Teach bash completion about 'git remote update'
[gitweb.git] / read-cache.c
index 6339a278da1ae1b323b5abf7d2604c7afdfde4e4..d9f46da5cc547d8cfaa34c901be50a13995b120e 100644 (file)
@@ -3,8 +3,10 @@
  *
  * Copyright (C) Linus Torvalds, 2005
  */
+#define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "cache-tree.h"
+#include "refs.h"
 
 /* Index extensions.
  *
 #define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) )
 #define CACHE_EXT_TREE 0x54524545      /* "TREE" */
 
-struct cache_entry **active_cache;
-static time_t index_file_timestamp;
-unsigned int active_nr, active_alloc, active_cache_changed;
-
-struct cache_tree *active_cache_tree;
-
-int cache_errno;
-
-static void *cache_mmap;
-static size_t cache_mmap_size;
+struct index_state the_index;
 
 /*
  * This only updates the "non-critical" parts of the directory
@@ -93,6 +86,23 @@ static int ce_compare_link(struct cache_entry *ce, size_t expected_size)
        return match;
 }
 
+static int ce_compare_gitlink(struct cache_entry *ce)
+{
+       unsigned char sha1[20];
+
+       /*
+        * We don't actually require that the .git directory
+        * under DIRLNK directory be a valid git directory. It
+        * might even be missing (in case nobody populated that
+        * sub-project).
+        *
+        * If so, we consider it always to match.
+        */
+       if (resolve_gitlink_ref(ce->name, "HEAD", sha1) < 0)
+               return 0;
+       return hashcmp(sha1, ce->sha1);
+}
+
 static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
 {
        switch (st->st_mode & S_IFMT) {
@@ -104,6 +114,9 @@ static int ce_modified_check_fs(struct cache_entry *ce, struct stat *st)
                if (ce_compare_link(ce, xsize_t(st->st_size)))
                        return DATA_CHANGED;
                break;
+       case S_IFDIR:
+               if (S_ISDIRLNK(ntohl(ce->ce_mode)))
+                       return 0;
        default:
                return TYPE_CHANGED;
        }
@@ -129,6 +142,12 @@ static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
                    (has_symlinks || !S_ISREG(st->st_mode)))
                        changed |= TYPE_CHANGED;
                break;
+       case S_IFDIRLNK:
+               if (!S_ISDIR(st->st_mode))
+                       changed |= TYPE_CHANGED;
+               else if (ce_compare_gitlink(ce))
+                       changed |= DATA_CHANGED;
+               return changed;
        default:
                die("internal error: ce_mode is %o", ntohl(ce->ce_mode));
        }
@@ -171,7 +190,8 @@ static int ce_match_stat_basic(struct cache_entry *ce, struct stat *st)
        return changed;
 }
 
-int ce_match_stat(struct cache_entry *ce, struct stat *st, int options)
+int ie_match_stat(struct index_state *istate,
+                 struct cache_entry *ce, struct stat *st, int options)
 {
        unsigned int changed;
        int ignore_valid = options & 01;
@@ -203,8 +223,8 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st, int options)
         * carefully than others.
         */
        if (!changed &&
-           index_file_timestamp &&
-           index_file_timestamp <= ntohl(ce->ce_mtime.sec)) {
+           istate->timestamp &&
+           istate->timestamp <= ntohl(ce->ce_mtime.sec)) {
                if (assume_racy_is_modified)
                        changed |= DATA_CHANGED;
                else
@@ -214,10 +234,11 @@ int ce_match_stat(struct cache_entry *ce, struct stat *st, int options)
        return changed;
 }
 
-int ce_modified(struct cache_entry *ce, struct stat *st, int really)
+int ie_modified(struct index_state *istate,
+               struct cache_entry *ce, struct stat *st, int really)
 {
        int changed, changed_fs;
-       changed = ce_match_stat(ce, st, really);
+       changed = ie_match_stat(istate, ce, st, really);
        if (!changed)
                return 0;
        /*
@@ -285,15 +306,15 @@ int cache_name_compare(const char *name1, int flags1, const char *name2, int fla
        return 0;
 }
 
