3 files changed, 179 insertions, 1 deletions

diff --git a/tools/lib/api/Makefile b/tools/lib/api/Makefile
index ce00f7ee6455..36c08b1f4afb 100644
--- a/tools/lib/api/Makefile
+++ b/tools/lib/api/Makefile
@@ -10,9 +10,14 @@ LIB_OBJS=
 
 LIB_H += fs/debugfs.h
 LIB_H += fs/fs.h
+# See comment below about piggybacking...
+LIB_H += fd/array.h
 
 LIB_OBJS += $(OUTPUT)fs/debugfs.o
 LIB_OBJS += $(OUTPUT)fs/fs.o
+# XXX piggybacking here, need to introduce libapikfd, or rename this
+# to plain libapik.a and make it have it all api goodies
+LIB_OBJS += $(OUTPUT)fd/array.o
 
 LIBFILE = libapikfs.a
 
@@ -29,7 +34,7 @@ $(LIBFILE): $(LIB_OBJS)
 $(LIB_OBJS): $(LIB_H)
 
 libapi_dirs:
-        $(QUIET_MKDIR)mkdir -p $(OUTPUT)fs/
+        $(QUIET_MKDIR)mkdir -p $(OUTPUT)fd $(OUTPUT)fs
 
 $(OUTPUT)%.o: %.c libapi_dirs
         $(QUIET_CC)$(CC) -o $@ -c $(ALL_CFLAGS) $<
diff --git a/tools/lib/api/fd/array.c b/tools/lib/api/fd/array.c
new file mode 100644
index 000000000000..0e636c4339b8
--- /dev/null
+++ b/tools/lib/api/fd/array.c
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2014, Red Hat Inc, Arnaldo Carvalho de Melo <acme@redhat.com>
+ *
+ * Released under the GPL v2. (and only v2, not any later version)
+ */
+#include "array.h"
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+void fdarray__init(struct fdarray *fda, int nr_autogrow)
+{
+        fda->entries     = NULL;
+        fda->priv        = NULL;
+        fda->nr          = fda->nr_alloc = 0;
+        fda->nr_autogrow = nr_autogrow;
+}
+
+int fdarray__grow(struct fdarray *fda, int nr)
+{
+        void *priv;
+        int nr_alloc = fda->nr_alloc + nr;
+        size_t psize = sizeof(fda->priv[0]) * nr_alloc;
+        size_t size  = sizeof(struct pollfd) * nr_alloc;
+        struct pollfd *entries = realloc(fda->entries, size);
+
+        if (entries == NULL)
+                return -ENOMEM;
+
+        priv = realloc(fda->priv, psize);
+        if (priv == NULL) {
+                free(entries);
+                return -ENOMEM;
+        }
+
+        fda->nr_alloc = nr_alloc;
+        fda->entries  = entries;
+        fda->priv     = priv;
+        return 0;
+}
+
+struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow)
+{
+        struct fdarray *fda = calloc(1, sizeof(*fda));
+
+        if (fda != NULL) {
+                if (fdarray__grow(fda, nr_alloc)) {
+                        free(fda);
+                        fda = NULL;
+                } else {
+                        fda->nr_autogrow = nr_autogrow;
+                }
+        }
+
+        return fda;
+}
+
+void fdarray__exit(struct fdarray *fda)
+{
+        free(fda->entries);
+        free(fda->priv);
+        fdarray__init(fda, 0);
+}
+
+void fdarray__delete(struct fdarray *fda)
+{
+        fdarray__exit(fda);
+        free(fda);
+}
+
+int fdarray__add(struct fdarray *fda, int fd, short revents)
+{
+        int pos = fda->nr;
+
+        if (fda->nr == fda->nr_alloc &&
+            fdarray__grow(fda, fda->nr_autogrow) < 0)
+                return -ENOMEM;
+
+        fda->entries[fda->nr].fd     = fd;
+        fda->entries[fda->nr].events = revents;
+        fda->nr++;
+        return pos;
+}
+
+int fdarray__filter(struct fdarray *fda, short revents,
+                    void (*entry_destructor)(struct fdarray *fda, int fd))
+{
+        int fd, nr = 0;
+
+        if (fda->nr == 0)
+                return 0;
+
+        for (fd = 0; fd < fda->nr; ++fd) {
+                if (fda->entries[fd].revents & revents) {
+                        if (entry_destructor)
+                                entry_destructor(fda, fd);
+
+                        continue;
+                }
+
+                if (fd != nr) {
+                        fda->entries[nr] = fda->entries[fd];
+                        fda->priv[nr]    = fda->priv[fd];
+                }
+
+                ++nr;
+        }
+
+        return fda->nr = nr;
+}
+
+int fdarray__poll(struct fdarray *fda, int timeout)
+{
+        return poll(fda->entries, fda->nr, timeout);
+}
+
+int fdarray__fprintf(struct fdarray *fda, FILE *fp)
+{
+        int fd, printed = fprintf(fp, "%d [ ", fda->nr);
+
+        for (fd = 0; fd < fda->nr; ++fd)
+                printed += fprintf(fp, "%s%d", fd ? ", " : "", fda->entries[fd].fd);
+
+        return printed + fprintf(fp, " ]");
+}
diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
new file mode 100644
index 000000000000..45db01818f45
--- /dev/null
+++ b/tools/lib/api/fd/array.h
@@ -0,0 +1,46 @@
+#ifndef __API_FD_ARRAY__
+#define __API_FD_ARRAY__
+
+#include <stdio.h>
+
+struct pollfd;
+
+/**
+ * struct fdarray: Array of file descriptors
+ *
+ * @priv: Per array entry priv area, users should access just its contents,
+ *        not set it to anything, as it is kept in synch with @entries, being
+ *        realloc'ed, * for instance, in fdarray__{grow,filter}.
+ *
+ *        I.e. using 'fda->priv[N].idx = * value' where N < fda->nr is ok,
+ *        but doing 'fda->priv = malloc(M)' is not allowed.
+ */
+struct fdarray {
+        int            nr;
+        int            nr_alloc;
+        int            nr_autogrow;
+        struct pollfd *entries;
+        union {
+                int    idx;
+        } *priv;
+};
+
+void fdarray__init(struct fdarray *fda, int nr_autogrow);
+void fdarray__exit(struct fdarray *fda);
+
+struct fdarray *fdarray__new(int nr_alloc, int nr_autogrow);
+void fdarray__delete(struct fdarray *fda);
+
+int fdarray__add(struct fdarray *fda, int fd, short revents);
+int fdarray__poll(struct fdarray *fda, int timeout);
+int fdarray__filter(struct fdarray *fda, short revents,
+                    void (*entry_destructor)(struct fdarray *fda, int fd));
+int fdarray__grow(struct fdarray *fda, int extra);
+int fdarray__fprintf(struct fdarray *fda, FILE *fp);
+
+static inline int fdarray__available_entries(struct fdarray *fda)
+{
+        return fda->nr_alloc - fda->nr;
+}
+
+#endif /* __API_FD_ARRAY__ */