Add initial parser for git trees

It doesn't actually parse the files themselves, but it does walk the
object tree and print out the dives and trips it finds.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 294 insertions, 0 deletions

diff --git a/load-git.c b/load-git.c
new file mode 100644
index 000000000..9a1b4708d
--- /dev/null
+++ b/load-git.c
@@ -0,0 +1,294 @@
+#include <stdio.h>
+#include <ctype.h>
+#include <string.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <git2.h>
+
+#include "dive.h"
+#include "device.h"
+#include "membuffer.h"
+
+#define GIT_WALK_OK   0
+#define GIT_WALK_SKIP 1
+
+static struct dive *active_dive;
+static dive_trip_t *active_trip;
+
+static struct dive *create_new_dive(timestamp_t when)
+{
+	struct tm tm;
+	struct dive *dive = alloc_dive();
+
+	/* We'll fill in more data from the dive file */
+	dive->when = when;
+
+	utc_mkdate(when, &tm);
+	report_error("New dive: %04u-%02u-%02u %02u:%02u:%02u",
+		tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
+		tm.tm_hour, tm.tm_min, tm.tm_sec);
+
+	return dive;
+}
+
+static dive_trip_t *create_new_trip(int yyyy, int mm, int dd)
+{
+	dive_trip_t *trip = calloc(1, sizeof(dive_trip_t));
+	struct tm tm = { 0 };
+
+	/* We'll fill in the real data from the trip descriptor file */
+	tm.tm_year = yyyy;
+	tm.tm_mon = mm-1;
+	tm.tm_mday = dd;
+	trip->when = utc_mktime(&tm);
+
+	report_error("New trip: %04u-%02u-%02u",
+		tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday);
+
+	return trip;
+}
+
+static bool validate_date(int yyyy, int mm, int dd)
+{
+	return yyyy > 1970 && yyyy < 3000 &&
+		mm > 0 && mm < 13 &&
+		dd > 0 && dd < 32;
+}
+
+static bool validate_time(int h, int m, int s)
+{
+	return h >= 0 && h < 24 &&
+		m >= 0 && m < 60 &&
+		s >=0 && s <= 60;
+}
+
+/*
+ * Dive trip directory, name is 'nn-alphabetic[~hex]'
+ */
+static int dive_trip_directory(const char *root, const char *name)
+{
+	int yyyy = -1, mm = -1, dd = -1;
+
+	if (sscanf(root, "%d/%d", &yyyy, &mm) != 2)
+		return GIT_WALK_SKIP;
+	dd = atoi(name);
+	if (!validate_date(yyyy, mm, dd))
+		return GIT_WALK_SKIP;
+	active_trip = create_new_trip(yyyy, mm, dd);
+	return GIT_WALK_OK;
+}
+
+/*
+ * Dive directory, name is [[yyyy-]mm-]nn-ddd-hh:mm:ss[~hex],
+ * and 'timeoff' points to what should be the time part of
+ * the name (the first digit of the hour).
+ *
+ * The root path will be of the form yyyy/mm[/tripdir],
+ */
+static int dive_directory(const char *root, const char *name, int timeoff)
+{
+	int yyyy = -1, mm = -1, dd = -1;
+	int h, m, s;
+	int mday_off = timeoff - 7;
+	int month_off = mday_off - 3;
+	int year_off = month_off - 5;
+	struct tm tm;
+
+	/* There has to be a mday */
+	if (mday_off < 0)
+		return GIT_WALK_SKIP;
+	if (name[timeoff-1] != '-')
+		return GIT_WALK_SKIP;
+
+	/* Get the time of day */
+	if (sscanf(name+timeoff, "%d:%d:%d", &h, &m, &s) != 3)
+		return GIT_WALK_SKIP;
+	if (!validate_time(h, m, s))
+		return GIT_WALK_SKIP;
+
+	/*
+	 * Get the date. The day of the month is in the dive directory
+	 * name, the year and month might be in the path leading up
+	 * to it.
+	 */
+	dd = atoi(name + mday_off);
+	if (year_off < 0) {
+		if (sscanf(root, "%d/%d", &yyyy, &mm) != 2)
+			return GIT_WALK_SKIP;
+	} else
+		yyyy = atoi(name + year_off);
+	if (month_off >= 0)
+		mm = atoi(name + month_off);
+
+	if (!validate_date(yyyy, mm, dd))
+		return GIT_WALK_SKIP;
+
+	/* Ok, close enough. We've gotten sufficient information */
+	memset(&tm, 0, sizeof(tm));
+	tm.tm_hour = h;
+	tm.tm_min = m;
+	tm.tm_sec = s;
+	tm.tm_year = yyyy - 1900;
+	tm.tm_mon = mm-1;
+	tm.tm_mday = dd;
+
+	active_dive = create_new_dive(utc_mktime(&tm));
+	return GIT_WALK_OK;
+}
+
+/*
+ * Return the length of the string without the unique part.
