Merge git_buf and git_buffer

This makes the git_buf struct that was used internally into an
externally available structure and eliminates the git_buffer.

As part of that, some of the special cases that arose with the
externally used git_buffer were blended into the git_buf, such as
being careful about git_buf objects that may have a NULL ptr and
allowing for bufs with a valid ptr and size but zero asize as a
way of referring to externally owned data.

include/git2/blob.h

@@ -104,17 +104,17 @@ GIT_EXTERN(git_off_t) git_blob_rawsize(const git_blob *blob);
  * CRLF filtering or other types of changes depending on the file
  * attributes set for the blob and the content detected in it.
  *
- * The output is written into a `git_buffer` which the caller must free
- * when done (via `git_buffer_free`).
+ * The output is written into a `git_buf` which the caller must free
+ * when done (via `git_buf_free`).
  *
  * If no filters need to be applied, then the `out` buffer will just be
  * populated with a pointer to the raw content of the blob.  In that case,
  * be careful to *not* free the blob until done with the buffer.  To keep
- * the data detached from the blob, call `git_buffer_resize` on the buffer
+ * the data detached from the blob, call `git_buf_grow` on the buffer
  * with a `want_size` of 0 and the buffer will be reallocated to be
  * detached from the blob.
  *
- * @param out The git_buffer to be filled in
+ * @param out The git_buf to be filled in
  * @param blob Pointer to the blob
  * @param as_path Path used for file attribute lookups, etc.
  * @param check_for_binary_data Should this test if blob content contains
@@ -122,7 +122,7 @@ GIT_EXTERN(git_off_t) git_blob_rawsize(const git_blob *blob);
  * @return 0 on success or an error code
  */
 GIT_EXTERN(int) git_blob_filtered_content(
-	git_buffer *out,
+	git_buf *out,
 	git_blob *blob,
 	const char *as_path,
 	int check_for_binary_data);

include/git2/buffer.h

@@ -4,8 +4,8 @@
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
  */
-#ifndef INCLUDE_git_buffer_h__
-#define INCLUDE_git_buffer_h__
+#ifndef INCLUDE_git_buf_h__
+#define INCLUDE_git_buf_h__
 
 #include "common.h"
 
@@ -25,59 +25,69 @@ GIT_BEGIN_DECL
  * caller and have the caller take responsibility for freeing that memory.
  * This can be awkward if the caller does not have easy access to the same
  * allocation functions that libgit2 is using.  In those cases, libgit2
- * will instead fill in a `git_buffer` and the caller can use
- * `git_buffer_free()` to release it when they are done.
- *
- * * `ptr` refers to the start of the allocated memory.
- * * `size` contains the size of the data in `ptr` that is actually used.
- * * `available` refers to the known total amount of allocated memory. It
- *   may be larger than the `size` actually in use.
- *
- * In a few cases, for uniformity and simplicity, an API may populate a
- * `git_buffer` with data that should *not* be freed (i.e. the lifetime of
- * the data buffer is actually tied to another libgit2 object).  These
- * cases will be clearly documented in the APIs that use the `git_buffer`.
- * In those cases, the `available` field will be set to zero even though
- * the `ptr` and `size` will be valid.
+ * will fill in a `git_buf` and the caller can use `git_buf_free()` to
+ * release it when they are done.
+ *
+ * A `git_buf` may also be used for the caller to pass in a reference to
+ * a block of memory they hold.  In this case, libgit2 will not resize or
+ * free the memory, but will read from it as needed.
+ *
+ * A `git_buf` is a public structure with three fields:
+ *
+ * - `ptr` points to the start of the allocated memory.  If it is NULL,
+ *   then the `git_buf` is considered empty and libgit2 will feel free
+ *   to overwrite it with new data.
+ *
+ * - `size` holds the size (in bytes) of the data that is actually used.
+ *
+ * - `asize` holds the known total amount of allocated memory if the `ptr`
+ *    was allocated by libgit2.  It may be larger than `size`.  If `ptr`
+ *    was not allocated by libgit2 and should not be resized and/or freed,
+ *    then `asize` will be set to zero.
+ *
+ * Some APIs may occasionally do something slightly unusual with a buffer,
+ * such as setting `ptr` to a value that was passed in by the user.  In
+ * those cases, the behavior will be clearly documented by the API.
  */
-typedef struct git_buffer {
+typedef struct {
 	char   *ptr;
-	size_t size;
-	size_t available;
-} git_buffer;
+	size_t asize, size;
+} git_buf;
 
 /**
- * Use to initialize buffer structure when git_buffer is on stack
- */
-#define GIT_BUFFER_INIT { NULL, 0, 0 }
-
-/**
- * Free the memory referred to by the git_buffer.
+ * Free the memory referred to by the git_buf.
  *
- * Note that this does not free the `git_buffer` itself, just the memory
- * pointed to by `buffer->ptr`.  If that memory was not allocated by
- * libgit2 itself, be careful with using this function because it could
- * cause problems.
+ * Note that this does not free the `git_buf` itself, just the memory
+ * pointed to by `buffer->ptr`.  This will not free the memory if it looks
+ * like it was not allocated internally, but it will clear the buffer back
+ * to the empty state.
  *
- * @param buffer The buffer with allocated memory
+ * @param buffer The buffer to deallocate
  */
-GIT_EXTERN(void) git_buffer_free(git_buffer *buffer);
+GIT_EXTERN(void) git_buf_free(git_buf *buffer);
 
