New platform API for storage methods.

This includes converting the ZeroTier transport to use these.

The new API supports file creation, retrieval, and deletion. It
also supports directory methods for traversal, creation, and
deletion.  It also has a few methods to obtain well-known directories
like $TMPDIR and $HOME.

A rich test suite for this functionality is added as well.

1 files changed, 47 insertions, 3 deletions

diff --git a/src/core/platform.h b/src/core/platform.h
index 10074677..8b709e93 100644
--- a/src/core/platform.h
+++ b/src/core/platform.h
@@ -368,21 +368,65 @@ extern void nni_plat_pipe_close(int, int);
 // determined by using an environment variable (NNG_STATE_DIR), or
 // using some other application-specific method.
 //
+// We also support listing keys, for the case where a key must be looked
+// up -- for example to get a list of certificates, or some such.
+//
 
 // nni_plat_file_put writes the named file, with the provided data,
 // and the given size.  If the file already exists it is overwritten.
 // The permissions on the file should be limited to read and write
 // access by the entity running the application only.
-extern int nni_plat_file_put(const char *, const void *, int);
+extern int nni_plat_file_put(const char *, const void *, size_t);
 
 // nni_plat_file_get reads the entire named file, allocating storage
 // to receive the data and returning the data and the size in the
-// reference arguments.
-extern int nni_plat_file_get(const char *, void **, int *);
+// reference arguments.  The data pointer should be freed with nni_free
+// using the supplied size when no longer needed.
+extern int nni_plat_file_get(const char *, void **, size_t *);
 
 // nni_plat_file_delete deletes the named file.
 extern int nni_plat_file_delete(const char *);
 
+// nni_plat_dir_open attempts to "open a directory" for listing.  The
+// handle for further operations is returned in the first argument, and
+// the directory name is supplied in the second.
+extern int nni_plat_dir_open(void **, const char *);
+
+// nni_plat_dir_next gets the next directory entry.  Each call returns
+// a new entry (arbitrary order).  When no more entries exist, it returns
+// NNG_ENOENT.  The returned name is valid until the next call to this
+// function, or until the directory is closed.  Only files are returned,
+// subdirectories are not reported.
+extern int nni_plat_dir_next(void *, const char **);
+
+// nni_plat_dir_close closes the directory handle, freeing all
+// resources associated with it.
+extern void nni_plat_dir_close(void *);
+
+// nni_plat_dir_create creates a directory.  Any parent directories must
+// already exist.  If the directory already exists, 0 is returned.
+extern int nni_plat_dir_create(const char *);
+
+// nni_plat_dir_remove removes a directory, which must already be empty.
+// If it does not exist, 0 is returned.
+extern int nni_plat_dir_remove(const char *);
+
+// nni_plat_temp_dir returns a temporary/scratch directory for the platform
+// The result should be freed with nni_strfree().
+extern char *nni_plat_temp_dir(void);
+
+// nni_plat_home_dir returns the "home" directory for the user running the
+// application.  This is a convenient place to store preferences, etc.
+// Applications should append an application specific directory name.
+// The result should be freed with nni_strfree().
+extern char *nni_plat_home_dir(void);
+
+// nni_plat_join_dir joins to path components to make a path name.
+// For example. on UNIX systems nni_plat_join_dir("/tmp", "a") returns
+// "/tmp/a".  The pathname returned should be freed with nni_strfree().
+extern char *nni_plat_join_dir(const char *, const char *);
+
+//
 // Actual platforms we support.  This is included up front so that we can
 // get the specific types that are supplied by the platform.
 #if defined(NNG_PLATFORM_POSIX)