Merge branch 'ab/test-must-be-empty-for-master'
[gitweb.git] / read-cache.c
index e865254bea028485e1731d316727b66753a8fc5e..c5fabc844aad68f60a30d0ff7498ff7e5d692a7a 100644 (file)
@@ -6,6 +6,8 @@
 #define NO_THE_INDEX_COMPATIBILITY_MACROS
 #include "cache.h"
 #include "config.h"
+#include "diff.h"
+#include "diffcore.h"
 #include "tempfile.h"
 #include "lockfile.h"
 #include "cache-tree.h"
                 CE_ENTRY_ADDED | CE_ENTRY_REMOVED | CE_ENTRY_CHANGED | \
                 SPLIT_INDEX_ORDERED | UNTRACKED_CHANGED | FSMONITOR_CHANGED)
 
+
+/*
+ * This is an estimate of the pathname length in the index.  We use
+ * this for V4 index files to guess the un-deltafied size of the index
+ * in memory because of pathname deltafication.  This is not required
+ * for V2/V3 index formats because their pathnames are not compressed.
+ * If the initial amount of memory set aside is not sufficient, the
+ * mem pool will allocate extra memory.
+ */
+#define CACHE_ENTRY_PATH_LENGTH 80
+
+static inline struct cache_entry *mem_pool__ce_alloc(struct mem_pool *mem_pool, size_t len)
+{
+       struct cache_entry *ce;
+       ce = mem_pool_alloc(mem_pool, cache_entry_size(len));
+       ce->mem_pool_allocated = 1;
+       return ce;
+}
+
+static inline struct cache_entry *mem_pool__ce_calloc(struct mem_pool *mem_pool, size_t len)
+{
+       struct cache_entry * ce;
+       ce = mem_pool_calloc(mem_pool, 1, cache_entry_size(len));
+       ce->mem_pool_allocated = 1;
+       return ce;
+}
+
+static struct mem_pool *find_mem_pool(struct index_state *istate)
+{
+       struct mem_pool **pool_ptr;
+
+       if (istate->split_index && istate->split_index->base)
+               pool_ptr = &istate->split_index->base->ce_mem_pool;
+       else
+               pool_ptr = &istate->ce_mem_pool;
+
+       if (!*pool_ptr)
+               mem_pool_init(pool_ptr, 0);
+
+       return *pool_ptr;
+}
+
 struct index_state the_index;
 static const char *alternate_index_output;
 
@@ -62,7 +106,7 @@ static void replace_index_entry(struct index_state *istate, int nr, struct cache
 
        replace_index_entry_in_base(istate, old, ce);
        remove_name_hash(istate, old);
-       free(old);
+       discard_cache_entry(old);
        ce->ce_flags &= ~CE_HASHED;
        set_index_entry(istate, nr, ce);
        ce->ce_flags |= CE_UPDATE_IN_BASE;
@@ -75,7 +119,7 @@ void rename_index_entry_at(struct index_state *istate, int nr, const char *new_n
        struct cache_entry *old_entry = istate->cache[nr], *new_entry;
        int namelen = strlen(new_name);
 
-       new_entry = xmalloc(cache_entry_size(namelen));
+       new_entry = make_empty_cache_entry(istate, namelen);
        copy_cache_entry(new_entry, old_entry);
        new_entry->ce_flags &= ~CE_HASHED;
        new_entry->ce_namelen = namelen;
@@ -624,7 +668,7 @@ static struct cache_entry *create_alias_ce(struct index_state *istate,
 
        /* Ok, create the new entry using the name of the existing alias */
        len = ce_namelen(alias);
-       new_entry = xcalloc(1, cache_entry_size(len));
+       new_entry = make_empty_cache_entry(istate, len);
        memcpy(new_entry->name, alias->name, len);
        copy_cache_entry(new_entry, ce);
        save_or_free_index_entry(istate, ce);
@@ -641,7 +685,7 @@ void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
 
 int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags)
 {
-       int size, namelen, was_same;
+       int namelen, was_same;
        mode_t st_mode = st->st_mode;
        struct cache_entry *ce, *alias = NULL;
        unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE|CE_MATCH_RACY_IS_DIRTY;
@@ -663,8 +707,7 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
                while (namelen && path[namelen-1] == '/')
                        namelen--;
        }
-       size = cache_entry_size(namelen);
-       ce = xcalloc(1, size);
+       ce = make_empty_cache_entry(istate, namelen);
        memcpy(ce->name, path, namelen);
        ce->ce_namelen = namelen;
        if (!intent_only)
@@ -705,13 +748,13 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
                                ce_mark_uptodate(alias);
                        alias->ce_flags |= CE_ADDED;
 