 /**
  * Resize the buffer allocation to make more space.
  *
- * This will update `buffer->available` with the new size (which will be
- * at least `want_size` and may be larger).  This may or may not change
- * `buffer->ptr` depending on whether there is an existing allocation and
- * whether that allocation can be increased in place.
+ * This will attempt to grow the buffer to accomodate the target size.
+ *
+ * If the buffer refers to memory that was not allocated by libgit2 (i.e.
+ * the `asize` field is zero), then `ptr` will be replaced with a newly
+ * allocated block of data.  Be careful so that memory allocated by the
+ * caller is not lost.  As a special variant, if you pass `target_size` as
+ * 0 and the memory is not allocated by libgit2, this will allocate a new
+ * buffer of size `size` and copy the external data into it.
+ *
+ * Currently, this will never shrink a buffer, only expand it.
  *
- * Currently, this will never shrink the buffer, only expand it.
+ * If the allocation fails, this will return an error and the buffer will be
+ * marked as invalid for future operations, invaliding the contents.
  *
  * @param buffer The buffer to be resized; may or may not be allocated yet
- * @param want_size The desired available size
- * @return 0 on success, negative error code on allocation failure
+ * @param target_size The desired available size
+ * @return 0 on success, -1 on allocation failure
  */
-GIT_EXTERN(int) git_buffer_resize(git_buffer *buffer, size_t want_size);
+GIT_EXTERN(int) git_buf_grow(git_buf *buffer, size_t target_size);
 
 /**
  * Set buffer to a copy of some raw data.
@@ -85,10 +95,10 @@ GIT_EXTERN(int) git_buffer_resize(git_buffer *buffer, size_t want_size);
  * @param buffer The buffer to set
  * @param data The data to copy into the buffer
  * @param datalen The length of the data to copy into the buffer
- * @return 0 on success, negative error code on allocation failure
+ * @return 0 on success, -1 on allocation failure
  */
-GIT_EXTERN(int) git_buffer_copy(
-	git_buffer *buffer, const void *data, size_t datalen);
+GIT_EXTERN(int) git_buf_set(
+	git_buf *buffer, const void *data, size_t datalen);
 
 GIT_END_DECL
 

include/git2/filter.h

@@ -88,16 +88,17 @@ GIT_EXTERN(int) git_filter_list_load(
 /**
  * Apply filter list to a data buffer.
  *
- * See `git2/buffer.h` for background on `git_buffer` objects.
+ * See `git2/buffer.h` for background on `git_buf` objects.
  *
- * If the `in` buffer refers to data managed by libgit2
- * (i.e. `in->available` is not zero), then it will be overwritten when
- * applying the filters.  If not, then it will be left untouched.
+ * If the `in` buffer holds data allocated by libgit2 (i.e. `in->asize` is
+ * not zero), then it will be overwritten when applying the filters.  If
+ * not, then it will be left untouched.
  *
  * If there are no filters to apply (or `filters` is NULL), then the `out`
- * buffer will reference the `in` buffer data (with `available` set to
- * zero) instead of allocating data.  This keeps allocations to a minimum,
- * but it means you have to be careful about freeing the `in` data.
+ * buffer will reference the `in` buffer data (with `asize` set to zero)
+ * instead of allocating data.  This keeps allocations to a minimum, but
+ * it means you have to be careful about freeing the `in` data since `out`
+ * may be pointing to it!
  *
  * @param out Buffer to store the result of the filtering
  * @param filters A loaded git_filter_list (or NULL)
@@ -105,15 +106,15 @@ GIT_EXTERN(int) git_filter_list_load(
  * @return 0 on success, an error code otherwise
  */
 GIT_EXTERN(int) git_filter_list_apply_to_data(
-	git_buffer *out,
+	git_buf *out,
 	git_filter_list *filters,
-	git_buffer *in);
+	git_buf *in);
 
 /**
  * Apply filter list to the contents of a file on disk
  */
 GIT_EXTERN(int) git_filter_list_apply_to_file(
-	git_buffer *out,
+	git_buf *out,
 	git_filter_list *filters,
 	git_repository *repo,
 	const char *path);
@@ -122,7 +123,7 @@ GIT_EXTERN(int) git_filter_list_apply_to_file(
  * Apply filter list to the contents of a blob
  */
 GIT_EXTERN(int) git_filter_list_apply_to_blob(
-	git_buffer *out,
+	git_buf *out,
 	git_filter_list *filters,
 	git_blob *blob);
 

include/git2/sys/filter.h

@@ -4,8 +4,8 @@
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
  */
-#ifndef INCLUDE_sys_git_config_backend_h__
-#define INCLUDE_sys_git_config_backend_h__
+#ifndef INCLUDE_sys_git_filter_h__
+#define INCLUDE_sys_git_filter_h__
 
