Added SDL_GetBasePath() and SDL_GetPrefPath() in new filesystem module.

--HG--
extra : rebase_source : c1fac232063443a2880e64f1abda85e0bdb2e710

src/filesystem/unix/SDL_sysfilesystem.c

@@ -0,0 +1,161 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#ifdef SDL_FILESYSTEM_UNIX
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+/* System dependent filesystem routines                                */
+
+#include <unistd.h>
+
+#include "SDL_error.h"
+#include "SDL_stdinc.h"
+#include "SDL_filesystem.h"
+
+static char *readSymLink(const char *path)
+{
+    char *retval = NULL;
+    ssize_t len = 64;
+    ssize_t rc = -1;
+
+    while (1)
+    {
+        char *ptr = (char *) SDL_realloc(retval, (size_t) len);
+        if (ptr == NULL) {
+            SDL_OutOfMemory();
+            break;
+        }
+
+        retval = ptr;
+
+        rc = readlink(path, retval, len);
+        if (rc == -1) {
+            break;  /* not a symlink, i/o error, etc. */
+        } else if (rc < len) {
+            retval[rc] = '\0';  /* readlink doesn't null-terminate. */
+            return retval;  /* we're good to go. */
+        }
+
+        len *= 2;  /* grow buffer, try again. */
+    }
+
+    if (retval != NULL) {
+        SDL_free(retval);
+    }
+    return NULL;
+}
+
+
+char *
+SDL_GetBasePath(void)
+{
+    char *retval = NULL;
+
+    /* is a Linux-style /proc filesystem available? */
+    if (access("/proc", F_OK) {
+        retval = readSymLink("/proc/self/exe");
+        if (retval == NULL) {
+            /* older kernels don't have /proc/self ... try PID version... */
+            char path[64];
+            const int rc = (int) SDL_snprintf(path, sizeof(path),
+                                              "/proc/%llu/exe",
+                                              (unsigned long long) getpid());
+            if ( (rc > 0) && (rc < sizeof(path)) ) {
+                retval = readSymLink(path);
+            }
+        }
+    }
+
+    /* If we had access to argv[0] here, we could check it for a path,
+        or troll through $PATH looking for it, too. */
+
+    if (retval != NULL) { /* chop off filename. */
+        char *ptr = SDL_strrchr(retval, '/');
+        if (ptr != NULL) {
+            *(ptr+1) = '\0';
+        } else {  /* shouldn't happen, but just in case... */
+            SDL_free(retval);
+            retval = NULL;
+        }
+    }
+
+    if (retval != NULL) {
+        /* try to shrink buffer... */
+        char *ptr = (char *) SDL_realloc(retval, strlen(retval) + 1);
+        if (ptr != NULL)
+            retval = ptr;  /* oh well if it failed. */
+    }
+
+    return retval;
+}
+
+char *
+SDL_GetPrefPath(const char *org, const char *app)
+{
+    /*
+     * We use XDG's base directory spec, even if you're not on Linux.
+     *  This isn't strictly correct, but the results are relatively sane
+     *  in any case.
+     *
+     * http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
+     */
+    const char *envr = SDL_getenv("XDG_DATA_HOME");
+    const char *append = "/";
+    char *retval = NULL;
+    char *ptr = NULL;
+    size_t len = 0;
+
+    if (!envr) {
+        /* You end up with "$HOME/.local/share/Game Name 2" */
+        envr = SDL_getenv("HOME");
+        if (!envr) {
+            /* we could take heroic measures with /etc/passwd, but oh well. */
+            SDL_SetError("neither XDG_DATA_HOME nor HOME environment is set");
+            return NULL;
+        }
+        append = ".local/share/";
+    } /* if */
+
+    len = SDL_strlen(envr) + SDL_strlen(append) + SDL_strlen(app) + 2;
+    retval = (char *) SDL_malloc(len);
+    if (!retval) {
+        SDL_OutOfMemory();
+        return NULL;
+    }
+
+    SDL_snprintf(retval, len, "%s%s%s/", envr, append, app);
+
+    for (ptr = retval+1; *ptr; ptr++) {
+        if (*ptr == '/') {
+            *ptr = '\0';
+            mkdir(retval, 0700);
+            *ptr = '/';
+        }
+    }
+    mkdir(retval, 0700);
+
+    return retval;
+}
+
+#endif /* SDL_FILESYSTEM_UNIX */
+
+/* vi: set ts=4 sw=4 expandtab: */