Adding upstream version 1.7.2+ds.upstream/1.7.2+ds

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1477 insertions, 0 deletions

diff --git a/include/git2/diff.h b/include/git2/diff.h
new file mode 100644
index 0000000..384b6e7
--- /dev/null
+++ b/include/git2/diff.h
@@ -0,0 +1,1477 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * 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_diff_h__
+#define INCLUDE_git_diff_h__
+
+#include "common.h"
+#include "types.h"
+#include "oid.h"
+#include "tree.h"
+#include "refs.h"
+
+/**
+ * @file git2/diff.h
+ * @brief Git tree and file differencing routines.
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Flags for diff options.  A combination of these flags can be passed
+ * in via the `flags` value in the `git_diff_options`.
+ */
+typedef enum {
+	/** Normal diff, the default */
+	GIT_DIFF_NORMAL = 0,
+
+	/*
+	 * Options controlling which files will be in the diff
+	 */
+
+	/** Reverse the sides of the diff */
+	GIT_DIFF_REVERSE = (1u << 0),
+
+	/** Include ignored files in the diff */
+	GIT_DIFF_INCLUDE_IGNORED = (1u << 1),
+
+	/** Even with GIT_DIFF_INCLUDE_IGNORED, an entire ignored directory
+	 *  will be marked with only a single entry in the diff; this flag
+	 *  adds all files under the directory as IGNORED entries, too.
+	 */
+	GIT_DIFF_RECURSE_IGNORED_DIRS = (1u << 2),
+
+	/** Include untracked files in the diff */
+	GIT_DIFF_INCLUDE_UNTRACKED = (1u << 3),
+
+	/** Even with GIT_DIFF_INCLUDE_UNTRACKED, an entire untracked
+	 *  directory will be marked with only a single entry in the diff
+	 *  (a la what core Git does in `git status`); this flag adds *all*
+	 *  files under untracked directories as UNTRACKED entries, too.
+	 */
+	GIT_DIFF_RECURSE_UNTRACKED_DIRS = (1u << 4),
+
+	/** Include unmodified files in the diff */
+	GIT_DIFF_INCLUDE_UNMODIFIED = (1u << 5),
+
+	/** Normally, a type change between files will be converted into a
+	 *  DELETED record for the old and an ADDED record for the new; this
+	 *  options enabled the generation of TYPECHANGE delta records.
+	 */
+	GIT_DIFF_INCLUDE_TYPECHANGE = (1u << 6),
+
+	/** Even with GIT_DIFF_INCLUDE_TYPECHANGE, blob->tree changes still
+	 *  generally show as a DELETED blob.  This flag tries to correctly
+	 *  label blob->tree transitions as TYPECHANGE records with new_file's
+	 *  mode set to tree.  Note: the tree SHA will not be available.
+	 */
+	GIT_DIFF_INCLUDE_TYPECHANGE_TREES = (1u << 7),
+
+	/** Ignore file mode changes */
+	GIT_DIFF_IGNORE_FILEMODE = (1u << 8),
+
+	/** Treat all submodules as unmodified */
+	GIT_DIFF_IGNORE_SUBMODULES = (1u << 9),
+
+	/** Use case insensitive filename comparisons */
+	GIT_DIFF_IGNORE_CASE = (1u << 10),
+
+	/** May be combined with `GIT_DIFF_IGNORE_CASE` to specify that a file
+	 *  that has changed case will be returned as an add/delete pair.
+	 */
+	GIT_DIFF_INCLUDE_CASECHANGE = (1u << 11),
+
+	/** If the pathspec is set in the diff options, this flags indicates
+	 *  that the paths will be treated as literal paths instead of
+	 *  fnmatch patterns.  Each path in the list must either be a full
+	 *  path to a file or a directory.  (A trailing slash indicates that
+	 *  the path will _only_ match a directory).  If a directory is
+	 *  specified, all children will be included.
+	 */
+	GIT_DIFF_DISABLE_PATHSPEC_MATCH = (1u << 12),
+
+	/** Disable updating of the `binary` flag in delta records.  This is
+	 *  useful when iterating over a diff if you don't need hunk and data
+	 *  callbacks and want to avoid having to load file completely.
+	 */
+	GIT_DIFF_SKIP_BINARY_CHECK = (1u << 13),
+
+	/** When diff finds an untracked directory, to match the behavior of
+	 *  core Git, it scans the contents for IGNORED and UNTRACKED files.
+	 *  If *all* contents are IGNORED, then the directory is IGNORED; if
+	 *  any contents are not IGNORED, then the directory is UNTRACKED.