+ */
+static int nonunique_length(const char *str)
+{
+	int len = 0;
+
+	for (;;) {
+		char c = *str++;
+		if (!c || c == '~')
+			return len;
+		len++;
+	}
+}
+
+/*
+ * When hitting a directory node, we have a couple of cases:
+ *
+ *  - It's just a date entry - all numeric (either year or month):
+ *
+ *       [yyyy|mm]
+ *
+ *    We don't do anything with these, we just traverse into them.
+ *    The numeric data will show up as part of the full path when
+ *    we hit more interesting entries.
+ *
+ *  - It's a trip directory. The name will be of the form
+ *
+ *       nn-alphabetic[~hex]
+ *
+ *    where 'nn' is the day of the month (year and month will be
+ *    encoded in the path leading up to this).
+ *
+ *  - It's a dive directory. The name will be of the form
+ *
+ *       [[yyyy-]mm-]nn-ddd-hh:mm:ss[~hex]
+ *
+ *    which describes the date and time of a dive (yyyy and mm
+ *    are optional, and may be encoded in the path leading up to
+ *    the dive).
+ *
+ *  - It's some random non-dive-data directory.
+ *
+ *    Subsurface doesn't create these yet, but maybe we'll encode
+ *    pictures etc. If it doesn't match the above patterns, we'll
+ *    ignore them for dive loading purposes, and not even recurse
+ *    into them.
+ */
+static int walk_tree_directory(const char *root, const git_tree_entry *entry)
+{
+	const char *name = git_tree_entry_name(entry);
+	int digits = 0, len;
+	char c;
+
+	while (isdigit(c = name[digits]))
+		digits++;
+
+	/* Doesn't start with two or four digits? Skip */
+	if (digits != 4 && digits != 2)
+		return GIT_WALK_SKIP;
+
+	/* Only digits? Do nothing, but recurse into it */
+	if (!c)
+		return GIT_WALK_OK;
+
+	/* All valid cases need to have a slash following */
+	if (c != '-')
+		return GIT_WALK_SKIP;
+
+	/* Do a quick check for a common dive case */
+	len = nonunique_length(name);
+
+	/*
+	 * We know the len is at least 3, because we had at least
+	 * two digits and a dash
+	 */
+	if (name[len-3] == ':')
+		return dive_directory(root, name, len-8);
+
+	if (digits != 2)
+		return GIT_WALK_SKIP;
+
+	return dive_trip_directory(root, name);
+}
+
+static int walk_tree_file(const char *root, const git_tree_entry *entry)
+{
+	/* Parse actual dive/trip data here */
+	return GIT_WALK_OK;
+}
+
+static int walk_tree_cb(const char *root, const git_tree_entry *entry, void *payload)
+{
+	git_filemode_t mode = git_tree_entry_filemode(entry);
+
+	if (mode == GIT_FILEMODE_TREE)
+		return walk_tree_directory(root, entry);
+
+	return walk_tree_file(root, entry);
+}
+
+static int load_dives_from_tree(git_repository *repo, git_tree *tree)
+{
+	git_tree_walk(tree, GIT_TREEWALK_PRE, walk_tree_cb, NULL);
+	return 0;
+}
+
+static int do_git_load(git_repository *repo, const char *branch)
+{
+	int ret;
+	git_reference *ref;
+	git_object *tree;
+
+	ret = git_branch_lookup(&ref, repo, branch, GIT_BRANCH_LOCAL);
+	if (ret)
+		return report_error("Unable to look up branch '%s'", branch);
+	if (git_reference_peel(&tree, ref, GIT_OBJ_TREE))
+		return report_error("Could not look up tree of branch '%s'", branch);
+	ret = load_dives_from_tree(repo, (git_tree *) tree);
+	git_object_free(tree);
+	return ret;
+}
+
+int git_load_dives(char *where)
+{
+	int ret, len;
+	git_repository *repo;
+	char *loc, *branch;
+
+	/* Jump over the "git" marker */
+	loc = where + 3;
+	while (isspace(*loc))
+		loc++;
+
+	/* Trim whitespace from the end */
+	len = strlen(loc);
+	while (len && isspace(loc[len-1]))
+		loc[--len] = 0;
+
+	/* Find a branch name if there is any */
+	branch = strrchr(loc, ':');
+	if (branch)
+		*branch++ = 0;
+
+	if (git_repository_open(&repo, loc))
+		return report_error("Unable to open git repository at '%s' (branch '%s')", loc, branch);
+
+	ret = do_git_load(repo, branch);
+	git_repository_free(repo);
+	return ret;
+}