-int cache_name_pos(const char *name, int namelen)
+int index_name_pos(struct index_state *istate, const char *name, int namelen)
 {
        int first, last;
 
        first = 0;
-       last = active_nr;
+       last = istate->cache_nr;
        while (last > first) {
                int next = (last + first) >> 1;
-               struct cache_entry *ce = active_cache[next];
+               struct cache_entry *ce = istate->cache[next];
                int cmp = cache_name_compare(name, namelen, ce->name, ntohs(ce->ce_flags));
                if (!cmp)
                        return next;
@@ -307,27 +328,29 @@ int cache_name_pos(const char *name, int namelen)
 }
 
 /* Remove entry, return true if there are more entries to go.. */
-int remove_cache_entry_at(int pos)
+int remove_index_entry_at(struct index_state *istate, int pos)
 {
-       active_cache_changed = 1;
-       active_nr--;
-       if (pos >= active_nr)
+       istate->cache_changed = 1;
+       istate->cache_nr--;
+       if (pos >= istate->cache_nr)
                return 0;
-       memmove(active_cache + pos, active_cache + pos + 1, (active_nr - pos) * sizeof(struct cache_entry *));
+       memmove(istate->cache + pos,
+               istate->cache + pos + 1,
+               (istate->cache_nr - pos) * sizeof(struct cache_entry *));
        return 1;
 }
 
-int remove_file_from_cache(const char *path)
+int remove_file_from_index(struct index_state *istate, const char *path)
 {
-       int pos = cache_name_pos(path, strlen(path));
+       int pos = index_name_pos(istate, path, strlen(path));
        if (pos < 0)
                pos = -pos-1;
-       while (pos < active_nr && !strcmp(active_cache[pos]->name, path))
-               remove_cache_entry_at(pos);
+       while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path))
+               remove_index_entry_at(istate, pos);
        return 0;
 }
 
-int add_file_to_index(const char *path, int verbose)
+int add_file_to_index(struct index_state *istate, const char *path, int verbose)
 {
        int size, namelen;
        struct stat st;
@@ -336,10 +359,14 @@ int add_file_to_index(const char *path, int verbose)
        if (lstat(path, &st))
                die("%s: unable to stat (%s)", path, strerror(errno));
 
-       if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode))
-               die("%s: can only add regular files or symbolic links", path);
+       if (!S_ISREG(st.st_mode) && !S_ISLNK(st.st_mode) && !S_ISDIR(st.st_mode))
+               die("%s: can only add regular files, symbolic links or git-directories", path);
 
        namelen = strlen(path);
+       if (S_ISDIR(st.st_mode)) {
+               while (namelen && path[namelen-1] == '/')
+                       namelen--;
+       }
        size = cache_entry_size(namelen);
        ce = xcalloc(1, size);
        memcpy(ce->name, path, namelen);
@@ -353,19 +380,19 @@ int add_file_to_index(const char *path, int verbose)
                 * from it, otherwise assume unexecutable regular file.
                 */
                struct cache_entry *ent;
-               int pos = cache_name_pos(path, namelen);
+               int pos = index_name_pos(istate, path, namelen);
 
-               ent = (0 <= pos) ? active_cache[pos] : NULL;
+               ent = (0 <= pos) ? istate->cache[pos] : NULL;
                ce->ce_mode = ce_mode_from_stat(ent, st.st_mode);
        }
 
        if (index_path(ce->sha1, path, &st, 1))
                die("unable to index file %s", path);
-       if (add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
+       if (add_index_entry(istate, ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE))
                die("unable to add %s to index",path);
        if (verbose)
                printf("add '%s'\n", path);
-       cache_tree_invalidate_path(active_cache_tree, path);
+       cache_tree_invalidate_path(istate->cache_tree, path);
        return 0;
 }
 
@@ -469,15 +496,16 @@ int verify_path(const char *path)
  * Do we have another file that has the beginning components being a
  * proper superset of the name we're trying to add?
  */
-static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replace)
+static int has_file_name(struct index_state *istate,
+                        const struct cache_entry *ce, int pos, int ok_to_replace)
 {
        int retval = 0;
        int len = ce_namelen(ce);
        int stage = ce_stage(ce);
        const char *name = ce->name;
 
