From f279242d5e3f17e01e1d70010c4f072798899a47 Mon Sep 17 00:00:00 2001 From: Karsten Blees Date: Thu, 17 Jul 2014 17:38:02 +0200 Subject: Win32: reduce environment array reallocations 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 Signed-off-by: Stepan Kasal Signed-off-by: Junio C Hamano --- compat/mingw.c | 62 +++++++++++++++++++++++++++++++++------------------------- 1 file changed, 35 insertions(+), 27 deletions(-) diff --git a/compat/mingw.c b/compat/mingw.c index 789a0ec6dc..967c1a0a58 100644 --- a/compat/mingw.c +++ b/compat/mingw.c @@ -899,7 +899,12 @@ static char *path_lookup(const char *cmd, char **path, int exe_only) 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) { @@ -915,31 +920,28 @@ static int compareenv(const void *a, const void *b) static wchar_t *make_environment_block(char **deltaenv) { wchar_t *wenvblk = NULL; - int count = 0; - char **e, **tmpenv; - int size = 0, wenvsz = 0, wenvpos = 0; + char **tmpenv; + int i = 0, size = environ_size, wenvsz = 0, wenvpos = 0; - while (environ[count]) - count++; + while (deltaenv && deltaenv[i]) + i++; - /* copy the environment */ - tmpenv = xmalloc(sizeof(*tmpenv) * (count + 1)); - memcpy(tmpenv, environ, sizeof(*tmpenv) * (count + 1)); + /* copy the environment, leaving space for changes */ + tmpenv = xmalloc((size + i) * sizeof(char*)); + memcpy(tmpenv, environ, size * sizeof(char*)); /* merge supplied environment changes into the temporary environment */ - for (e = deltaenv; e && *e; e++) - tmpenv = do_putenv(tmpenv, *e, 0); + for (i = 0; deltaenv && deltaenv[i]; i++) + size = do_putenv(tmpenv, deltaenv[i], size, 0); /* environment must be sorted */ - for (count = 0; tmpenv[count]; ) - count++; - qsort(tmpenv, count, sizeof(*tmpenv), compareenv); + qsort(tmpenv, size - 1, sizeof(char*), compareenv); /* create environment block from temporary environment */ - for (e = tmpenv; *e; e++) { - size = 2 * strlen(*e) + 2; /* +2 for final \0 */ + for (i = 0; tmpenv[i]; i++) { + size = 2 * strlen(tmpenv[i]) + 2; /* +2 for final \0 */ 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 */ 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 + * 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, '='); int i = lookupenv(env, name, eq-name); if (i < 0) { if (*eq) { - for (i = 0; env[i]; i++) - ; - env = xrealloc(env, (i+2)*sizeof(*env)); - env[i] = (char*) name; - env[i+1] = NULL; + env[size - 1] = (char*) name; + env[size] = NULL; + size++; } } else { @@ -1226,11 +1228,13 @@ static char **do_putenv(char **env, const char *name, int free_old) free(env[i]); if (*eq) env[i] = (char*) name; - else + else { for (; env[i]; i++) env[i] = env[i+1]; + size--; + } } - return env; + return size; } #undef getenv @@ -1248,7 +1252,8 @@ char *mingw_getenv(const char *name) 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; } @@ -2048,7 +2053,9 @@ void mingw_startup() maxlen = max(maxlen, wcslen(wenv[i])); /* 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) */ maxlen = 3 * maxlen + 1; @@ -2065,6 +2072,7 @@ void mingw_startup() len = xwcstoutf(buffer, wenv[i], maxlen); environ[i] = xmemdupz(buffer, len); } + environ[i] = NULL; free(buffer); /* initialize critical section for waitpid pinfo_t list */ -- cgit v1.2.3