 #include "git2/filter.h"
 
@@ -117,19 +117,19 @@ typedef void (*git_filter_shutdown_fn)(git_filter *self);
  * Callback to decide if a given source needs this filter
  */
 typedef int (*git_filter_check_fn)(
-	git_filter        *self,
-	void              **payload, /* points to NULL ptr on entry, may be set */
+	git_filter  *self,
+	void       **payload, /* points to NULL ptr on entry, may be set */
 	const git_filter_source *src,
-	const char        **attr_values);
+	const char **attr_values);
 
 /**
  * Callback to actually perform the data filtering
  */
 typedef int (*git_filter_apply_fn)(
-	git_filter        *self,
-	void              **payload, /* may be read and/or set */
-	git_buffer        *to,
-	const git_buffer  *from,
+	git_filter    *self,
+	void         **payload, /* may be read and/or set */
+	git_buf       *to,
+	const git_buf *from,
 	const git_filter_source *src);
 
 /**

src/blob.c

@@ -111,7 +111,7 @@ static int write_file_filtered(
 	git_filter_list *fl)
 {
 	int error;
-	git_buffer tgt = GIT_BUFFER_INIT;
+	git_buf tgt = GIT_BUF_INIT;
 
 	error = git_filter_list_apply_to_file(&tgt, fl, NULL, full_path);
 
@@ -122,7 +122,7 @@ static int write_file_filtered(
 		error = git_odb_write(oid, odb, tgt.ptr, tgt.size, GIT_OBJ_BLOB);
 	}
 
-	git_buffer_free(&tgt);
+	git_buf_free(&tgt);
 	return error;
 }
 
@@ -329,7 +329,7 @@ int git_blob_is_binary(git_blob *blob)
 }
 
 int git_blob_filtered_content(
-	git_buffer *out,
+	git_buf *out,
 	git_blob *blob,
 	const char *path,
 	int check_for_binary_data)

src/buffer.c

@@ -32,7 +32,8 @@ void git_buf_init(git_buf *buf, size_t initial_size)
 		git_buf_grow(buf, initial_size);
 }
 
-int git_buf_try_grow(git_buf *buf, size_t target_size, bool mark_oom)
+int git_buf_try_grow(
+	git_buf *buf, size_t target_size, bool mark_oom, bool preserve_external)
 {
 	char *new_ptr;
 	size_t new_size;
@@ -40,6 +41,9 @@ int git_buf_try_grow(git_buf *buf, size_t target_size, bool mark_oom)
 	if (buf->ptr == git_buf__oom)
 		return -1;
 
+	if (!target_size)
+		target_size = buf->size;
+
 	if (target_size <= buf->asize)
 		return 0;
 
@@ -67,6 +71,9 @@ int git_buf_try_grow(git_buf *buf, size_t target_size, bool mark_oom)
 		return -1;
 	}
 
+	if (preserve_external && !buf->asize && buf->ptr != NULL && buf->size > 0)
+		memcpy(new_ptr, buf->ptr, min(buf->size, new_size));
+
 	buf->asize = new_size;
 	buf->ptr   = new_ptr;
 
@@ -78,11 +85,16 @@ int git_buf_try_grow(git_buf *buf, size_t target_size, bool mark_oom)
 	return 0;
 }
 
+int git_buf_grow(git_buf *buffer, size_t target_size)
+{
+	return git_buf_try_grow(buffer, target_size, true, true);
+}
+
 void git_buf_free(git_buf *buf)
 {
 	if (!buf) return;
 
-	if (buf->ptr != git_buf__initbuf && buf->ptr != git_buf__oom)
+	if (buf->asize > 0 && buf->ptr != NULL && buf->ptr != git_buf__oom)
 		git__free(buf->ptr);
 
 	git_buf_init(buf, 0);
@@ -91,11 +103,15 @@ void git_buf_free(git_buf *buf)
 void git_buf_clear(git_buf *buf)
 {
 	buf->size = 0;
+
+	if (!buf->ptr)
+		buf->ptr = git_buf__initbuf;
+
 	if (buf->asize > 0)
 		buf->ptr[0] = '\0';
 }
 
