/*

* Helper functions for tree diff generation

*/

#include "cache.h"

#include "diff.h"

// What paths are we interested in?

static int nr_paths = 0;

static const char **paths = NULL;

static int *pathlens = NULL;

static void update_tree_entry(struct tree_desc *desc)

{

void *buf = desc->buf;

unsigned long size = desc->size;

int len = strlen(buf) + 1 + 20;

if (size < len)

die("corrupt tree file");

desc->buf = buf + len;

desc->size = size - len;

}

static const unsigned char *extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)

{

void *tree = desc->buf;

unsigned long size = desc->size;

int len = strlen(tree)+1;

const unsigned char *sha1 = tree + len;

const char *path = strchr(tree, ' ');

unsigned int mode;

if (!path || size < len + 20 || sscanf(tree, "%o", &mode) != 1)

die("corrupt tree file");

*pathp = path+1;

*modep = DIFF_FILE_CANON_MODE(mode);

return sha1;

}

static char *malloc_base(const char *base, const char *path, int pathlen)

{

int baselen = strlen(base);

char *newbase = xmalloc(baselen + pathlen + 2);

memcpy(newbase, base, baselen);

memcpy(newbase + baselen, path, pathlen);

memcpy(newbase + baselen + pathlen, "/", 2);

return newbase;

}

static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base);

static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)

{

unsigned mode1, mode2;

const char *path1, *path2;

const unsigned char *sha1, *sha2;

int cmp, pathlen1, pathlen2;

sha1 = extract(t1, &path1, &mode1);

sha2 = extract(t2, &path2, &mode2);

pathlen1 = strlen(path1);

pathlen2 = strlen(path2);

cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);

if (cmp < 0) {

show_entry(opt, "-", t1, base);

return -1;

}

if (cmp > 0) {

show_entry(opt, "+", t2, base);

return 1;

}

if (!opt->find_copies_harder &&

!memcmp(sha1, sha2, 20) && mode1 == mode2)

return 0;

/*

* If the filemode has changed to/from a directory from/to a regular

* file, we need to consider it a remove and an add.

*/

if (S_ISDIR(mode1) != S_ISDIR(mode2)) {

show_entry(opt, "-", t1, base);

show_entry(opt, "+", t2, base);

return 0;

}

if (opt->recursive && S_ISDIR(mode1)) {

int retval;

char *newbase = malloc_base(base, path1, pathlen1);

if (opt->tree_in_recursive)

opt->change(opt, mode1, mode2,

sha1, sha2, base, path1);

retval = diff_tree_sha1(sha1, sha2, newbase, opt);

free(newbase);

return retval;

}

opt->change(opt, mode1, mode2, sha1, sha2, base, path1);

return 0;

}

static int interesting(struct tree_desc *desc, const char *base)

{

const char *path;

unsigned mode;

int i;

int baselen, pathlen;

if (!nr_paths)

return 1;

(void)extract(desc, &path, &mode);

pathlen = strlen(path);

baselen = strlen(base);

for (i=0; i < nr_paths; i++) {

const char *match = paths[i];

int matchlen = pathlens[i];

if (baselen >= matchlen) {

/* If it doesn't match, move along... */

if (strncmp(base, match, matchlen))

continue;

/* The base is a subdirectory of a path which was specified. */

return 1;

}

/* Does the base match? */

if (strncmp(base, match, baselen))

continue;

match += baselen;

matchlen -= baselen;

if (pathlen > matchlen)

continue;

if (matchlen > pathlen) {

if (match[pathlen] != '/')

continue;

if (!S_ISDIR(mode))

continue;

}

if (strncmp(path, match, pathlen))

continue;

return 1;

}

return 0; /* No matches */

}

/* A whole sub-tree went away or appeared */

static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)

{

while (desc->size) {

if (interesting(desc, base))

show_entry(opt, prefix, desc, base);

update_tree_entry(desc);

}

}

/* A file entry went away or appeared */

static int show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)

{

unsigned mode;

const char *path;

const unsigned char *sha1 = extract(desc, &path, &mode);

if (opt->recursive && S_ISDIR(mode)) {

char type[20];

char *newbase = malloc_base(base, path, strlen(path));

struct tree_desc inner;

void *tree;

tree = read_sha1_file(sha1, type, &inner.size);

if (!tree || strcmp(type, "tree"))

die("corrupt tree sha %s", sha1_to_hex(sha1));

inner.buf = tree;

show_tree(opt, prefix, &inner, newbase);

free(tree);

free(newbase);

return 0;

}

opt->add_remove(opt, prefix[0], mode, sha1, base, path);

return 0;

}

int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)

{

while (t1->size | t2->size) {

if (nr_paths && t1->size && !interesting(t1, base)) {

update_tree_entry(t1);

continue;

}

if (nr_paths && t2->size && !interesting(t2, base)) {

update_tree_entry(t2);

continue;

}

if (!t1->size) {

show_entry(opt, "+", t2, base);

update_tree_entry(t2);

continue;

}

if (!t2->size) {

show_entry(opt, "-", t1, base);

update_tree_entry(t1);

continue;

}

switch (compare_tree_entry(t1, t2, base, opt)) {

case -1:

update_tree_entry(t1);

continue;

case 0:

update_tree_entry(t1);

/* Fallthrough */

case 1:

update_tree_entry(t2);

continue;

}

die("git-diff-tree: internal error");

}

return 0;

}

int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)

{

void *tree1, *tree2;

struct tree_desc t1, t2;

int retval;

tree1 = read_object_with_reference(old, "tree", &t1.size, NULL);

if (!tree1)

die("unable to read source tree (%s)", sha1_to_hex(old));

tree2 = read_object_with_reference(new, "tree", &t2.size, NULL);

if (!tree2)

die("unable to read destination tree (%s)", sha1_to_hex(new));

t1.buf = tree1;

t2.buf = tree2;

retval = diff_tree(&t1, &t2, base, opt);

free(tree1);

free(tree2);

return retval;

}

static int count_paths(const char **paths)

{

int i = 0;

while (*paths++)

i++;

return i;

}

void diff_tree_setup_paths(const char **p)

{

if (p) {

int i;

paths = p;

nr_paths = count_paths(paths);

pathlens = xmalloc(nr_paths * sizeof(int));

for (i=0; i<nr_paths; i++)

pathlens[i] = strlen(paths[i]);

}

}