+	 *  This is extra work that may not matter in many cases.  This flag
+	 *  turns off that scan and immediately labels an untracked directory
+	 *  as UNTRACKED (changing the behavior to not match core Git).
+	 */
+	GIT_DIFF_ENABLE_FAST_UNTRACKED_DIRS = (1u << 14),
+
+	/** When diff finds a file in the working directory with stat
+	 * information different from the index, but the OID ends up being the
+	 * same, write the correct stat information into the index.  Note:
+	 * without this flag, diff will always leave the index untouched.
+	 */
+	GIT_DIFF_UPDATE_INDEX = (1u << 15),
+
+	/** Include unreadable files in the diff */
+	GIT_DIFF_INCLUDE_UNREADABLE = (1u << 16),
+
+	/** Include unreadable files in the diff */
+	GIT_DIFF_INCLUDE_UNREADABLE_AS_UNTRACKED = (1u << 17),
+
+	/*
+	 * Options controlling how output will be generated
+	 */
+
+	/** Use a heuristic that takes indentation and whitespace into account
+	 * which generally can produce better diffs when dealing with ambiguous
+	 * diff hunks.
+	 */
+	GIT_DIFF_INDENT_HEURISTIC = (1u << 18),
+
+	/** Ignore blank lines */
+	GIT_DIFF_IGNORE_BLANK_LINES = (1u << 19),
+
+	/** Treat all files as text, disabling binary attributes & detection */
+	GIT_DIFF_FORCE_TEXT = (1u << 20),
+	/** Treat all files as binary, disabling text diffs */
+	GIT_DIFF_FORCE_BINARY = (1u << 21),
+
+	/** Ignore all whitespace */
+	GIT_DIFF_IGNORE_WHITESPACE = (1u << 22),
+	/** Ignore changes in amount of whitespace */
+	GIT_DIFF_IGNORE_WHITESPACE_CHANGE = (1u << 23),
+	/** Ignore whitespace at end of line */
+	GIT_DIFF_IGNORE_WHITESPACE_EOL = (1u << 24),
+
+	/** When generating patch text, include the content of untracked
+	 *  files.  This automatically turns on GIT_DIFF_INCLUDE_UNTRACKED but
+	 *  it does not turn on GIT_DIFF_RECURSE_UNTRACKED_DIRS.  Add that
+	 *  flag if you want the content of every single UNTRACKED file.
+	 */
+	GIT_DIFF_SHOW_UNTRACKED_CONTENT = (1u << 25),
+
+	/** When generating output, include the names of unmodified files if
+	 *  they are included in the git_diff.  Normally these are skipped in
+	 *  the formats that list files (e.g. name-only, name-status, raw).
+	 *  Even with this, these will not be included in patch format.
+	 */
+	GIT_DIFF_SHOW_UNMODIFIED = (1u << 26),
+
+	/** Use the "patience diff" algorithm */
+	GIT_DIFF_PATIENCE = (1u << 28),
+	/** Take extra time to find minimal diff */
+	GIT_DIFF_MINIMAL = (1u << 29),
+
+	/** Include the necessary deflate / delta information so that `git-apply`
+	 *  can apply given diff information to binary files.
+	 */
+	GIT_DIFF_SHOW_BINARY = (1u << 30)
+} git_diff_option_t;
+
+/**
+ * The diff object that contains all individual file deltas.
+ *
+ * A `diff` represents the cumulative list of differences between two
+ * snapshots of a repository (possibly filtered by a set of file name
+ * patterns).
+ *
+ * Calculating diffs is generally done in two phases: building a list of
+ * diffs then traversing it. This makes is easier to share logic across
+ * the various types of diffs (tree vs tree, workdir vs index, etc.), and
+ * also allows you to insert optional diff post-processing phases,
+ * such as rename detection, in between the steps. When you are done with
+ * a diff object, it must be freed.
+ *
+ * This is an opaque structure which will be allocated by one of the diff
+ * generator functions below (such as `git_diff_tree_to_tree`). You are
+ * responsible for releasing the object memory when done, using the
+ * `git_diff_free()` function.
+ *
+ */
+typedef struct git_diff git_diff;
+
+/**
+ * Flags for the delta object and the file objects on each side.
+ *
+ * These flags are used for both the `flags` value of the `git_diff_delta`
+ * and the flags for the `git_diff_file` objects representing the old and
+ * new sides of the delta.  Values outside of this public range should be
+ * considered reserved for internal or future use.
