Refactored file API.

This refactor of the file API provides a simpler and easier to use
interface for our needs (and simpler to implement) in both the
ZeroTier transport and the HTTP/TLS file accesses.  It also removes
some restrictions present on the old one, although it is still not
suitable for working with large files.  (It will work, just be
very inefficient as the entire file must be loaded into memory.)

4 files changed, 232 insertions, 4 deletions

diff --git a/src/core/file.c b/src/core/file.c
new file mode 100644
index 00000000..d7000a6a
--- /dev/null
+++ b/src/core/file.c
@@ -0,0 +1,111 @@
+//
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This software is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+#include "core/nng_impl.h"
+
+int
+nni_file_put(const char *name, const void *data, size_t sz)
+{
+	return (nni_plat_file_put(name, data, sz));
+}
+
+int
+nni_file_get(const char *name, void **datap, size_t *szp)
+{
+	return (nni_plat_file_get(name, datap, szp));
+}
+
+int
+nni_file_delete(const char *name)
+{
+	return (nni_plat_file_delete(name));
+}
+
+struct walkdata {
+	nni_file_walker fn;
+	void *          arg;
+};
+
+static int
+plat_walker(const char *name, void *arg)
+{
+	struct walkdata *w = arg;
+	int              rv;
+
+	rv = w->fn(name, w->arg);
+	switch (rv) {
+	case NNI_FILE_WALK_CONTINUE:
+		return (NNI_PLAT_FILE_WALK_CONTINUE);
+	case NNI_FILE_WALK_STOP:
+		return (NNI_PLAT_FILE_WALK_STOP);
+	case NNI_FILE_WALK_PRUNE_CHILD:
+		return (NNI_PLAT_FILE_WALK_PRUNE_CHILD);
+	case NNI_FILE_WALK_PRUNE_SIB:
+		return (NNI_PLAT_FILE_WALK_PRUNE_SIB);
+	}
+	// We treat any other value as a stop condition.  The program
+	// is returning something invalid.
+	return (NNI_PLAT_FILE_WALK_STOP);
+}
+
+int
+nni_file_walk(const char *name, nni_file_walker walker, void *arg, int flags)
+{
+	struct walkdata w;
+	int             wflags = 0;
+
+	w.fn  = walker;
+	w.arg = arg;
+
+	if (flags & NNI_FILE_WALK_FILES_ONLY) {
+		wflags |= NNI_PLAT_FILE_WALK_FILES_ONLY;
+	}
+	if (flags & NNI_FILE_WALK_SHALLOW) {
+		wflags |= NNI_PLAT_FILE_WALK_SHALLOW;
+	}
+
+	return (nni_plat_file_walk(name, plat_walker, &w, wflags));
+}
+
+int
+nni_file_type(const char *name, int *ftype)
+{
+	int rv;
+	int t;
+
+	if ((rv = nni_plat_file_type(name, &t)) != 0) {
+		return (rv);
+	}
+
+	switch (t) {
+	case NNI_PLAT_FILE_TYPE_FILE:
+		*ftype = NNI_FILE_TYPE_FILE;
+		break;
+	case NNI_PLAT_FILE_TYPE_DIR:
+		*ftype = NNI_FILE_TYPE_DIR;
+		break;
+	default:
+		*ftype = NNI_FILE_TYPE_OTHER;
+		break;
+	}
+	return (0);
+}
+
+char *
+nni_file_join(const char *dir, const char *file)
+{
+	return (nni_plat_join_dir(dir, file));
+}
+
+const char *
+nni_file_basename(const char *path)
+{
+	return (nni_plat_file_basename(path));
+}
\ No newline at end of file
diff --git a/src/core/file.h b/src/core/file.h
new file mode 100644
index 00000000..b45aae61
--- /dev/null
+++ b/src/core/file.h
@@ -0,0 +1,79 @@
+//
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This software is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+#ifndef CORE_FILE_H
+#define CORE_FILE_H
+
+// File/Store Support
+//
+// Some transports require a persistent storage for things like configs,
+// key material, etc.  Generally, these are all going to be relatively
+// small objects (such as certificates), so we only require a synchronous
+// implementation from platforms.  We provide a very limited and simple
+// file API for these purposes; basic CRUD operations only, plus a way
+// to iterate over names.  These are adequate for NNG's internal uses;
+// applications should use normal platform-specific APIs or those in the
+// standard C library.
+
+// nni_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 will allow the application to read and
+// write the file, but may (should) restrict anything else beyond that
+// where they can.  If the name contains platform specific directory
+// separators, then any missing parent directories will be created if
+// possible.
+extern int nni_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.  The data pointer should be freed with nni_free
+// using the supplied size when no longer needed.
+extern int nni_file_get(const char *, void **, size_t *);
+
+// nni_file_delete deletes the named file.
+extern int nni_file_delete(const char *);
+
+enum nni_file_type_val {
+	NNI_FILE_TYPE_FILE,
+	NNI_FILE_TYPE_DIR,
+	NNI_FILE_TYPE_OTHER,
+};
+
+// nni_file_exists checks if the named file exists.
+extern int nni_file_type(const char *, int *);
+
+// nni_file_walk walks a list of files.
+enum nni_file_walk_result {
+	NNI_FILE_WALK_CONTINUE,
+	NNI_FILE_WALK_STOP,
+	NNI_FILE_WALK_PRUNE_SIB,
+	NNI_FILE_WALK_PRUNE_CHILD,
+};
+
+enum nni_file_walk_flags {
+	NNI_FILE_WALK_DEPTH_FIRST   = 0, // get children first
+	NNI_FILE_WALK_BREADTH_FIRST = 1, // get siblings first (later)
+	NNI_FILE_WALK_SHALLOW       = 2, // do not descend into subdirectories
+	NNI_FILE_WALK_FILES_ONLY    = 4, // directory names are not reported
+};
+
+typedef int (*nni_file_walker)(const char *, void *);
+extern int nni_file_walk(const char *, nni_file_walker, void *, int);
+
+// nni_file_join joins two path components to make a path name.
+// For example. on UNIX systems nni_file_join("/tmp", "a") returns
+// "/tmp/a".  The pathname returned should be freed with nni_strfree().
+extern char *nni_file_join(const char *, const char *);
+
+// nni_file_basename returns the "file" name, without the parent directory.
+// The returned value generally is within the supplied path name.
+extern const char *nni_file_basename(const char *);
+
+#endif // CORE_FILE_H
diff --git a/src/core/nng_impl.h b/src/core/nng_impl.h
index bee6ae41..ea8512bb 100644
--- a/src/core/nng_impl.h
+++ b/src/core/nng_impl.h
@@ -29,6 +29,7 @@
 #include "core/aio.h"
 #include "core/clock.h"
 #include "core/device.h"
+#include "core/file.h"
 #include "core/idhash.h"
 #include "core/init.h"
 #include "core/list.h"
diff --git a/src/core/platform.h b/src/core/platform.h
index 9e193175..73b6785b 100644
--- a/src/core/platform.h
+++ b/src/core/platform.h
@@ -1,6 +1,6 @@
 //
-// Copyright 2017 Garrett D'Amore <garrett@damore.org>
-// Copyright 2017 Capitar IT Group BV <info@capitar.com>
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
 //
 // This software is supplied under the terms of the MIT License, a
 // copy of which should be located in the distribution where this
@@ -370,7 +370,7 @@ extern void nni_plat_pipe_close(int, int);
 //
 // Some transports require a persistent storage for things like
 // key material, etc.  Generally, these are all going to be relatively
-// small objects (such as certificates), so we ony require a synchronous
+// small objects (such as certificates), so we only require a synchronous
 // implementation from platforms.  This Key-Value API is intended to
 // to support using the Key's as filenames, and keys will consist of
 // only these characters: [0-9a-zA-Z._-].  The directory used should be
@@ -393,9 +393,41 @@ extern int nni_plat_file_put(const char *, const void *, size_t);
 // 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.
+// nni_plat_file_delete deletes the named file.  If the name refers to
+// a directory, then that will be removed only if empty.
 extern int nni_plat_file_delete(const char *);
 