-int git_buf_set(git_buf *buf, const char *data, size_t len)
+int git_buf_set(git_buf *buf, const void *data, size_t len)
 {
 	if (len == 0 || data == NULL) {
 		git_buf_clear(buf);
@@ -485,74 +501,3 @@ int git_buf_splice(
 	buf->ptr[buf->size] = '\0';
 	return 0;
 }
-
-/*
- * Public buffers API
- */
-
-void git_buffer_free(git_buffer *buffer)
-{
-	if (!buffer)
-		return;
-
-	if (buffer->ptr != NULL && buffer->available > 0)
-		git__free(buffer->ptr);
-
-	git__memzero(buffer, sizeof(*buffer));
-}
-
-static int git_buffer__resize(
-	git_buffer *buffer, size_t want_size, int preserve_data)
-{
-	int non_allocated_buffer = 0;
-	char *new_ptr;
-
-	assert(buffer);
-
-	/* check if buffer->ptr points to memory owned elsewhere */
-	non_allocated_buffer = (buffer->ptr != NULL && buffer->available == 0);
-
-	if (non_allocated_buffer && !want_size)
-		want_size = buffer->size;
-
-	if (buffer->available >= want_size)
-		return 0;
-
-	if (non_allocated_buffer) {
-		new_ptr = NULL;
-		if (want_size < buffer->size)
-			want_size = buffer->size;
-	} else {
-		new_ptr = buffer->ptr;
-	}
-
-	want_size = (want_size + 7) & ~7; /* round up to multiple of 8 */
-
-	new_ptr = git__realloc(new_ptr, want_size);
-	GITERR_CHECK_ALLOC(new_ptr);
-
-	if (non_allocated_buffer && preserve_data)
-		memcpy(new_ptr, buffer->ptr, buffer->size);
-
-	buffer->ptr       = new_ptr;
-	buffer->available = want_size;
-
-	return 0;
-}
-
-int git_buffer_resize(git_buffer *buffer, size_t want_size)
-{
-	return git_buffer__resize(buffer, want_size, true);
-}
-
-int git_buffer_copy(
-	git_buffer *buffer, const void *data, size_t datalen)
-{
-	if (git_buffer__resize(buffer, datalen + 1, false) < 0)
-		return -1;
-	memcpy(buffer->ptr, data, datalen);
-	buffer->ptr[datalen] = '\0';
-	buffer->size = datalen;
-	return 0;
-}
-

src/buffer.h

@@ -12,16 +12,23 @@
 #include "git2/buffer.h"
 #include <stdarg.h>
 
-typedef struct {
-	char *ptr;
-	size_t asize, size;
-} git_buf;
+/* typedef struct {
+ *  	char   *ptr;
+ *  	size_t asize, size;
+ * } git_buf;
+ */
 
 extern char git_buf__initbuf[];
 extern char git_buf__oom[];
 
+/* Use to initialize buffer structure when git_buf is on stack */
 #define GIT_BUF_INIT { git_buf__initbuf, 0, 0 }
 
+GIT_INLINE(bool) git_buf_is_allocated(const git_buf *buf)
+{
+	return (buf->ptr != NULL && buf->asize > 0);
+}
+
 /**
  * Initialize a git_buf structure.
  *
@@ -33,27 +40,16 @@ extern void git_buf_init(git_buf *buf, size_t initial_size);
 /**
  * Attempt to grow the buffer to hold at least `target_size` bytes.
  *
- * If the allocation fails, this will return an error.  If mark_oom is true,
+ * If the allocation fails, this will return an error.  If `mark_oom` is true,
  * this will mark the buffer as invalid for future operations; if false,
  * existing buffer content will be preserved, but calling code must handle
- * that buffer was not expanded.
- */
-extern int git_buf_try_grow(git_buf *buf, size_t target_size, bool mark_oom);
-
-/**
- * Grow the buffer to hold at least `target_size` bytes.
- *
- * If the allocation fails, this will return an error and the buffer will be
- * marked as invalid for future operations, invaliding contents.
- *
- * @return 0 on success or -1 on failure
+ * that buffer was not expanded.  If `preserve_external` is true, then any
+ * existing data pointed to be `ptr` even if `asize` is zero will be copied
+ * into the newly allocated buffer.
  */
-GIT_INLINE(int) git_buf_grow(git_buf *buf, size_t target_size)
-{
-	return git_buf_try_grow(buf, target_size, true);
-}
+extern int git_buf_try_grow(
+	git_buf *buf, size_t target_size, bool mark_oom, bool preserve_external);
 
-extern void git_buf_free(git_buf *buf);
 extern void git_buf_swap(git_buf *buf_a, git_buf *buf_b);
 extern char *git_buf_detach(git_buf *buf);
 extern void git_buf_attach(git_buf *buf, char *ptr, size_t asize);
@@ -82,7 +78,6 @@ GIT_INLINE(bool) git_buf_oom(const git_buf *buf)
  * return code of these functions and call them in a series then just call
  * git_buf_oom at the end.
  */
-int git_buf_set(git_buf *buf, const char *data, size_t len);
 int git_buf_sets(git_buf *buf, const char *string);
 int git_buf_putc(git_buf *buf, char c);
 int git_buf_put(git_buf *buf, const char *data, size_t len);
@@ -175,30 +170,4 @@ int git_buf_splice(
 	const char *data,
 	size_t nb_to_insert);
 
