filter: Add write-to CRLF filter

1 files changed, 193 insertions, 0 deletions

diff --git a/src/crlf.c b/src/crlf.c
new file mode 100644
index 000000000..d8dd1c382
--- /dev/null
+++ b/src/crlf.c
@@ -0,0 +1,193 @@
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "common.h"
+#include "fileops.h"
+#include "hash.h"
+#include "filter.h"
+#include "repository.h"
+
+#include "git2/attr.h"
+
+struct crlf_attrs {
+	int crlf_action;
+	int eol;
+};
+
+struct crlf_filter {
+	git_filter f;
+	struct crlf_attrs attrs;
+};
+
+static int check_crlf(const char *value)
+{
+	if (value == git_attr__true)
+		return GIT_CRLF_TEXT;
+
+	if (value == git_attr__false)
+		return GIT_CRLF_BINARY;
+
+	if (value == NULL)
+		return GIT_CRLF_GUESS;
+
+	if (strcmp(value, "input") == 0)
+		return GIT_CRLF_INPUT;
+
+	if (strcmp(value, "auto") == 0)
+		return GIT_CRLF_AUTO;
+
+	return GIT_CRLF_GUESS;
+}
+
+static int check_eol(const char *value)
+{
+	if (value == NULL)
+		return GIT_EOL_UNSET;
+
+	if (strcmp(value, "lf") == 0)
+		return GIT_EOL_LF;
+
+	if (strcmp(value, "crlf") == 0)
+		return GIT_EOL_CRLF;
+
+	return GIT_EOL_UNSET;
+}
+
+static int crlf_input_action(struct crlf_attrs *ca)
+{
+	if (ca->crlf_action == GIT_CRLF_BINARY)
+		return GIT_CRLF_BINARY;
+
+	if (ca->eol == GIT_EOL_LF)
+		return GIT_CRLF_INPUT;
+
+	if (ca->eol == GIT_EOL_CRLF)
+		return GIT_CRLF_CRLF;
+
+	return ca->crlf_action;
+}
+
+static int crlf_load_attributes(struct crlf_attrs *ca, git_repository *repo, const char *path)
+{
+#define NUM_CONV_ATTRS 3
+
+	static const char *attr_names[NUM_CONV_ATTRS] = {
+		"crlf", "eol", "text",
+	};
+
+	const char *attr_vals[NUM_CONV_ATTRS];
+	int error;
+
+	error = git_attr_get_many(repo, path, NUM_CONV_ATTRS, attr_names, attr_vals);
+
+	if (error == GIT_ENOTFOUND) {
+		ca->crlf_action = GIT_CRLF_GUESS;
+		ca->eol = GIT_EOL_UNSET;
+		return 0;
+	}
+
+	if (error == GIT_SUCCESS) {
+		ca->crlf_action = check_crlf(attr_vals[2]); /* text */
+		if (ca->crlf_action == GIT_CRLF_GUESS)
+			ca->crlf_action = check_crlf(attr_vals[0]); /* clrf */
+
+		ca->eol = check_eol(attr_vals[1]); /* eol */
+		return 0;
+	}
+
+	return error;
+}
+
+static int crlf_apply_to_odb(git_filter *self, git_buf *dest, const git_buf *source)
+{
+	size_t i = 0;
+	struct crlf_filter *filter = (struct crlf_filter *)self;
+
+	assert(self && dest && source);
+
+	if (filter->attrs.crlf_action == GIT_CRLF_AUTO ||
+		filter->attrs.crlf_action == GIT_CRLF_GUESS) {
+
+		git_text_stats stats;
+		git_text__stat(&stats, source);
+
+		/*
+		 * We're currently not going to even try to convert stuff
+		 * that has bare CR characters. Does anybody do that crazy
+		 * stuff?
+		 */
+		if (stats.cr != stats.crlf)
+			return -1;
+
+		/*
+		 * And add some heuristics for binary vs text, of course...
+		 */
+		if (git_text__is_binary(&stats))
+			return -1;
+
+#if 0
+		if (crlf_action == CRLF_GUESS) {
+			/*
+			 * If the file in the index has any CR in it, do not convert.
+			 * This is the new safer autocrlf handling.
+			 */
+			if (has_cr_in_index(path))
+				return 0;
+		}
+#endif
+
+		if (!stats.cr)
+			return -1;
+	}
+
+	/* TODO: do not copy anything if there isn't a single CR */
+	while (i < source->size) {
+		size_t org = i;
+
+		while (i < source->size && source->ptr[i] != '\r')
+			i++;
+
+		if (i > org)
+			git_buf_put(dest, source->ptr + org, i - org);
+
+		i++;
+
+		if (i >= source->size || source->ptr[i] != '\n') {
+			git_buf_putc(dest, '\r');
+		}
+	}
+
+	return 0;
+}
+
+int git_filter__crlf_to_odb(git_filter **filter_out, git_repository *repo, const char *path)
+{
+	struct crlf_filter filter;
+	int error;
+
+	filter.f.apply = &crlf_apply_to_odb;
+	filter.f.do_free = NULL;
+
+	if ((error = crlf_load_attributes(&filter.attrs, repo, path)) < 0)
+		return error;
+
+	filter.attrs.crlf_action = crlf_input_action(&filter.attrs);
+
+	if (filter.attrs.crlf_action == GIT_CRLF_BINARY)
+		return 0;
+
+	if (filter.attrs.crlf_action == GIT_CRLF_GUESS && repo->filter_options.auto_crlf == GIT_AUTO_CRLF_FALSE)
+		return 0;
+
+	*filter_out = git__malloc(sizeof(struct crlf_filter));
+	if (*filter_out == NULL)
+		return GIT_ENOMEM;
+
+	memcpy(*filter_out, &filter, sizeof(struct crlf_attrs));
+	return 0;
+}
+