-       while (pos < active_nr) {
-               struct cache_entry *p = active_cache[pos++];
+       while (pos < istate->cache_nr) {
+               struct cache_entry *p = istate->cache[pos++];
 
                if (len >= ce_namelen(p))
                        break;
@@ -487,10 +515,12 @@ static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replac
                        continue;
                if (p->name[len] != '/')
                        continue;
+               if (!ce_stage(p) && !p->ce_mode)
+                       continue;
                retval = -1;
                if (!ok_to_replace)
                        break;
-               remove_cache_entry_at(--pos);
+               remove_index_entry_at(istate, --pos);
        }
        return retval;
 }
@@ -499,7 +529,8 @@ static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replac
  * Do we have another file with a pathname that is a proper
  * subset of the name we're trying to add?
  */
-static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace)
+static int has_dir_name(struct index_state *istate,
+                       const struct cache_entry *ce, int pos, int ok_to_replace)
 {
        int retval = 0;
        int stage = ce_stage(ce);
@@ -517,28 +548,39 @@ static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace
                }
                len = slash - name;
 
-               pos = cache_name_pos(name, ntohs(create_ce_flags(len, stage)));
+               pos = index_name_pos(istate, name, ntohs(create_ce_flags(len, stage)));
                if (pos >= 0) {
-                       retval = -1;
-                       if (!ok_to_replace)
-                               break;
-                       remove_cache_entry_at(pos);
-                       continue;
+                       /*
+                        * Found one, but not so fast.  This could
+                        * be a marker that says "I was here, but
+                        * I am being removed".  Such an entry is
+                        * not a part of the resulting tree, and
+                        * it is Ok to have a directory at the same
+                        * path.
+                        */
+                       if (stage || istate->cache[pos]->ce_mode) {
+                               retval = -1;
+                               if (!ok_to_replace)
+                                       break;
+                               remove_index_entry_at(istate, pos);
+                               continue;
+                       }
                }
+               else
+                       pos = -pos-1;
 
                /*
                 * Trivial optimization: if we find an entry that
                 * already matches the sub-directory, then we know
                 * we're ok, and we can exit.
                 */
-               pos = -pos-1;
-               while (pos < active_nr) {
-                       struct cache_entry *p = active_cache[pos];
+               while (pos < istate->cache_nr) {
+                       struct cache_entry *p = istate->cache[pos];
                        if ((ce_namelen(p) <= len) ||
                            (p->name[len] != '/') ||
                            memcmp(p->name, name, len))
                                break; /* not our subdirectory */
-                       if (ce_stage(p) == stage)
+                       if (ce_stage(p) == stage && (stage || p->ce_mode))
                                /* p is at the same stage as our entry, and
                                 * is a subdirectory of what we are looking
                                 * at, so we cannot have conflicts at our
@@ -560,34 +602,45 @@ static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace
  * from the cache so the caller should recompute the insert position.
  * When this happens, we return non-zero.
  */
-static int check_file_directory_conflict(const struct cache_entry *ce, int pos, int ok_to_replace)
+static int check_file_directory_conflict(struct index_state *istate,
+                                        const struct cache_entry *ce,
+                                        int pos, int ok_to_replace)
 {
+       int retval;
+
+       /*
+        * When ce is an "I am going away" entry, we allow it to be added
+        */
+       if (!ce_stage(ce) && !ce->ce_mode)
+               return 0;
+
        /*
         * We check if the path is a sub-path of a subsequent pathname
         * first, since removing those will not change the position
-        * in the array
+        * in the array.
         */
-       int retval = has_file_name(ce, pos, ok_to_replace);
+       retval = has_file_name(istate, ce, pos, ok_to_replace);
+
        /*
         * Then check if the path might have a clashing sub-directory
         * before it.
         */
-       return retval + has_dir_name(ce, pos, ok_to_replace);
+       return retval + has_dir_name(istate, ce, pos, ok_to_replace);
 }
 
-int add_cache_entry(struct cache_entry *ce, int option)
+int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option)
 {
        int pos;
        int ok_to_add = option & ADD_CACHE_OK_TO_ADD;
        int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE;
        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
 
-       pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
+       pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags));
 