+ */
+typedef enum {
+	GIT_DIFF_FLAG_BINARY     = (1u << 0), /**< file(s) treated as binary data */
+	GIT_DIFF_FLAG_NOT_BINARY = (1u << 1), /**< file(s) treated as text data */
+	GIT_DIFF_FLAG_VALID_ID   = (1u << 2), /**< `id` value is known correct */
+	GIT_DIFF_FLAG_EXISTS     = (1u << 3), /**< file exists at this side of the delta */
+	GIT_DIFF_FLAG_VALID_SIZE = (1u << 4)  /**< file size value is known correct */
+} git_diff_flag_t;
+
+/**
+ * What type of change is described by a git_diff_delta?
+ *
+ * `GIT_DELTA_RENAMED` and `GIT_DELTA_COPIED` will only show up if you run
+ * `git_diff_find_similar()` on the diff object.
+ *
+ * `GIT_DELTA_TYPECHANGE` only shows up given `GIT_DIFF_INCLUDE_TYPECHANGE`
+ * in the option flags (otherwise type changes will be split into ADDED /
+ * DELETED pairs).
+ */
+typedef enum {
+	GIT_DELTA_UNMODIFIED = 0,  /**< no changes */
+	GIT_DELTA_ADDED = 1,	   /**< entry does not exist in old version */
+	GIT_DELTA_DELETED = 2,	   /**< entry does not exist in new version */
+	GIT_DELTA_MODIFIED = 3,    /**< entry content changed between old and new */
+	GIT_DELTA_RENAMED = 4,     /**< entry was renamed between old and new */
+	GIT_DELTA_COPIED = 5,      /**< entry was copied from another old entry */
+	GIT_DELTA_IGNORED = 6,     /**< entry is ignored item in workdir */
+	GIT_DELTA_UNTRACKED = 7,   /**< entry is untracked item in workdir */
+	GIT_DELTA_TYPECHANGE = 8,  /**< type of entry changed between old and new */
+	GIT_DELTA_UNREADABLE = 9,  /**< entry is unreadable */
+	GIT_DELTA_CONFLICTED = 10  /**< entry in the index is conflicted */
+} git_delta_t;
+
+/**
+ * Description of one side of a delta.
+ *
+ * Although this is called a "file", it could represent a file, a symbolic
+ * link, a submodule commit id, or even a tree (although that only if you
+ * are tracking type changes or ignored/untracked directories).
+ */
+typedef struct {
+	/**
+	 * The `git_oid` of the item.  If the entry represents an
+	 * absent side of a diff (e.g. the `old_file` of a `GIT_DELTA_ADDED` delta),
+	 * then the oid will be zeroes.
+	 */
+	git_oid            id;
+
+	/**
+	 * The NUL-terminated path to the entry relative to the working
+	 * directory of the repository.
+	 */
+	const char        *path;
+
+	/**
+	 * The size of the entry in bytes.
+	 */
+	git_object_size_t  size;
+
+	/**
+	 * A combination of the `git_diff_flag_t` types
+	 */
+	uint32_t           flags;
+
+	/**
+	 * Roughly, the stat() `st_mode` value for the item.  This will
+	 * be restricted to one of the `git_filemode_t` values.
+	 */
+	uint16_t           mode;
+
+	/**
+	 * Represents the known length of the `id` field, when
+	 * converted to a hex string.  It is generally `GIT_OID_SHA1_HEXSIZE`, unless this
+	 * delta was created from reading a patch file, in which case it may be
+	 * abbreviated to something reasonable, like 7 characters.
+	 */
+	uint16_t           id_abbrev;
+} git_diff_file;
+
+/**
+ * Description of changes to one entry.
+ *
+ * A `delta` is a file pair with an old and new revision.  The old version
+ * may be absent if the file was just created and the new version may be
+ * absent if the file was deleted.  A diff is mostly just a list of deltas.
+ *
+ * When iterating over a diff, this will be passed to most callbacks and
+ * you can use the contents to understand exactly what has changed.
+ *
+ * The `old_file` represents the "from" side of the diff and the `new_file`
+ * represents to "to" side of the diff.  What those means depend on the
+ * function that was used to generate the diff and will be documented below.
+ * You can also use the `GIT_DIFF_REVERSE` flag to flip it around.
+ *
+ * Although the two sides of the delta are named "old_file" and "new_file",
+ * they actually may correspond to entries that represent a file, a symbolic
+ * link, a submodule commit id, or even a tree (if you are tracking type
+ * changes or ignored/untracked directories).