-
-GIT_INLINE(bool) git_buffer_is_allocated(const git_buffer *buffer)
-{
-	return (buffer->ptr != NULL && buffer->available > 0);
-}
-
-#define GIT_BUF_FROM_BUFFER(buffer) \
-	{ (buffer)->ptr, (buffer)->available, (buffer)->size }
-
-GIT_INLINE(void) git_buf_from_buffer(git_buf *buf, const git_buffer *buffer)
-{
-	buf->ptr   = buffer->ptr;
-	buf->size  = buffer->size;
-	buf->asize = buffer->available;
-}
-
-#define GIT_BUFFER_FROM_BUF(buf) \
-	{ (buf)->ptr, (buf)->size, (buf)->asize }
-
-GIT_INLINE(void) git_buffer_from_buf(git_buffer *buffer, const git_buf *buf)
-{
-	buffer->ptr  = buf->ptr;
-	buffer->size = buf->size;
-	buffer->available = buf->asize;
-}
-
 #endif

src/checkout.c

@@ -678,20 +678,19 @@ fail:
 
 static int buffer_to_file(
 	struct stat *st,
-	git_buffer *buffer,
+	git_buf *buf,
 	const char *path,
 	mode_t dir_mode,
 	int file_open_flags,
 	mode_t file_mode)
 {
 	int error;
-	git_buf buf = GIT_BUF_FROM_BUFFER(buffer);
 
 	if ((error = git_futils_mkpath2file(path, dir_mode)) < 0)
 		return error;
 
 	if ((error = git_futils_writebuffer(
-			&buf, path, file_open_flags, file_mode)) < 0)
+			buf, path, file_open_flags, file_mode)) < 0)
 		return error;
 
 	if (st != NULL && (error = p_stat(path, st)) < 0)
@@ -713,7 +712,7 @@ static int blob_content_to_file(
 {
 	int error = 0;
 	mode_t file_mode = opts->file_mode ? opts->file_mode : entry_filemode;
-	git_buffer out = GIT_BUFFER_INIT;
+	git_buf out = GIT_BUF_INIT;
 	git_filter_list *fl = NULL;
 
 	if (!opts->disable_filters && !git_blob_is_binary(blob))
@@ -731,7 +730,7 @@ static int blob_content_to_file(
 
 		st->st_mode = entry_filemode;
 
-		git_buffer_free(&out);
+		git_buf_free(&out);
 	}
 
 	return error;

src/config_file.c

@@ -293,6 +293,8 @@ static int config_iterator_new(
 	diskfile_backend *b = (diskfile_backend *)backend;
 	git_config_file_iter *it = git__calloc(1, sizeof(git_config_file_iter));
 
+	GIT_UNUSED(b);
+
 	GITERR_CHECK_ALLOC(it);
 
 	it->parent.backend = backend;

src/crlf.c

@@ -119,15 +119,12 @@ static int has_cr_in_index(const git_filter_source *src)
 
 static int crlf_apply_to_odb(
 	struct crlf_attrs *ca,
-	git_buffer *to,
-	const git_buffer *from,
+	git_buf *to,
+	const git_buf *from,
 	const git_filter_source *src)
 {
-	const git_buf from_buf = GIT_BUF_FROM_BUFFER(from);
-	git_buf to_buf = GIT_BUF_FROM_BUFFER(to);
-
 	/* Empty file? Nothing to do */
-	if (!git_buf_len(&from_buf))
+	if (!git_buf_len(from))
 		return 0;
 
 	/* Heuristics to see if we can skip the conversion.
@@ -137,7 +134,7 @@ static int crlf_apply_to_odb(
 		git_buf_text_stats stats;
 
 		/* Check heuristics for binary vs text... */
-		if (git_buf_text_gather_stats(&stats, &from_buf, false))
+		if (git_buf_text_gather_stats(&stats, from, false))
 			return -1;
 
 		/*
@@ -162,13 +159,7 @@ static int crlf_apply_to_odb(
 	}
 
 	/* Actually drop the carriage returns */
-	if (git_buf_text_crlf_to_lf(&to_buf, &from_buf) < 0)
-		return -1;
-
-	/* Overwrite "to" buffer in case data was resized */
-	git_buffer_from_buf(to, &to_buf);
-
-	return 0;
+	return git_buf_text_crlf_to_lf(to, from);
 }
 
 static const char *line_ending(struct crlf_attrs *ca)
@@ -210,14 +201,12 @@ line_ending_error:
 }
 
 static int crlf_apply_to_workdir(
-	struct crlf_attrs *ca, git_buffer *to, const git_buffer *from)
+	struct crlf_attrs *ca, git_buf *to, const git_buf *from)
 {
-	const git_buf from_buf = GIT_BUF_FROM_BUFFER(from);
-	git_buf to_buf = GIT_BUF_FROM_BUFFER(to);
 	const char *workdir_ending = NULL;
 
 	/* Empty file? Nothing to do. */
-	if (git_buf_len(&from_buf) == 0)
+	if (git_buf_len(from) == 0)
 		return 0;
 
 	/* Determine proper line ending */
@@ -229,22 +218,19 @@ static int crlf_apply_to_workdir(
 		if (ca->crlf_action == GIT_CRLF_GUESS && ca->auto_crlf)
 			return GIT_ENOTFOUND;
 
-		if (git_buf_find(&from_buf, '\r') < 0)
+		if (git_buf_find(from, '\r') < 0)
 			return GIT_ENOTFOUND;
 