        /* existing match? Just replace it. */
        if (pos >= 0) {
-               active_cache_changed = 1;
-               active_cache[pos] = ce;
+               istate->cache_changed = 1;
+               istate->cache[pos] = ce;
                return 0;
        }
        pos = -pos-1;
@@ -596,10 +649,10 @@ int add_cache_entry(struct cache_entry *ce, int option)
         * Inserting a merged entry ("stage 0") into the index
         * will always replace all non-merged entries..
         */
-       if (pos < active_nr && ce_stage(ce) == 0) {
-               while (ce_same_name(active_cache[pos], ce)) {
+       if (pos < istate->cache_nr && ce_stage(ce) == 0) {
+               while (ce_same_name(istate->cache[pos], ce)) {
                        ok_to_add = 1;
-                       if (!remove_cache_entry_at(pos))
+                       if (!remove_index_entry_at(istate, pos))
                                break;
                }
        }
@@ -610,25 +663,29 @@ int add_cache_entry(struct cache_entry *ce, int option)
                return -1;
 
        if (!skip_df_check &&
-           check_file_directory_conflict(ce, pos, ok_to_replace)) {
+           check_file_directory_conflict(istate, ce, pos, ok_to_replace)) {
                if (!ok_to_replace)
-                       return error("'%s' appears as both a file and as a directory", ce->name);
-               pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));
+                       return error("'%s' appears as both a file and as a directory",
+                                    ce->name);
+               pos = index_name_pos(istate, ce->name, ntohs(ce->ce_flags));
                pos = -pos-1;
        }
 
        /* Make sure the array is big enough .. */
-       if (active_nr == active_alloc) {
-               active_alloc = alloc_nr(active_alloc);
-               active_cache = xrealloc(active_cache, active_alloc * sizeof(struct cache_entry *));
+       if (istate->cache_nr == istate->cache_alloc) {
+               istate->cache_alloc = alloc_nr(istate->cache_alloc);
+               istate->cache = xrealloc(istate->cache,
+                                       istate->cache_alloc * sizeof(struct cache_entry *));
        }
 
        /* Add it in.. */
-       active_nr++;
-       if (active_nr > pos)
-               memmove(active_cache + pos + 1, active_cache + pos, (active_nr - pos - 1) * sizeof(ce));
-       active_cache[pos] = ce;
-       active_cache_changed = 1;
+       istate->cache_nr++;
+       if (istate->cache_nr > pos)
+               memmove(istate->cache + pos + 1,
+                       istate->cache + pos,
+                       (istate->cache_nr - pos - 1) * sizeof(ce));
+       istate->cache[pos] = ce;
+       istate->cache_changed = 1;
        return 0;
 }
 
@@ -643,18 +700,20 @@ int add_cache_entry(struct cache_entry *ce, int option)
  * For example, you'd want to do this after doing a "git-read-tree",
  * to link up the stat cache details with the proper files.
  */
-struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
+static struct cache_entry *refresh_cache_ent(struct index_state *istate,
+                                            struct cache_entry *ce, int really, int *err)
 {
        struct stat st;
        struct cache_entry *updated;
        int changed, size;
 
        if (lstat(ce->name, &st) < 0) {
-               cache_errno = errno;
+               if (err)
+                       *err = errno;
                return NULL;
        }
 
-       changed = ce_match_stat(ce, &st, really);
+       changed = ie_match_stat(istate, ce, &st, really);
        if (!changed) {
                if (really && assume_unchanged &&
                    !(ce->ce_flags & htons(CE_VALID)))
@@ -663,8 +722,9 @@ struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
                        return ce;
        }
 
-       if (ce_modified(ce, &st, really)) {
-               cache_errno = EINVAL;
+       if (ie_modified(istate, ce, &st, really)) {
+               if (err)
+                       *err = EINVAL;
                return NULL;
        }
 
@@ -685,7 +745,7 @@ struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
        return updated;
 }
 
-int refresh_cache(unsigned int flags)
+int refresh_index(struct index_state *istate, unsigned int flags)
 {
        int i;
        int has_errors = 0;
@@ -694,12 +754,14 @@ int refresh_cache(unsigned int flags)
        int quiet = (flags & REFRESH_QUIET) != 0;
        int not_new = (flags & REFRESH_IGNORE_MISSING) != 0;
 
-       for (i = 0; i < active_nr; i++) {
+       for (i = 0; i < istate->cache_nr; i++) {
                struct cache_entry *ce, *new;
-               ce = active_cache[i];
+               int cache_errno = 0;
+
+               ce = istate->cache[i];
                if (ce_stage(ce)) {
-                       while ((i < active_nr) &&
-                              ! strcmp(active_cache[i]->name, ce->name))
+                       while ((i < istate->cache_nr) &&
+                              ! strcmp(istate->cache[i]->name, ce->name))
                                i++;
                        i--;
                        if (allow_unmerged)
@@ -709,7 +771,7 @@ int refresh_cache(unsigned int flags)
                        continue;
                }
 