-                       free(ce);
+                       discard_cache_entry(ce);
                        return 0;
                }
        }
        if (!intent_only) {
                if (index_path(&ce->oid, path, st, newflags)) {
-                       free(ce);
+                       discard_cache_entry(ce);
                        return error("unable to index file %s", path);
                }
        } else
@@ -728,9 +771,9 @@ int add_to_index(struct index_state *istate, const char *path, struct stat *st,
                    ce->ce_mode == alias->ce_mode);
 
        if (pretend)
-               free(ce);
+               discard_cache_entry(ce);
        else if (add_index_entry(istate, ce, add_option)) {
-               free(ce);
+               discard_cache_entry(ce);
                return error("unable to add %s to index", path);
        }
        if (verbose && !was_same)
@@ -746,12 +789,25 @@ int add_file_to_index(struct index_state *istate, const char *path, int flags)
        return add_to_index(istate, path, &st, flags);
 }
 
-struct cache_entry *make_cache_entry(unsigned int mode,
-               const unsigned char *sha1, const char *path, int stage,
-               unsigned int refresh_options)
+struct cache_entry *make_empty_cache_entry(struct index_state *istate, size_t len)
+{
+       return mem_pool__ce_calloc(find_mem_pool(istate), len);
+}
+
+struct cache_entry *make_empty_transient_cache_entry(size_t len)
+{
+       return xcalloc(1, cache_entry_size(len));
+}
+
+struct cache_entry *make_cache_entry(struct index_state *istate,
+                                    unsigned int mode,
+                                    const struct object_id *oid,
+                                    const char *path,
+                                    int stage,
+                                    unsigned int refresh_options)
 {
-       int size, len;
        struct cache_entry *ce, *ret;
+       int len;
 
        if (!verify_path(path, mode)) {
                error("Invalid path '%s'", path);
@@ -759,21 +815,43 @@ struct cache_entry *make_cache_entry(unsigned int mode,
        }
 
        len = strlen(path);
-       size = cache_entry_size(len);
-       ce = xcalloc(1, size);
+       ce = make_empty_cache_entry(istate, len);
 
-       hashcpy(ce->oid.hash, sha1);
+       oidcpy(&ce->oid, oid);
        memcpy(ce->name, path, len);
        ce->ce_flags = create_ce_flags(stage);
        ce->ce_namelen = len;
        ce->ce_mode = create_ce_mode(mode);
 
-       ret = refresh_cache_entry(ce, refresh_options);
+       ret = refresh_cache_entry(&the_index, ce, refresh_options);
        if (ret != ce)
-               free(ce);
+               discard_cache_entry(ce);
        return ret;
 }
 
+struct cache_entry *make_transient_cache_entry(unsigned int mode, const struct object_id *oid,
+                                              const char *path, int stage)
+{
+       struct cache_entry *ce;
+       int len;
+
+       if (!verify_path(path, mode)) {
+               error("Invalid path '%s'", path);
+               return NULL;
+       }
+
+       len = strlen(path);
+       ce = make_empty_transient_cache_entry(len);
+
+       oidcpy(&ce->oid, oid);
+       memcpy(ce->name, path, len);
+       ce->ce_flags = create_ce_flags(stage);
+       ce->ce_namelen = len;
+       ce->ce_mode = create_ce_mode(mode);
+
+       return ce;
+}
+
 /*
  * Chmod an index entry with either +x or -x.
  *
@@ -1269,7 +1347,7 @@ static struct cache_entry *refresh_cache_ent(struct index_state *istate,
 {
        struct stat st;
        struct cache_entry *updated;
-       int changed, size;
+       int changed;
        int refresh = options & CE_MATCH_REFRESH;
        int ignore_valid = options & CE_MATCH_IGNORE_VALID;
        int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE;
@@ -1349,8 +1427,7 @@ static struct cache_entry *refresh_cache_ent(struct index_state *istate,
                return NULL;
        }
 