+// nni_plat_file_check checks the file path to determine its type.
+// If the path does not exist, then NNG_ENOENT is returned.
+enum nni_plat_file_type_val {
+	NNI_PLAT_FILE_TYPE_FILE,  // normal file
+	NNI_PLAT_FILE_TYPE_DIR,   // normal directory
+	NNI_PLAT_FILE_TYPE_OTHER, // something else (pipe, device node, etc.)
+};
+extern int nni_plat_file_type(const char *, int *);
+
+enum nni_plat_file_walk_result {
+	NNI_PLAT_FILE_WALK_CONTINUE,
+	NNI_PLAT_FILE_WALK_STOP,        // stop walking (all done)
+	NNI_PLAT_FILE_WALK_PRUNE_SIB,   // skip siblings and their children
+	NNI_PLAT_FILE_WALK_PRUNE_CHILD, // skip children
+};
+
+enum nni_plat_file_walk_flags {
+	NNI_PLAT_FILE_WALK_DEPTH_FIRST   = 0, // get children first
+	NNI_PLAT_FILE_WALK_BREADTH_FIRST = 1, // get siblings first (later)
+	NNI_PLAT_FILE_WALK_SHALLOW = 2, // do not descend into subdirectories
+	NNI_PLAT_FILE_WALK_FILES_ONLY = 4, // directory names are not reported
+};
+
+// nni_plat_file_walker is called for each pathname found by walking a
+// directory tree.  It returns one of the nni_plat_file_walk_result values.
+typedef int (*nni_plat_file_walker)(const char *, void *);
+
+// nni_plat_file_walk walks a directory tree, calling the walker function
+// with the path name, and the supplied void * argument.
+extern int nni_plat_file_walk(const char *, nni_plat_file_walker, void *, int);
+
 // 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.
@@ -435,6 +467,11 @@ extern char *nni_plat_home_dir(void);
 // "/tmp/a".  The pathname returned should be freed with nni_strfree().
 extern char *nni_plat_join_dir(const char *, const char *);
 
+// nni_plat_file_basename returns the "file" part of the file name.
+// The returned pointer will usually reference the end of the supplied
+// string, and may not be altered.
+extern const char *nni_plat_file_basename(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.