From: John Cai <johncai86@xxxxxxxxx>
There are two functions that have very similar logic of finding a header
value. find_commit_header, and find_header. We can conslidate the logic
by introducing a new function find_header_mem, which is equivalent to
find_commit_header except it takes a len parameter that determines how
many bytes will be read. find_commit_header and find_header can then both
call find_header_mem.
This reduces duplicate logic, as the logic for finding header values
can now all live in one place.
Signed-off-by: John Cai <johncai86@xxxxxxxxx>
---
Consolidate find_header logic into one function
This addresses the NEEDSWORK comment in builtin/receive-pack.c:
/**
* NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing
* after dropping "_commit" from its name and possibly moving it out
* of commit.c
**/
There are two functions that have very similar logic of finding a header
value. find_commit_header, and find_header. We can conslidate the logic
by introducing a new function find_header_mem, which is equivalent to
find_commit_header except it takes a len parameter that determines how
many bytes will be read. find_commit_header and find_header can then
both call find_header_mem.
This reduces duplicate logic, as the logic for finding header values can
now all live in one place.
Changes since v4:
* adjust verbiage of NEEDSWORK comment block
Changes since v3:
* added NEEDSWORK block detailing what needs to be done to clean up
find_header_mem
* fixed verbiage in commit message
* adjusted style of an if block (based on Junio's feedback)
Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1125%2Fjohn-cai%2Fjc%2Freplace-find-header-v5
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1125/john-cai/jc/replace-find-header-v5
Pull-Request: https://github.com/git/git/pull/1125
Range-diff vs v4:
1: a7b00022b00 ! 1: 02da3136c43 receive-pack.c: consolidate find header logic
@@ commit.c: struct commit_list **commit_list_append(struct commit *commit,
- while (line) {
+ /*
-+ * NEEDSWORK: Between line[0] and msg[len], there may not be a LF nor NUL
-+ * at all, and strchrnul() will scan beyond the range we were given
-+ * Make this operation safer and abide by the contract to only read up to len.
++ * NEEDSWORK: It's possible for strchrnul() to scan beyond the range
++ * given by len. However, current callers are safe because they compute
++ * len by scanning a NUL-terminated block of memory starting at msg.
++ * Make this function safer by checking if the input is NUL-terminated
++ * or has a NL between line[0] and msg[len].
+ */
+ while (line && line < msg + len) {
const char *eol = strchrnul(line, '\n');
builtin/receive-pack.c | 33 ++++++++++-----------------------
commit.c | 16 ++++++++++++++--
commit.h | 5 +++++
3 files changed, 29 insertions(+), 25 deletions(-)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 9f4a0b816cf..5c2732a0d07 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -581,32 +581,19 @@ static char *prepare_push_cert_nonce(const char *path, timestamp_t stamp)
return strbuf_detach(&buf, NULL);
}
-/*
- * NEEDSWORK: reuse find_commit_header() from jk/commit-author-parsing
- * after dropping "_commit" from its name and possibly moving it out
- * of commit.c
- */
static char *find_header(const char *msg, size_t len, const char *key,
const char **next_line)
{
- int key_len = strlen(key);
- const char *line = msg;
-
- while (line && line < msg + len) {
- const char *eol = strchrnul(line, '\n');
-
- if ((msg + len <= eol) || line == eol)
- return NULL;
- if (line + key_len < eol &&
- !memcmp(line, key, key_len) && line[key_len] == ' ') {
- int offset = key_len + 1;
- if (next_line)
- *next_line = *eol ? eol + 1 : eol;
- return xmemdupz(line + offset, (eol - line) - offset);
- }
- line = *eol ? eol + 1 : NULL;
- }
- return NULL;
+ size_t out_len;
+ const char *val = find_header_mem(msg, len, key, &out_len);
+
+ if (!val)
+ return NULL;
+
+ if (next_line)
+ *next_line = val + out_len + 1;
+
+ return xmemdupz(val, out_len);
}
/*
diff --git a/commit.c b/commit.c
index a348f085b2b..f5224e65de2 100644
--- a/commit.c
+++ b/commit.c
@@ -1631,12 +1631,20 @@ struct commit_list **commit_list_append(struct commit *commit,
return &new_commit->next;
}
-const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
+const char *find_header_mem(const char *msg, size_t len,
+ const char *key, size_t *out_len)
{
int key_len = strlen(key);
const char *line = msg;
- while (line) {
+ /*
+ * NEEDSWORK: It's possible for strchrnul() to scan beyond the range
+ * given by len. However, current callers are safe because they compute
+ * len by scanning a NUL-terminated block of memory starting at msg.
+ * Make this function safer by checking if the input is NUL-terminated
+ * or has a NL between line[0] and msg[len].
+ */
+ while (line && line < msg + len) {
const char *eol = strchrnul(line, '\n');
if (line == eol)
@@ -1653,6 +1661,10 @@ const char *find_commit_header(const char *msg, const char *key, size_t *out_len
return NULL;
}
+const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
+{
+ return find_header_mem(msg, strlen(msg), key, out_len);
+}
/*
* Inspect the given string and determine the true "end" of the log message, in
* order to find where to put a new Signed-off-by trailer. Ignored are
diff --git a/commit.h b/commit.h
index 3ea32766bcb..38cc5426615 100644
--- a/commit.h
+++ b/commit.h
@@ -290,12 +290,17 @@ void free_commit_extra_headers(struct commit_extra_header *extra);
/*
* Search the commit object contents given by "msg" for the header "key".
+ * Reads up to "len" bytes of "msg".
* Returns a pointer to the start of the header contents, or NULL. The length
* of the header, up to the first newline, is returned via out_len.
*
* Note that some headers (like mergetag) may be multi-line. It is the caller's
* responsibility to parse further in this case!
*/
+const char *find_header_mem(const char *msg, size_t len,
+ const char *key,
+ size_t *out_len);
+
const char *find_commit_header(const char *msg, const char *key,
size_t *out_len);
base-commit: c8b2ade48c204690119936ada89cd938c476c5c2
--
gitgitgadget