-       size = ce_size(ce);
-       updated = xmalloc(size);
+       updated = make_empty_cache_entry(istate, ce_namelen(ce));
        copy_cache_entry(updated, ce);
        memcpy(updated->name, ce->name, ce->ce_namelen + 1);
        fill_stat_cache_info(updated, &st);
@@ -1474,10 +1551,11 @@ int refresh_index(struct index_state *istate, unsigned int flags,
        return has_errors;
 }
 
-struct cache_entry *refresh_cache_entry(struct cache_entry *ce,
-                                              unsigned int options)
+struct cache_entry *refresh_cache_entry(struct index_state *istate,
+                                       struct cache_entry *ce,
+                                       unsigned int options)
 {
-       return refresh_cache_ent(&the_index, ce, options, NULL, NULL);
+       return refresh_cache_ent(istate, ce, options, NULL, NULL);
 }
 
 
@@ -1635,12 +1713,13 @@ int read_index(struct index_state *istate)
        return read_index_from(istate, get_index_file(), get_git_dir());
 }
 
-static struct cache_entry *cache_entry_from_ondisk(struct ondisk_cache_entry *ondisk,
+static struct cache_entry *cache_entry_from_ondisk(struct mem_pool *mem_pool,
+                                                  struct ondisk_cache_entry *ondisk,
                                                   unsigned int flags,
                                                   const char *name,
                                                   size_t len)
 {
-       struct cache_entry *ce = xmalloc(cache_entry_size(len));
+       struct cache_entry *ce = mem_pool__ce_alloc(mem_pool, len);
 
        ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec);
        ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec);
@@ -1682,7 +1761,8 @@ static unsigned long expand_name_field(struct strbuf *name, const char *cp_)
        return (const char *)ep + 1 - cp_;
 }
 
-static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
+static struct cache_entry *create_from_disk(struct mem_pool *mem_pool,
+                                           struct ondisk_cache_entry *ondisk,
                                            unsigned long *ent_size,
                                            struct strbuf *previous_name)
 {
@@ -1713,13 +1793,13 @@ static struct cache_entry *create_from_disk(struct ondisk_cache_entry *ondisk,
                /* v3 and earlier */
                if (len == CE_NAMEMASK)
                        len = strlen(name);
-               ce = cache_entry_from_ondisk(ondisk, flags, name, len);
+               ce = cache_entry_from_ondisk(mem_pool, ondisk, flags, name, len);
 
                *ent_size = ondisk_ce_size(ce);
        } else {
                unsigned long consumed;
                consumed = expand_name_field(previous_name, name);
-               ce = cache_entry_from_ondisk(ondisk, flags,
+               ce = cache_entry_from_ondisk(mem_pool, ondisk, flags,
                                             previous_name->buf,
                                             previous_name->len);
 
@@ -1793,6 +1873,22 @@ static void post_read_index_from(struct index_state *istate)
        tweak_fsmonitor(istate);
 }
 
+static size_t estimate_cache_size_from_compressed(unsigned int entries)
+{
+       return entries * (sizeof(struct cache_entry) + CACHE_ENTRY_PATH_LENGTH);
+}
+
+static size_t estimate_cache_size(size_t ondisk_size, unsigned int entries)
+{
+       long per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry);
+
+       /*
+        * Account for potential alignment differences.
+        */
+       per_entry += align_padding_size(sizeof(struct cache_entry), -sizeof(struct ondisk_cache_entry));
+       return ondisk_size + entries * per_entry;
+}
+
 /* remember to discard_cache() before reading a different cache! */
 int do_read_index(struct index_state *istate, const char *path, int must_exist)
 {
@@ -1839,10 +1935,15 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
        istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache));
        istate->initialized = 1;
 
