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authorMichael Haggerty <mhagger@alum.mit.edu>2016-06-18 04:15:18 (GMT)
committerJunio C Hamano <gitster@pobox.com>2016-06-20 18:38:21 (GMT)
commit0fe5043dad74352c08447eb1913df0b6c3f2731c (patch)
tree7ed4e4f4b55b942da556e4c4914a379358c8de0e
parentd24b21e9fcaa9ed4b7966275a8d82406f578577d (diff)
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dir_iterator: new API for iterating over a directory tree
The iterator interface is modeled on that for references, though no vtable is necessary because there is (so far?) only one type of dir_iterator. There are obviously a lot of features that could easily be added to this class: * Skip/include directory paths in the iteration * Shallow/deep iteration * Letting the caller decide which subdirectories to recurse into (e.g., via a dir_iterator_advance_into() function) * Option to iterate in sorted order * Option to iterate over directory paths before vs. after their contents But these are not needed for the current patch series, so I refrain. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--Makefile1
-rw-r--r--dir-iterator.c202
-rw-r--r--dir-iterator.h87
3 files changed, 290 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index ac8f365..b4ffc11 100644
--- a/Makefile
+++ b/Makefile
@@ -722,6 +722,7 @@ LIB_OBJS += diff-lib.o
LIB_OBJS += diff-no-index.o
LIB_OBJS += diff.o
LIB_OBJS += dir.o
+LIB_OBJS += dir-iterator.o
LIB_OBJS += editor.o
LIB_OBJS += entry.o
LIB_OBJS += environment.o
diff --git a/dir-iterator.c b/dir-iterator.c
new file mode 100644
index 0000000..34182a9
--- /dev/null
+++ b/dir-iterator.c
@@ -0,0 +1,202 @@
+#include "cache.h"
+#include "dir.h"
+#include "iterator.h"
+#include "dir-iterator.h"
+
+struct dir_iterator_level {
+ int initialized;
+
+ DIR *dir;
+
+ /*
+ * The length of the directory part of path at this level
+ * (including a trailing '/'):
+ */
+ size_t prefix_len;
+
+ /*
+ * The last action that has been taken with the current entry
+ * (needed for directories, which have to be included in the
+ * iteration and also iterated into):
+ */
+ enum {
+ DIR_STATE_ITER,
+ DIR_STATE_RECURSE
+ } dir_state;
+};
+
+/*
+ * The full data structure used to manage the internal directory
+ * iteration state. It includes members that are not part of the
+ * public interface.
+ */
+struct dir_iterator_int {
+ struct dir_iterator base;
+
+ /*
+ * The number of levels currently on the stack. This is always
+ * at least 1, because when it becomes zero the iteration is
+ * ended and this struct is freed.
+ */
+ size_t levels_nr;
+
+ /* The number of levels that have been allocated on the stack */
+ size_t levels_alloc;
+
+ /*
+ * A stack of levels. levels[0] is the uppermost directory
+ * that will be included in this iteration.
+ */
+ struct dir_iterator_level *levels;
+};
+
+int dir_iterator_advance(struct dir_iterator *dir_iterator)
+{
+ struct dir_iterator_int *iter =
+ (struct dir_iterator_int *)dir_iterator;
+
+ while (1) {
+ struct dir_iterator_level *level =
+ &iter->levels[iter->levels_nr - 1];
+ struct dirent *de;
+
+ if (!level->initialized) {
+ /*
+ * Note: dir_iterator_begin() ensures that
+ * path is not the empty string.
+ */
+ if (!is_dir_sep(iter->base.path.buf[iter->base.path.len - 1]))
+ strbuf_addch(&iter->base.path, '/');
+ level->prefix_len = iter->base.path.len;
+
+ level->dir = opendir(iter->base.path.buf);
+ if (!level->dir && errno != ENOENT) {
+ warning("error opening directory %s: %s",
+ iter->base.path.buf, strerror(errno));
+ /* Popping the level is handled below */
+ }
+
+ level->initialized = 1;
+ } else if (S_ISDIR(iter->base.st.st_mode)) {
+ if (level->dir_state == DIR_STATE_ITER) {
+ /*
+ * The directory was just iterated
+ * over; now prepare to iterate into
+ * it.
+ */
+ level->dir_state = DIR_STATE_RECURSE;
+ ALLOC_GROW(iter->levels, iter->levels_nr + 1,
+ iter->levels_alloc);
+ level = &iter->levels[iter->levels_nr++];
+ level->initialized = 0;
+ continue;
+ } else {
+ /*
+ * The directory has already been
+ * iterated over and iterated into;
+ * we're done with it.
+ */
+ }
+ }
+
+ if (!level->dir) {
+ /*
+ * This level is exhausted (or wasn't opened
+ * successfully); pop up a level.
