tools lib api: Adopt fdarray class from perf's evlist

The extensible file description array that grew in the perf_evlist class
can be useful for other tools, as it is not something that only evlists
need, so move it to tools/lib/api/fd to ease sharing it.

v2: Don't use {} like in:

 libapi_dirs:
	$(QUIET_MKDIR)mkdir -p $(OUTPUT){fs,fd}/

in Makefiles, as it will not work in some systems, as in ubuntu13.10.

v3: Add fd/*.[ch] to LIBAPIKFS_SOURCES (Fix from Jiri Olsa)

v4: Leave the fcntl(fd, O_NONBLOCK) in the evlist layer, remains to
    be checked if it is really needed there, but has no place in the
    fdarray class (Fix from Jiri Olsa)

v5: Remove evlist details from fdarray grow/filter tests. Improve it a
    bit doing more tests about expected internal state.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-kleuni3hckbc3s0lu6yb9x40@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 145 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..4889c7d42961
--- /dev/null
+++ b/tools/lib/api/fd/array.c
@@ -0,0 +1,107 @@
+/*
+ * 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->nr          = fda->nr_alloc = 0;
+        fda->nr_autogrow = nr_autogrow;
+}
+
+int fdarray__grow(struct fdarray *fda, int nr)
+{
+        int nr_alloc = fda->nr_alloc + nr;
+        size_t size  = sizeof(struct pollfd) * nr_alloc;
+        struct pollfd *entries = realloc(fda->entries, size);
+
+        if (entries == NULL)
+                return -ENOMEM;
+
+        fda->nr_alloc = nr_alloc;
+        fda->entries  = entries;
+        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);
+        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)
+{
+        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 0;
+}
+
+int fdarray__filter(struct fdarray *fda, short revents)
+{
+        int fd, nr = 0;
+
+        if (fda->nr == 0)
+                return 0;
+
+        for (fd = 0; fd < fda->nr; ++fd) {
+                if (fda->entries[fd].revents & revents)
+                        continue;
+
+                if (fd != nr)
+                        fda->entries[nr] = fda->entries[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..de38361ba69e
--- /dev/null
+++ b/tools/lib/api/fd/array.h
@@ -0,0 +1,32 @@
+#ifndef __API_FD_ARRAY__
+#define __API_FD_ARRAY__
+
+#include <stdio.h>
+
+struct pollfd;
+
+struct fdarray {
+        int            nr;
+        int            nr_alloc;
+        int            nr_autogrow;
+        struct pollfd *entries;
+};
+
+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);
+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__ */