-               new = refresh_cache_entry(ce, really);
+               new = refresh_cache_ent(istate, ce, really, &cache_errno);
                if (new == ce)
                        continue;
                if (!new) {
@@ -720,7 +782,7 @@ int refresh_cache(unsigned int flags)
                                 * means the index is not valid anymore.
                                 */
                                ce->ce_flags &= ~htons(CE_VALID);
-                               active_cache_changed = 1;
+                               istate->cache_changed = 1;
                        }
                        if (quiet)
                                continue;
@@ -728,15 +790,20 @@ int refresh_cache(unsigned int flags)
                        has_errors = 1;
                        continue;
                }
-               active_cache_changed = 1;
-               /* You can NOT just free active_cache[i] here, since it
+               istate->cache_changed = 1;
+               /* You can NOT just free istate->cache[i] here, since it
                 * might not be necessarily malloc()ed but can also come
                 * from mmap(). */
-               active_cache[i] = new;
+               istate->cache[i] = new;
        }
        return has_errors;
 }
 
+struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really)
+{
+       return refresh_cache_ent(&the_index, ce, really, NULL);
+}
+
 static int verify_hdr(struct cache_header *hdr, unsigned long size)
 {
        SHA_CTX c;
@@ -754,11 +821,12 @@ static int verify_hdr(struct cache_header *hdr, unsigned long size)
        return 0;
 }
 
-static int read_index_extension(const char *ext, void *data, unsigned long sz)
+static int read_index_extension(struct index_state *istate,
+                               const char *ext, void *data, unsigned long sz)
 {
        switch (CACHE_EXT(ext)) {
        case CACHE_EXT_TREE:
-               active_cache_tree = cache_tree_read(data, sz);
+               istate->cache_tree = cache_tree_read(data, sz);
                break;
        default:
                if (*ext < 'A' || 'Z' < *ext)
@@ -770,13 +838,13 @@ static int read_index_extension(const char *ext, void *data, unsigned long sz)
        return 0;
 }
 
-int read_cache(void)
+int read_index(struct index_state *istate)
 {
-       return read_cache_from(get_index_file());
+       return read_index_from(istate, get_index_file());
 }
 
 /* remember to discard_cache() before reading a different cache! */
-int read_cache_from(const char *path)
+int read_index_from(struct index_state *istate, const char *path)
 {
        int fd, i;
        struct stat st;
@@ -784,11 +852,11 @@ int read_cache_from(const char *path)
        struct cache_header *hdr;
 
        errno = EBUSY;
-       if (cache_mmap)
-               return active_nr;
+       if (istate->mmap)
+               return istate->cache_nr;
 
        errno = ENOENT;
-       index_file_timestamp = 0;
+       istate->timestamp = 0;
        fd = open(path, O_RDONLY);
        if (fd < 0) {
                if (errno == ENOENT)
@@ -796,33 +864,35 @@ int read_cache_from(const char *path)
                die("index file open failed (%s)", strerror(errno));
        }
 
-       if (!fstat(fd, &st)) {
-               cache_mmap_size = xsize_t(st.st_size);
-               errno = EINVAL;
-               if (cache_mmap_size >= sizeof(struct cache_header) + 20)
-                       cache_mmap = xmmap(NULL, cache_mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
-               else
-                       die("index file smaller than expected");
-       } else
+       if (fstat(fd, &st))
                die("cannot stat the open index (%s)", strerror(errno));
+
+       errno = EINVAL;
+       istate->mmap_size = xsize_t(st.st_size);
+       if (istate->mmap_size < sizeof(struct cache_header) + 20)
+               die("index file smaller than expected");
+
+       istate->mmap = xmmap(NULL, istate->mmap_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
        close(fd);
 
-       hdr = cache_mmap;
-       if (verify_hdr(hdr, cache_mmap_size) < 0)
+       hdr = istate->mmap;
+       if (verify_hdr(hdr, istate->mmap_size) < 0)
                goto unmap;
 
