xmkstemp_mode(char *template, int mode)
{
        int fd;

        fd = git_mkstemp_mode(template, mode);
        if (fd < 0)
                die_errno("Unable to create temporary file");
        return fd;
}

/*
 * zlib wrappers to make sure we don't silently miss errors
 * at init time.
 */
void git_inflate_init(z_streamp strm)
{
        const char *err;

        switch (inflateInit(strm)) {
        case Z_OK:
                return;

        case Z_MEM_ERROR:
                err = "out of memory";
                break;
        case Z_VERSION_ERROR:
                err = "wrong version";
                break;
        default:
                err = "error";
        }
        die("inflateInit: %s (%s)", err, strm->msg ? strm->msg : "no message");
}

void git_inflate_end(z_streamp strm)
{
        if (inflateEnd(strm) != Z_OK)
                error("inflateEnd: %s", strm->msg ? strm->msg : "failed");
}

int git_inflate(z_streamp strm, int flush)
{
        int ret = inflate(strm, flush);
        const char *err;

        switch (ret) {
        /* Out of memory is fatal. */
        case Z_MEM_ERROR:
                die("inflate: out of memory");

        /* Data corruption errors: we may want to recover from them (fsck) */
        case Z_NEED_DICT:
                err = "needs dictionary"; break;
        case Z_DATA_ERROR:
                err = "data stream error"; break;
        case Z_STREAM_ERROR:
                err = "stream consistency error"; break;
        default:
                err = "unknown error"; break;

        /* Z_BUF_ERROR: normal, needs more space in the output buffer */
        case Z_BUF_ERROR:
        case Z_OK:
        case Z_STREAM_END:
                return ret;
        }
        error("inflate: %s (%s)", err, strm->msg ? strm->msg : "no message");
        return ret;
}

int odb_mkstemp(char *template, size_t limit, const char *pattern)
{
        int fd;
        /*
         * we let the umask do its job, don't try to be more
         * restrictive except to remove write permission.
         */
        int mode = 0444;
        snprintf(template, limit, "%s/%s",
                 get_object_directory(), pattern);
        fd = git_mkstemp_mode(template, mode);
        if (0 <= fd)
                return fd;

        /* slow path */
        /* some mkstemp implementations erase template on failure */
        snprintf(template, limit, "%s/%s",
                 get_object_directory(), pattern);
        safe_create_leading_directories(template);
        return xmkstemp_mode(template, mode);
}

int odb_pack_keep(char *name, size_t namesz, unsigned char *sha1)
{
        int fd;

        snprintf(name, namesz, "%s/pack/pack-%s.keep",
                 get_object_directory(), sha1_to_hex(sha1));
        fd = open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
        if (0 <= fd)
                return fd;

        /* slow path */
        safe_create_leading_directories(name);
        return open(name, O_RDWR|O_CREAT|O_EXCL, 0600);
}

static int warn_if_unremovable(const char *op, const char *file, int rc)
{
        if (rc < 0) {
                int err = errno;
                if (ENOENT != err) {
                        warning("unable to %s %s: %s",
                                op, file, strerror(errno));
                        errno = err;
                }
        }
        return rc;
}

int unlink_or_warn(const char *file)
{
        return warn_if_unremovable("unlink", file, unlink(file));
}

int rmdir_or_warn(const char *file)
{
        return warn_if_unremovable("rmdir", file, rmdir(file));
}

int remove_or_warn(unsigned int mode, const char *file)
{
        return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
}