-		if (git_buf_text_crlf_to_lf(&to_buf, &from_buf) < 0)
+		if (git_buf_text_crlf_to_lf(to, from) < 0)
 			return -1;
 	} else {
 		/* only other supported option is lf->crlf conversion */
 		assert(!strcmp("\r\n", workdir_ending));
 
-		if (git_buf_text_lf_to_crlf(&to_buf, &from_buf) < 0)
+		if (git_buf_text_lf_to_crlf(to, from) < 0)
 			return -1;
 	}
 
-	/* Overwrite "to" buffer in case data was resized */
-	git_buffer_from_buf(to, &to_buf);
-
 	return 0;
 }
 
@@ -297,10 +283,10 @@ static int crlf_check(
 }
 
 static int crlf_apply(
-	git_filter        *self,
-	void              **payload, /* may be read and/or set */
-	git_buffer        *to,
-	const git_buffer  *from,
+	git_filter    *self,
+	void         **payload, /* may be read and/or set */
+	git_buf       *to,
+	const git_buf *from,
 	const git_filter_source *src)
 {
 	/* initialize payload in case `check` was bypassed */

src/diff_file.c

@@ -327,11 +327,11 @@ static int diff_file_content_load_workdir_file(
 	}
 
 	if (!(error = git_futils_readbuffer_fd(&raw, fd, (size_t)fc->file->size))) {
-		git_buffer in = GIT_BUFFER_FROM_BUF(&raw), out = GIT_BUFFER_INIT;
+		git_buf out = GIT_BUF_INIT;
 
-		error = git_filter_list_apply_to_data(&out, fl, &in);
+		error = git_filter_list_apply_to_data(&out, fl, &raw);
 
-		git_buffer_free(&in);
+		git_buf_free(&raw);
 
 		if (!error) {
 			fc->map.len  = out.size;

src/filter.c

@@ -549,23 +549,28 @@ int git_filter_list_push(
 }
 
 static int filter_list_out_buffer_from_raw(
-	git_buffer *out, const void *ptr, size_t size)
+	git_buf *out, const void *ptr, size_t size)
 {
-	if (git_buffer_is_allocated(out))
-		git_buffer_free(out);
+	if (git_buf_is_allocated(out))
+		git_buf_free(out);
+
+	if (!size) {
+		git_buf_init(out, 0);
+	} else {
+		out->ptr   = (char *)ptr;
+		out->asize = 0;
+		out->size  = size;
+	}
 
-	out->ptr  = (char *)ptr;
-	out->size = size;
-	out->available = 0;
 	return 0;
 }
 
 int git_filter_list_apply_to_data(
-	git_buffer *tgt, git_filter_list *fl, git_buffer *src)
+	git_buf *tgt, git_filter_list *fl, git_buf *src)
 {
 	int error = 0;
 	uint32_t i;
-	git_buffer *dbuffer[2], local = GIT_BUFFER_INIT;
+	git_buf *dbuffer[2], local = GIT_BUF_INIT;
 	unsigned int si = 0;
 
 	if (!fl)
@@ -575,8 +580,8 @@ int git_filter_list_apply_to_data(
 	dbuffer[1] = tgt;
 
 	/* if `src` buffer is reallocable, then use it, otherwise copy it */
-	if (!git_buffer_is_allocated(src)) {
-		if (git_buffer_copy(&local, src->ptr, src->size) < 0)
+	if (!git_buf_is_allocated(src)) {
+		if (git_buf_set(&local, src->ptr, src->size) < 0)
 			return -1;
 		dbuffer[0] = &local;
 	}
@@ -610,19 +615,16 @@ int git_filter_list_apply_to_data(
 	}
 
 	/* Ensure that the output ends up in dbuffer[1] (i.e. the dest) */
-	if (si != 1) {
-		git_buffer sw = *dbuffer[1];
-		*dbuffer[1] = *dbuffer[0];
-		*dbuffer[0] = sw;
-	}
+	if (si != 1)
+		git_buf_swap(dbuffer[0], dbuffer[1]);
 
-	git_buffer_free(&local); /* don't leak if we allocated locally */
+	git_buf_free(&local); /* don't leak if we allocated locally */
 
 	return 0;
 }
 
 int git_filter_list_apply_to_file(
-	git_buffer *out,
+	git_buf *out,
 	git_filter_list *filters,
 	git_repository *repo,
 	const char *path)
@@ -634,11 +636,9 @@ int git_filter_list_apply_to_file(
 	if (!(error = git_path_join_unrooted(&abspath, path, base, NULL)) &&
 		!(error = git_futils_readbuffer(&raw, abspath.ptr)))
 	{
-		git_buffer in = GIT_BUFFER_FROM_BUF(&raw);
-
-		error = git_filter_list_apply_to_data(out, filters, &in);
+		error = git_filter_list_apply_to_data(out, filters, &raw);
 