-       if (istate->version == 4)
+       if (istate->version == 4) {
                previous_name = &previous_name_buf;
-       else
+               mem_pool_init(&istate->ce_mem_pool,
+                             estimate_cache_size_from_compressed(istate->cache_nr));
+       } else {
                previous_name = NULL;
+               mem_pool_init(&istate->ce_mem_pool,
+                             estimate_cache_size(mmap_size, istate->cache_nr));
+       }
 
        src_offset = sizeof(*hdr);
        for (i = 0; i < istate->cache_nr; i++) {
@@ -1851,7 +1952,7 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
                unsigned long consumed;
 
                disk_ce = (struct ondisk_cache_entry *)((char *)mmap + src_offset);
-               ce = create_from_disk(disk_ce, &consumed, previous_name);
+               ce = create_from_disk(istate->ce_mem_pool, disk_ce, &consumed, previous_name);
                set_index_entry(istate, i, ce);
 
                src_offset += consumed;
@@ -1948,17 +2049,15 @@ int is_index_unborn(struct index_state *istate)
 
 int discard_index(struct index_state *istate)
 {
-       int i;
+       /*
+        * Cache entries in istate->cache[] should have been allocated
+        * from the memory pool associated with this index, or from an
+        * associated split_index. There is no need to free individual
+        * cache entries. validate_cache_entries can detect when this
+        * assertion does not hold.
+        */
+       validate_cache_entries(istate);
 
-       for (i = 0; i < istate->cache_nr; i++) {
-               if (istate->cache[i]->index &&
-                   istate->split_index &&
-                   istate->split_index->base &&
-                   istate->cache[i]->index <= istate->split_index->base->cache_nr &&
-                   istate->cache[i] == istate->split_index->base->cache[istate->cache[i]->index - 1])
-                       continue;
-               free(istate->cache[i]);
-       }
        resolve_undo_clear_index(istate);
        istate->cache_nr = 0;
        istate->cache_changed = 0;
@@ -1972,9 +2071,47 @@ int discard_index(struct index_state *istate)
        discard_split_index(istate);
        free_untracked_cache(istate->untracked);
        istate->untracked = NULL;
+
+       if (istate->ce_mem_pool) {
+               mem_pool_discard(istate->ce_mem_pool, should_validate_cache_entries());
+               istate->ce_mem_pool = NULL;
+       }
+
        return 0;
 }
 
+/*
+ * Validate the cache entries of this index.
+ * All cache entries associated with this index
+ * should have been allocated by the memory pool
+ * associated with this index, or by a referenced
+ * split index.
+ */
+void validate_cache_entries(const struct index_state *istate)
+{
+       int i;
+
+       if (!should_validate_cache_entries() ||!istate || !istate->initialized)
+               return;
+
+       for (i = 0; i < istate->cache_nr; i++) {
+               if (!istate) {
+                       die("internal error: cache entry is not allocated from expected memory pool");
+               } else if (!istate->ce_mem_pool ||
+                       !mem_pool_contains(istate->ce_mem_pool, istate->cache[i])) {
+                       if (!istate->split_index ||
+                               !istate->split_index->base ||
+                               !istate->split_index->base->ce_mem_pool ||
+                               !mem_pool_contains(istate->split_index->base->ce_mem_pool, istate->cache[i])) {
+                               die("internal error: cache entry is not allocated from expected memory pool");
+                       }
+               }
+       }
+
+       if (istate->split_index)
+               validate_cache_entries(istate->split_index->base);
+}
+
 int unmerged_index(const struct index_state *istate)
 {
        int i;
@@ -1985,6 +2122,44 @@ int unmerged_index(const struct index_state *istate)
        return 0;
 }
 
