mirror/git
1
0
Fork 0
mirror of https://github.com/git/git.git synced 2024-09-28 10:00:54 +02:00
Code

Win32: reduce environment array reallocations

Browse Source 
Move environment array reallocation from do_putenv to the respective
callers. Keep track of the environment size in a global variable. Use
ALLOC_GROW in mingw_putenv to reduce reallocations. Allocate a
sufficiently sized environment array in make_environment_block to prevent
reallocations.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Stepan Kasal <kasal@ucw.cz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Karsten Blees 2014-07-17 17:38:02 +02:00 committed by Junio C Hamano
parent 77734da241
commit f279242d5e
1 changed files with 35 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
compat/mingw.c
View File

@ -899,7 +899,12 @@ static char *path_lookup(const char *cmd, char **path, int exe_only)
return prog; return prog;
} }
static char **do_putenv(char **env, const char *name, int free_old); static int do_putenv(char **env, const char *name, int size, int free_old);
/* used number of elements of environ array, including terminating NULL */
static int environ_size = 0;
/* allocated size of environ array, in bytes */
static int environ_alloc = 0;
static int compareenv(const void *a, const void *b) static int compareenv(const void *a, const void *b)
{ {
@ -915,31 +920,28 @@ static int compareenv(const void *a, const void *b)
static wchar_t *make_environment_block(char **deltaenv) static wchar_t *make_environment_block(char **deltaenv)
{ {
wchar_t *wenvblk = NULL; wchar_t *wenvblk = NULL;
int count = 0; char **tmpenv;
char **e, **tmpenv; int i = 0, size = environ_size, wenvsz = 0, wenvpos = 0;
int size = 0, wenvsz = 0, wenvpos = 0;
while (environ[count]) while (deltaenv && deltaenv[i])
count++; i++;
/* copy the environment */ /* copy the environment, leaving space for changes */
tmpenv = xmalloc(sizeof(*tmpenv) * (count + 1)); tmpenv = xmalloc((size + i) * sizeof(char*));
memcpy(tmpenv, environ, sizeof(*tmpenv) * (count + 1)); memcpy(tmpenv, environ, size * sizeof(char*));
/* merge supplied environment changes into the temporary environment */ /* merge supplied environment changes into the temporary environment */
for (e = deltaenv; e && *e; e++) for (i = 0; deltaenv && deltaenv[i]; i++)
tmpenv = do_putenv(tmpenv, *e, 0); size = do_putenv(tmpenv, deltaenv[i], size, 0);
/* environment must be sorted */ /* environment must be sorted */
for (count = 0; tmpenv[count]; ) qsort(tmpenv, size - 1, sizeof(char*), compareenv);
count++;
qsort(tmpenv, count, sizeof(*tmpenv), compareenv);
/* create environment block from temporary environment */ /* create environment block from temporary environment */
for (e = tmpenv; *e; e++) { for (i = 0; tmpenv[i]; i++) {
size = 2 * strlen(*e) + 2; /* +2 for final \0 */ size = 2 * strlen(tmpenv[i]) + 2; /* +2 for final \0 */
ALLOC_GROW(wenvblk, (wenvpos + size) * sizeof(wchar_t), wenvsz); ALLOC_GROW(wenvblk, (wenvpos + size) * sizeof(wchar_t), wenvsz);
wenvpos += xutftowcs(&wenvblk[wenvpos], *e, size) + 1; wenvpos += xutftowcs(&wenvblk[wenvpos], tmpenv[i], size) + 1;
} }
/* add final \0 terminator */ /* add final \0 terminator */
wenvblk[wenvpos] = 0; wenvblk[wenvpos] = 0;
@ -1206,19 +1208,19 @@ static int lookupenv(char **env, const char *name, size_t nmln)
/* /*
* If name contains '=', then sets the variable, otherwise it unsets it * If name contains '=', then sets the variable, otherwise it unsets it
* Size includes the terminating NULL. Env must have room for size + 1 entries
* (in case of insert). Returns the new size. Optionally frees removed entries.
*/ */
static char **do_putenv(char **env, const char *name, int free_old) static int do_putenv(char **env, const char *name, int size, int free_old)
{ {
char *eq = strchrnul(name, '='); char *eq = strchrnul(name, '=');
int i = lookupenv(env, name, eq-name); int i = lookupenv(env, name, eq-name);
if (i < 0) { if (i < 0) {
if (*eq) { if (*eq) {
for (i = 0; env[i]; i++) env[size - 1] = (char*) name;
; env[size] = NULL;
env = xrealloc(env, (i+2)*sizeof(*env)); size++;
env[i] = (char*) name;
env[i+1] = NULL;
} }
} }
else { else {
@ -1226,11 +1228,13 @@ static char **do_putenv(char **env, const char *name, int free_old)
free(env[i]); free(env[i]);
if (*eq) if (*eq)
env[i] = (char*) name; env[i] = (char*) name;
else else {
for (; env[i]; i++) for (; env[i]; i++)
env[i] = env[i+1]; env[i] = env[i+1];
size--;
}
} }
return env; return size;
} }
#undef getenv #undef getenv
@ -1248,7 +1252,8 @@ char *mingw_getenv(const char *name)
int mingw_putenv(const char *namevalue) int mingw_putenv(const char *namevalue)
{ {
environ = do_putenv(environ, namevalue, 1); ALLOC_GROW(environ, (environ_size + 1) * sizeof(char*), environ_alloc);
environ_size = do_putenv(environ, namevalue, environ_size, 1);
return 0; return 0;
} }
@ -2048,7 +2053,9 @@ void mingw_startup()
maxlen = max(maxlen, wcslen(wenv[i])); maxlen = max(maxlen, wcslen(wenv[i]));
/* nedmalloc can't free CRT memory, allocate resizable environment list */ /* nedmalloc can't free CRT memory, allocate resizable environment list */
environ = xcalloc(i + 1, sizeof(char*)); environ = NULL;
environ_size = i + 1;
ALLOC_GROW(environ, environ_size * sizeof(char*), environ_alloc);
/* allocate buffer (wchar_t encodes to max 3 UTF-8 bytes) */ /* allocate buffer (wchar_t encodes to max 3 UTF-8 bytes) */
maxlen = 3 * maxlen + 1; maxlen = 3 * maxlen + 1;
@ -2065,6 +2072,7 @@ void mingw_startup()
len = xwcstoutf(buffer, wenv[i], maxlen); len = xwcstoutf(buffer, wenv[i], maxlen);
environ[i] = xmemdupz(buffer, len); environ[i] = xmemdupz(buffer, len);
} }
environ[i] = NULL;
free(buffer); free(buffer);
/* initialize critical section for waitpid pinfo_t list */ /* initialize critical section for waitpid pinfo_t list */