+ */
+ if (--iter->levels_nr == 0)
+ return dir_iterator_abort(dir_iterator);
+
+ continue;
+ }
+
+ /*
+ * Loop until we find an entry that we can give back
+ * to the caller:
+ */
+ while (1) {
+ strbuf_setlen(&iter->base.path, level->prefix_len);
+ errno = 0;
+ de = readdir(level->dir);
+
+ if (!de) {
+ /* This level is exhausted; pop up a level. */
+ if (errno) {
+ warning("error reading directory %s: %s",
+ iter->base.path.buf, strerror(errno));
+ } else if (closedir(level->dir))
+ warning("error closing directory %s: %s",
+ iter->base.path.buf, strerror(errno));
+
+ level->dir = NULL;
+ if (--iter->levels_nr == 0)
+ return dir_iterator_abort(dir_iterator);
+ break;
+ }
+
+ if (is_dot_or_dotdot(de->d_name))
+ continue;
+
+ strbuf_addstr(&iter->base.path, de->d_name);
+ if (lstat(iter->base.path.buf, &iter->base.st) < 0) {
+ if (errno != ENOENT)
+ warning("error reading path '%s': %s",
+ iter->base.path.buf,
+ strerror(errno));
+ continue;
+ }
+
+ /*
+ * We have to set these each time because
+ * the path strbuf might have been realloc()ed.
+ */
+ iter->base.relative_path =
+ iter->base.path.buf + iter->levels[0].prefix_len;
+ iter->base.basename =
+ iter->base.path.buf + level->prefix_len;
+ level->dir_state = DIR_STATE_ITER;
+
+ return ITER_OK;
+ }
+ }
+}
+
+int dir_iterator_abort(struct dir_iterator *dir_iterator)
+{
+ struct dir_iterator_int *iter = (struct dir_iterator_int *)dir_iterator;
+
+ for (; iter->levels_nr; iter->levels_nr--) {
+ struct dir_iterator_level *level =
+ &iter->levels[iter->levels_nr - 1];
+
+ if (level->dir && closedir(level->dir)) {
+ strbuf_setlen(&iter->base.path, level->prefix_len);
+ warning("error closing directory %s: %s",
+ iter->base.path.buf, strerror(errno));
+ }
+ }
+
+ free(iter->levels);
+ strbuf_release(&iter->base.path);
+ free(iter);
+ return ITER_DONE;
+}
+
+struct dir_iterator *dir_iterator_begin(const char *path)
+{
+ struct dir_iterator_int *iter = xcalloc(1, sizeof(*iter));
+ struct dir_iterator *dir_iterator = &iter->base;
+
+ if (!path || !*path)
+ die("BUG: empty path passed to dir_iterator_begin()");
+
+ strbuf_init(&iter->base.path, PATH_MAX);
+ strbuf_addstr(&iter->base.path, path);
+
+ ALLOC_GROW(iter->levels, 10, iter->levels_alloc);
+
+ iter->levels_nr = 1;
+ iter->levels[0].initialized = 0;
+
+ return dir_iterator;
+}
diff --git a/dir-iterator.h b/dir-iterator.h
new file mode 100644
index 0000000..27739e6
--- /dev/null
+++ b/dir-iterator.h
@@ -0,0 +1,87 @@
+#ifndef DIR_ITERATOR_H
+#define DIR_ITERATOR_H
+
+/*
+ * Iterate over a directory tree.
+ *
+ * Iterate over a directory tree, recursively, including paths of all
+ * types and hidden paths. Skip "." and ".." entries and don't follow
+ * symlinks except for the original path.
+ *
+ * Every time dir_iterator_advance() is called, update the members of
+ * the dir_iterator structure to reflect the next path in the
+ * iteration. The order that paths are iterated over within a
+ * directory is undefined, but directory paths are always iterated
+ * over before the subdirectory contents.
+ *
+ * A typical iteration looks like this:
+ *
+ * int ok;
+ * struct iterator *iter = dir_iterator_begin(path);
+ *
+ * while ((ok = dir_iterator_advance(iter)) == ITER_OK) {
+ * if (want_to_stop_iteration()) {
+ * ok = dir_iterator_abort(iter);
+ * break;
+ * }
+ *
+ * // Access information about the current path:
+ * if (S_ISDIR(iter->st.st_mode))
+ * printf("%s is a directory\n", iter->relative_path);
+ * }
+ *
+ * if (ok != ITER_DONE)
+ * handle_error();
+ *
+ * Callers are allowed to modify iter->path while they are working,
+ * but they must restore it to its original contents before calling
+ * dir_iterator_advance() again.
+ */
+
+struct dir_iterator {
+ /* The current path: */
+ struct strbuf path;
+
+ /*
+ * The current path relative to the starting path. This part
+ * of the path always uses "/" characters to separate path
+ * components:
+ */
+ const char *relative_path;
+
+ /* The current basename: */
+ const char *basename;
+
+ /* The result of calling lstat() on path: */
+ struct stat st;
+};
+
+/*
+ * Start a directory iteration over path. Return a dir_iterator that
+ * holds the internal state of the iteration.
+ *
+ * The iteration includes all paths under path, not including path
+ * itself and not including "." or ".." entries.
+ *
+ * path is the starting directory. An internal copy will be made.
+ */
+struct dir_iterator *dir_iterator_begin(const char *path);
+
+/*
+ * Advance the iterator to the first or next item and return ITER_OK.
+ * If the iteration is exhausted, free the dir_iterator and any
+ * resources associated with it and return ITER_DONE. On error, free
+ * dir_iterator and associated resources and return ITER_ERROR. It is
+ * a bug to use iterator or call this function again after it has
+ * returned ITER_DONE or ITER_ERROR.
+ */
+int dir_iterator_advance(struct dir_iterator *iterator);
+
+/*
+ * End the iteration before it has been exhausted. Free the
+ * dir_iterator and any associated resources and return ITER_DONE. On
+ * error, free the dir_iterator and return ITER_ERROR.
+ */
+int dir_iterator_abort(struct dir_iterator *iterator);
+
+#endif