-		git_buffer_free(&in);
+		git_buf_free(&raw);
 	}
 
 	git_buf_free(&abspath);
@@ -646,12 +646,12 @@ int git_filter_list_apply_to_file(
 }
 
 int git_filter_list_apply_to_blob(
-	git_buffer *out,
+	git_buf *out,
 	git_filter_list *filters,
 	git_blob *blob)
 {
-	git_buffer in = {
-		(char *)git_blob_rawcontent(blob), git_blob_rawsize(blob), 0
+	git_buf in = {
+		(char *)git_blob_rawcontent(blob), 0, git_blob_rawsize(blob)
 	};
 
 	if (filters)

src/ident.c

@@ -9,7 +9,7 @@
 #include "filter.h"
 #include "buffer.h"
 
-int ident_find_id(
+static int ident_find_id(
 	const char **id_start, const char **id_end, const char *start, size_t len)
 {
 	const char *found;
@@ -36,12 +36,11 @@ int ident_find_id(
 }
 
 static int ident_insert_id(
-	git_buffer *to, const git_buffer *from, const git_filter_source *src)
+	git_buf *to, const git_buf *from, const git_filter_source *src)
 {
 	char oid[GIT_OID_HEXSZ+1];
 	const char *id_start, *id_end, *from_end = from->ptr + from->size;
 	size_t need_size;
-	git_buf to_buf = GIT_BUF_FROM_BUFFER(to);
 
 	/* replace $Id$ with blob id */
 
@@ -57,28 +56,23 @@ static int ident_insert_id(
 		5 /* "$Id: " */ + GIT_OID_HEXSZ + 1 /* "$" */ +
 		(size_t)(from_end - id_end);
 
-	if (git_buf_grow(&to_buf, need_size) < 0)
+	if (git_buf_grow(to, need_size) < 0)
 		return -1;
 
-	git_buf_set(&to_buf, from->ptr, (size_t)(id_start - from->ptr));
-	git_buf_put(&to_buf, "$Id: ", 5);
-	git_buf_put(&to_buf, oid, GIT_OID_HEXSZ);
-	git_buf_putc(&to_buf, '$');
-	git_buf_put(&to_buf, id_end, (size_t)(from_end - id_end));
+	git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
+	git_buf_put(to, "$Id: ", 5);
+	git_buf_put(to, oid, GIT_OID_HEXSZ);
+	git_buf_putc(to, '$');
+	git_buf_put(to, id_end, (size_t)(from_end - id_end));
 
-	if (git_buf_oom(&to_buf))
-		return -1;
-
-	git_buffer_from_buf(to, &to_buf);
-	return 0;
+	return git_buf_oom(to) ? -1 : 0;
 }
 
 static int ident_remove_id(
-	git_buffer *to, const git_buffer *from)
+	git_buf *to, const git_buf *from)
 {
 	const char *id_start, *id_end, *from_end = from->ptr + from->size;
 	size_t need_size;
-	git_buf to_buf = GIT_BUF_FROM_BUFFER(to);
 
 	if (ident_find_id(&id_start, &id_end, from->ptr, from->size) < 0)
 		return GIT_ENOTFOUND;
@@ -86,25 +80,21 @@ static int ident_remove_id(
 	need_size = (size_t)(id_start - from->ptr) +
 		4 /* "$Id$" */ + (size_t)(from_end - id_end);
 
-	if (git_buf_grow(&to_buf, need_size) < 0)
+	if (git_buf_grow(to, need_size) < 0)
 		return -1;
 
-	git_buf_set(&to_buf, from->ptr, (size_t)(id_start - from->ptr));
-	git_buf_put(&to_buf, "$Id$", 4);
-	git_buf_put(&to_buf, id_end, (size_t)(from_end - id_end));
+	git_buf_set(to, from->ptr, (size_t)(id_start - from->ptr));
+	git_buf_put(to, "$Id$", 4);
+	git_buf_put(to, id_end, (size_t)(from_end - id_end));
 
-	if (git_buf_oom(&to_buf))
-		return -1;
-
-	git_buffer_from_buf(to, &to_buf);
-	return 0;
+	return git_buf_oom(to) ? -1 : 0;
 }
 
 static int ident_apply(
-	git_filter        *self,
-	void              **payload,
-	git_buffer        *to,
-	const git_buffer  *from,
+	git_filter     *self,
+	void          **payload,
+	git_buf        *to,
+	const git_buf  *from,
 	const git_filter_source *src)
 {
 	GIT_UNUSED(self); GIT_UNUSED(payload);

src/odb.c

@@ -192,16 +192,16 @@ int git_odb__hashfd_filtered(
 	 */
 
 	if (!(error = git_futils_readbuffer_fd(&raw, fd, size))) {
-		git_buffer pre = GIT_BUFFER_FROM_BUF(&raw), post = GIT_BUFFER_INIT;
+		git_buf post = GIT_BUF_INIT;
 
-		error = git_filter_list_apply_to_data(&post, fl, &pre);
+		error = git_filter_list_apply_to_data(&post, fl, &raw);
 
-		git_buffer_free(&pre);
+		git_buf_free(&raw);
 
 		if (!error)
 			error = git_odb_hash(out, post.ptr, post.size, type);
 
