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From: sxenos@google.com
To: git@vger.kernel.org
Cc: Stefan Xenos <sxenos@google.com>
Subject: [PATCH 4/8] evolve: Add support for parsing metacommits
Date: Mon, 21 Jan 2019 14:32:12 -0800	[thread overview]
Message-ID: <20190121223216.66659-4-sxenos@google.com> (raw)
In-Reply-To: <20190121223216.66659-1-sxenos@google.com>

From: Stefan Xenos <sxenos@google.com>

This patch adds the get_metacommit_content method, which can classify
commits as either metacommits or normal commits, determine whether they
are abandoned, and extract the content commit's object id from the
metacommit.
---
 Makefile            |  1 +
 metacommit-parser.c | 87 +++++++++++++++++++++++++++++++++++++++++++++
 metacommit-parser.h | 16 +++++++++
 3 files changed, 104 insertions(+)
 create mode 100644 metacommit-parser.c
 create mode 100644 metacommit-parser.h

diff --git a/Makefile b/Makefile
index 1a44c811aa..7ffc383f2b 100644
--- a/Makefile
+++ b/Makefile
@@ -919,6 +919,7 @@ LIB_OBJS += merge.o
 LIB_OBJS += merge-blobs.o
 LIB_OBJS += merge-recursive.o
 LIB_OBJS += mergesort.o
+LIB_OBJS += metacommit-parser.o
 LIB_OBJS += midx.o
 LIB_OBJS += name-hash.o
 LIB_OBJS += negotiator/default.o
diff --git a/metacommit-parser.c b/metacommit-parser.c
new file mode 100644
index 0000000000..5013a108a3
--- /dev/null
+++ b/metacommit-parser.c
@@ -0,0 +1,87 @@
+#include "cache.h"
+#include "metacommit-parser.h"
+#include "commit.h"
+
+/*
+ * Search the commit buffer for a line starting with the given key. Unlike
+ * find_commit_header, this also searches the commit message body.
+ */
+static const char *find_key(const char *msg, const char *key, size_t *out_len)
+{
+	int key_len = strlen(key);
+	const char *line = msg;
+
+	while (line) {
+		const char *eol = strchrnul(line, '\n');
+
+		if (eol - line > key_len &&
+				!strncmp(line, key, key_len) &&
+				line[key_len] == ' ') {
+			*out_len = eol - line - key_len - 1;
+			return line + key_len + 1;
+		}
+		line = *eol ? eol + 1 : NULL;
+	}
+	return NULL;
+}
+
+static struct commit *get_commit_by_index(struct commit_list *to_search, int index)
+{
+	while (to_search && index) {
+		to_search = to_search->next;
+		--index;
+	}
+
+	return to_search->item;
+}
+
+/*
+ * Writes the content parent's object id to "content".
+ * Returns the metacommit type. See the METACOMMIT_TYPE_* constants.
+ */
+int get_metacommit_content(
+	struct commit *commit, struct object_id *content)
+{
+	const char *buffer = get_commit_buffer(commit, NULL);
+	size_t parent_types_size;
+	const char *parent_types = find_key(buffer, "parent-type",
+		&parent_types_size);
+	const char *end;
+	int index = 0;
+	int ret;
+	struct commit *content_parent;
+
+	if (!parent_types) {
+		return METACOMMIT_TYPE_NONE;
+	}
+
+	end = &(parent_types[parent_types_size]);
+
+	while (1) {
+		char next = *parent_types;
+		if (next == ' ') {
+			index++;
+		}
+		if (next == 'c') {
+			ret = METACOMMIT_TYPE_NORMAL;
+			break;
+		}
+		if (next == 'a') {
+			ret = METACOMMIT_TYPE_ABANDONED;
+			break;
+		}
+		parent_types++;
+		if (parent_types >= end) {
+			return METACOMMIT_TYPE_NONE;
+		}
+	}
+
+	content_parent = get_commit_by_index(commit->parents, index);
+
+	if (!content_parent) {
+		return METACOMMIT_TYPE_NONE;
+	}
+
+	oidcpy(content, &(content_parent->object.oid));
+	return ret;
+}
diff --git a/metacommit-parser.h b/metacommit-parser.h
new file mode 100644
index 0000000000..e546f5a7e7
--- /dev/null
+++ b/metacommit-parser.h
@@ -0,0 +1,16 @@
+#ifndef METACOMMIT_PARSER_H
+#define METACOMMIT_PARSER_H
+
+// Indicates a normal commit (non-metacommit)
+#define METACOMMIT_TYPE_NONE 0
+// Indicates a metacommit with normal content (non-abandoned)
+#define METACOMMIT_TYPE_NORMAL 1
+// Indicates a metacommit with abandoned content
+#define METACOMMIT_TYPE_ABANDONED 2
+
+struct commit;
+
+extern int get_metacommit_content(
+	struct commit *commit, struct object_id *content);
+
+#endif
-- 
2.20.1.321.g9e740568ce-goog


  parent reply	other threads:[~2019-01-21 22:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-21 22:32 [PATCH 1/8] technical doc: add a design doc for the evolve command sxenos
2019-01-21 22:32 ` [PATCH 2/8] evolve: Implement oid_array_contains_nondestructive sxenos
2019-01-22 19:51   ` Stefan Beller
2019-01-27 19:08     ` Stefan Xenos
2019-01-21 22:32 ` [PATCH 3/8] evlove: Add the metas namespace to ref-filter sxenos
2019-01-21 22:32 ` sxenos [this message]
2019-01-21 22:32 ` [PATCH 5/8] evolve: Add the change-table structure sxenos
2019-01-21 22:32 ` [PATCH 6/8] evolve: Add support for writing metacommits sxenos
2019-01-21 22:32 ` [PATCH 7/8] evolve: Implement the git change update command sxenos
2019-01-21 22:32 ` [PATCH 8/8] evolve: Add the git change list command sxenos

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