-       active_nr = ntohl(hdr->hdr_entries);
-       active_alloc = alloc_nr(active_nr);
-       active_cache = xcalloc(active_alloc, sizeof(struct cache_entry *));
+       istate->cache_nr = ntohl(hdr->hdr_entries);
+       istate->cache_alloc = alloc_nr(istate->cache_nr);
+       istate->cache = xcalloc(istate->cache_alloc, sizeof(struct cache_entry *));
 
        offset = sizeof(*hdr);
-       for (i = 0; i < active_nr; i++) {
-               struct cache_entry *ce = (struct cache_entry *) ((char *) cache_mmap + offset);
+       for (i = 0; i < istate->cache_nr; i++) {
+               struct cache_entry *ce;
+
+               ce = (struct cache_entry *)((char *)(istate->mmap) + offset);
                offset = offset + ce_size(ce);
-               active_cache[i] = ce;
+               istate->cache[i] = ce;
        }
-       index_file_timestamp = st.st_mtime;
-       while (offset <= cache_mmap_size - 20 - 8) {
+       istate->timestamp = st.st_mtime;
+       while (offset <= istate->mmap_size - 20 - 8) {
                /* After an array of active_nr index entries,
                 * there can be arbitrary number of extended
                 * sections, each of which is prefixed with
@@ -830,35 +900,37 @@ int read_cache_from(const char *path)
                 * in 4-byte network byte order.
                 */
                unsigned long extsize;
-               memcpy(&extsize, (char *) cache_mmap + offset + 4, 4);
+               memcpy(&extsize, (char *)(istate->mmap) + offset + 4, 4);
                extsize = ntohl(extsize);
-               if (read_index_extension(((const char *) cache_mmap) + offset,
-                                        (char *) cache_mmap + offset + 8,
+               if (read_index_extension(istate,
+                                        ((const char *) (istate->mmap)) + offset,
+                                        (char *) (istate->mmap) + offset + 8,
                                         extsize) < 0)
                        goto unmap;
                offset += 8;
                offset += extsize;
        }
-       return active_nr;
+       return istate->cache_nr;
 
 unmap:
-       munmap(cache_mmap, cache_mmap_size);
+       munmap(istate->mmap, istate->mmap_size);
        errno = EINVAL;
        die("index file corrupt");
 }
 
-int discard_cache(void)
+int discard_index(struct index_state *istate)
 {
        int ret;
 
-       active_nr = active_cache_changed = 0;
-       index_file_timestamp = 0;
-       cache_tree_free(&active_cache_tree);
-       if (cache_mmap == NULL)
+       istate->cache_nr = 0;
+       istate->cache_changed = 0;
+       istate->timestamp = 0;
+       cache_tree_free(&(istate->cache_tree));
+       if (istate->mmap == NULL)
                return 0;
-       ret = munmap(cache_mmap, cache_mmap_size);
-       cache_mmap = NULL;
-       cache_mmap_size = 0;
+       ret = munmap(istate->mmap, istate->mmap_size);
+       istate->mmap = NULL;
+       istate->mmap_size = 0;
 
        /* no need to throw away allocated active_cache */
        return ret;
@@ -977,11 +1049,13 @@ static void ce_smudge_racily_clean_entry(struct cache_entry *ce)
        }
 }
 
-int write_cache(int newfd, struct cache_entry **cache, int entries)
+int write_index(struct index_state *istate, int newfd)
 {
        SHA_CTX c;
        struct cache_header hdr;
        int i, removed;
+       struct cache_entry **cache = istate->cache;
+       int entries = istate->cache_nr;
 
        for (i = removed = 0; i < entries; i++)
                if (!cache[i]->ce_mode)
@@ -999,17 +1073,17 @@ int write_cache(int newfd, struct cache_entry **cache, int entries)
                struct cache_entry *ce = cache[i];
                if (!ce->ce_mode)
                        continue;
-               if (index_file_timestamp &&
-                   index_file_timestamp <= ntohl(ce->ce_mtime.sec))
+               if (istate->timestamp &&
+                   istate->timestamp <= ntohl(ce->ce_mtime.sec))
                        ce_smudge_racily_clean_entry(ce);
                if (ce_write(&c, newfd, ce, ce_size(ce)) < 0)
                        return -1;
        }
 
        /* Write extension data here */
-       if (active_cache_tree) {
+       if (istate->cache_tree) {
                unsigned long sz;
-               void *data = cache_tree_write(active_cache_tree, &sz);
+               void *data = cache_tree_write(istate->cache_tree, &sz);
                if (data &&
                    !write_index_ext_header(&c, newfd, CACHE_EXT_TREE, sz) &&
                    !ce_write(&c, newfd, data, sz))