-		git_buffer_free(&post);
+		git_buf_free(&post);
 	}
 
 	return error;

src/path.c

@@ -565,7 +565,7 @@ static bool _check_dir_contents(
 	size_t sub_size = strlen(sub);
 
 	/* leave base valid even if we could not make space for subdir */
-	if (git_buf_try_grow(dir, dir_size + sub_size + 2, false) < 0)
+	if (git_buf_try_grow(dir, dir_size + sub_size + 2, false, false) < 0)
 		return false;
 
 	/* save excursion */

src/util.c

@@ -679,6 +679,9 @@ size_t git__unescape(char *str)
 {
 	char *scan, *pos = str;
 
+	if (!str)
+		return 0;
+
 	for (scan = str; *scan; pos++, scan++) {
 		if (*scan == '\\' && *(scan + 1) != '\0')
 			scan++; /* skip '\' but include next char */

tests-clar/filter/blob.c

@@ -23,7 +23,7 @@ void test_filter_blob__cleanup(void)
 void test_filter_blob__all_crlf(void)
 {
 	git_blob *blob;
-	git_buffer buf = GIT_BUFFER_INIT;
+	git_buf buf = { 0 };
 
 	cl_git_pass(git_revparse_single(
 		(git_object **)&blob, g_repo, "a9a2e891")); /* all-crlf */
@@ -43,7 +43,7 @@ void test_filter_blob__all_crlf(void)
 
 	cl_assert_equal_s(ALL_CRLF_TEXT_AS_LF, buf.ptr);
 
-	git_buffer_free(&buf);
+	git_buf_free(&buf);
 	git_blob_free(blob);
 }
 
@@ -51,7 +51,7 @@ void test_filter_blob__ident(void)
 {
 	git_oid id;
 	git_blob *blob;
-	git_buffer buf = GIT_BUFFER_INIT;
+	git_buf buf = { 0 };
 
 	cl_git_mkfile("crlf/test.ident", "Some text\n$Id$\nGoes there\n");
 	cl_git_pass(git_blob_create_fromworkdir(&id, g_repo, "test.ident"));
@@ -78,4 +78,7 @@ void test_filter_blob__ident(void)
 	cl_assert_equal_s(
 		"Some text\n$Id: 3164f585d548ac68027d22b104f2d8100b2b6845$\nGoes there\n", buf.ptr);
 
+	git_buf_free(&buf);
+	git_blob_free(blob);
+
 }

tests-clar/filter/crlf.c

@@ -20,7 +20,7 @@ void test_filter_crlf__to_worktree(void)
 {
 	git_filter_list *fl;
 	git_filter *crlf;
-	git_buffer in = GIT_BUFFER_INIT, out = GIT_BUFFER_INIT;
+	git_buf in = { 0 }, out = { 0 };
 
 	{
 		git_config *cfg;
@@ -48,14 +48,14 @@ void test_filter_crlf__to_worktree(void)
 #endif
 
 	git_filter_list_free(fl);
-	git_buffer_free(&out);
+	git_buf_free(&out);
 }
 
 void test_filter_crlf__to_odb(void)
 {
 	git_filter_list *fl;
 	git_filter *crlf;
-	git_buffer in = GIT_BUFFER_INIT, out = GIT_BUFFER_INIT;
+	git_buf in = { 0 }, out = { 0 };
 
 	{
 		git_config *cfg;
@@ -79,5 +79,5 @@ void test_filter_crlf__to_odb(void)
 	cl_assert_equal_s("Some text\nRight here\n", out.ptr);
 
 	git_filter_list_free(fl);
-	git_buffer_free(&out);
+	git_buf_free(&out);
 }

tests-clar/filter/ident.c

@@ -20,7 +20,7 @@ static void add_blob_and_filter(
 {
 	git_oid id;
 	git_blob *blob;
-	git_buffer out = GIT_BUFFER_INIT;
+	git_buf out = { 0 };
 
 	cl_git_mkfile("crlf/identtest", data);
 	cl_git_pass(git_blob_create_fromworkdir(&id, g_repo, "identtest"));
@@ -31,7 +31,7 @@ static void add_blob_and_filter(
 	cl_assert_equal_s(expected, out.ptr);
 
 	git_blob_free(blob);
-	git_buffer_free(&out);
+	git_buf_free(&out);
 }
 
 void test_filter_ident__to_worktree(void)

tests-clar/object/blob/filter.c

@@ -104,7 +104,7 @@ void test_object_blob_filter__to_odb(void)
 	git_config *cfg;
 	int i;
 	git_blob *blob;
-	git_buffer out = GIT_BUFFER_INIT;
+	git_buf out = GIT_BUF_INIT;
 
 	cl_git_pass(git_repository_config(&cfg, g_repo));
 	cl_assert(cfg);
@@ -129,7 +129,7 @@ void test_object_blob_filter__to_odb(void)
 	}
 
 	git_filter_list_free(fl);
-	git_buffer_free(&out);
+	git_buf_free(&out);
 	git_config_free(cfg);
 }