+int index_has_changes(const struct index_state *istate,
+                     struct tree *tree,
+                     struct strbuf *sb)
+{
+       struct object_id cmp;
+       int i;
+
+       if (istate != &the_index) {
+               BUG("index_has_changes cannot yet accept istate != &the_index; do_diff_cache needs updating first.");
+       }
+       if (tree)
+               cmp = tree->object.oid;
+       if (tree || !get_oid_tree("HEAD", &cmp)) {
+               struct diff_options opt;
+
+               diff_setup(&opt);
+               opt.flags.exit_with_status = 1;
+               if (!sb)
+                       opt.flags.quick = 1;
+               do_diff_cache(&cmp, &opt);
+               diffcore_std(&opt);
+               for (i = 0; sb && i < diff_queued_diff.nr; i++) {
+                       if (i)
+                               strbuf_addch(sb, ' ');
+                       strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
+               }
+               diff_flush(&opt);
+               return opt.flags.has_changes != 0;
+       } else {
+               for (i = 0; sb && i < istate->cache_nr; i++) {
+                       if (i)
+                               strbuf_addch(sb, ' ');
+                       strbuf_addstr(sb, istate->cache[i]->name);
+               }
+               return !!istate->cache_nr;
+       }
+}
+
 #define WRITE_BUFFER_SIZE 8192
 static unsigned char write_buffer[WRITE_BUFFER_SIZE];
 static unsigned long write_buffer_len;
@@ -2633,10 +2808,13 @@ int write_locked_index(struct index_state *istate, struct lock_file *lock,
 
 /*
  * Read the index file that is potentially unmerged into given
- * index_state, dropping any unmerged entries.  Returns true if
- * the index is unmerged.  Callers who want to refuse to work
- * from an unmerged state can call this and check its return value,
- * instead of calling read_cache().
+ * index_state, dropping any unmerged entries to stage #0 (potentially
+ * resulting in a path appearing as both a file and a directory in the
+ * index; the caller is responsible to clear out the extra entries
+ * before writing the index to a tree).  Returns true if the index is
+ * unmerged.  Callers who want to refuse to work from an unmerged
+ * state can call this and check its return value, instead of calling
+ * read_cache().
  */
 int read_index_unmerged(struct index_state *istate)
 {
@@ -2647,19 +2825,18 @@ int read_index_unmerged(struct index_state *istate)
        for (i = 0; i < istate->cache_nr; i++) {
                struct cache_entry *ce = istate->cache[i];
                struct cache_entry *new_ce;
-               int size, len;
+               int len;
 
                if (!ce_stage(ce))
                        continue;
                unmerged = 1;
                len = ce_namelen(ce);
-               size = cache_entry_size(len);
-               new_ce = xcalloc(1, size);
+               new_ce = make_empty_cache_entry(istate, len);
                memcpy(new_ce->name, ce->name, len);
                new_ce->ce_flags = create_ce_flags(0) | CE_CONFLICTED;
                new_ce->ce_namelen = len;
                new_ce->ce_mode = ce->ce_mode;
-               if (add_index_entry(istate, new_ce, 0))
+               if (add_index_entry(istate, new_ce, ADD_CACHE_SKIP_DFCHECK))
                        return error("%s: cannot drop to stage #0",
                                     new_ce->name);
        }
@@ -2763,3 +2940,41 @@ void move_index_extensions(struct index_state *dst, struct index_state *src)
        dst->untracked = src->untracked;
        src->untracked = NULL;
 }
+
+struct cache_entry *dup_cache_entry(const struct cache_entry *ce,
+                                   struct index_state *istate)
+{
+       unsigned int size = ce_size(ce);
+       int mem_pool_allocated;
+       struct cache_entry *new_entry = make_empty_cache_entry(istate, ce_namelen(ce));
+       mem_pool_allocated = new_entry->mem_pool_allocated;
+
+       memcpy(new_entry, ce, size);
+       new_entry->mem_pool_allocated = mem_pool_allocated;
+       return new_entry;
+}
+
+void discard_cache_entry(struct cache_entry *ce)
+{
+       if (ce && should_validate_cache_entries())
+               memset(ce, 0xCD, cache_entry_size(ce->ce_namelen));
+
+       if (ce && ce->mem_pool_allocated)
+               return;
+
+       free(ce);
+}
+
+int should_validate_cache_entries(void)
+{
+       static int validate_index_cache_entries = -1;
+
+       if (validate_index_cache_entries < 0) {
+               if (getenv("GIT_TEST_VALIDATE_INDEX_CACHE_ENTRIES"))
+                       validate_index_cache_entries = 1;
+               else
+                       validate_index_cache_entries = 0;
+       }
+
+       return validate_index_cache_entries;
+}