+ *
+ * Under some circumstances, in the name of efficiency, not all fields will
+ * be filled in, but we generally try to fill in as much as possible.  One
+ * example is that the "flags" field may not have either the `BINARY` or the
+ * `NOT_BINARY` flag set to avoid examining file contents if you do not pass
+ * in hunk and/or line callbacks to the diff foreach iteration function.  It
+ * will just use the git attributes for those files.
+ *
+ * The similarity score is zero unless you call `git_diff_find_similar()`
+ * which does a similarity analysis of files in the diff.  Use that
+ * function to do rename and copy detection, and to split heavily modified
+ * files in add/delete pairs.  After that call, deltas with a status of
+ * GIT_DELTA_RENAMED or GIT_DELTA_COPIED will have a similarity score
+ * between 0 and 100 indicating how similar the old and new sides are.
+ *
+ * If you ask `git_diff_find_similar` to find heavily modified files to
+ * break, but to not *actually* break the records, then GIT_DELTA_MODIFIED
+ * records may have a non-zero similarity score if the self-similarity is
+ * below the split threshold.  To display this value like core Git, invert
+ * the score (a la `printf("M%03d", 100 - delta->similarity)`).
+ */
+typedef struct {
+	git_delta_t   status;
+	uint32_t      flags;	   /**< git_diff_flag_t values */
+	uint16_t      similarity;  /**< for RENAMED and COPIED, value 0-100 */
+	uint16_t      nfiles;	   /**< number of files in this delta */
+	git_diff_file old_file;
+	git_diff_file new_file;
+} git_diff_delta;
+
+/**
+ * Diff notification callback function.
+ *
+ * The callback will be called for each file, just before the `git_diff_delta`
+ * gets inserted into the diff.
+ *
+ * When the callback:
+ * - returns < 0, the diff process will be aborted.
+ * - returns > 0, the delta will not be inserted into the diff, but the
+ *		diff process continues.
+ * - returns 0, the delta is inserted into the diff, and the diff process
+ *		continues.
+ */
+typedef int GIT_CALLBACK(git_diff_notify_cb)(
+	const git_diff *diff_so_far,
+	const git_diff_delta *delta_to_add,
+	const char *matched_pathspec,
+	void *payload);
+
+/**
+ * Diff progress callback.
+ *
+ * Called before each file comparison.
+ *
+ * @param diff_so_far The diff being generated.
+ * @param old_path The path to the old file or NULL.
+ * @param new_path The path to the new file or NULL.
+ * @return Non-zero to abort the diff.
+ */
+typedef int GIT_CALLBACK(git_diff_progress_cb)(
+	const git_diff *diff_so_far,
+	const char *old_path,
+	const char *new_path,
+	void *payload);
+
+/**
+ * Structure describing options about how the diff should be executed.
+ *
+ * Setting all values of the structure to zero will yield the default
+ * values.  Similarly, passing NULL for the options structure will
+ * give the defaults.  The default values are marked below.
+ *
+ */
+typedef struct {
+	unsigned int version;      /**< version for the struct */
+
+	/**
+	 * A combination of `git_diff_option_t` values above.
+	 * Defaults to GIT_DIFF_NORMAL
+	 */
+	uint32_t flags;
+
+	/* options controlling which files are in the diff */
+
+	/** Overrides the submodule ignore setting for all submodules in the diff. */
+	git_submodule_ignore_t ignore_submodules;
+
+	/**
+	 * An array of paths / fnmatch patterns to constrain diff.
+	 * All paths are included by default.
+	 */
+	git_strarray       pathspec;
+
+	/**
+	 * An optional callback function, notifying the consumer of changes to
+	 * the diff as new deltas are added.
+	 */
+	git_diff_notify_cb   notify_cb;
+
+	/**
+	 * An optional callback function, notifying the consumer of which files
+	 * are being examined as the diff is generated.
+	 */
+	git_diff_progress_cb progress_cb;
+
+	/** The payload to pass to the callback functions. */
+	void                *payload;
+
+	/* options controlling how to diff text is generated */
+
+	/**
+	 * The number of unchanged lines that define the boundary of a hunk
+	 * (and to display before and after). Defaults to 3.
+	 */
+	uint32_t    context_lines;
+	/**
+	 * The maximum number of unchanged lines between hunk boundaries before
+	 * the hunks will be merged into one. Defaults to 0.
+	 */
+	uint32_t    interhunk_lines;
+
+	/**
+	 * The object ID type to emit in diffs; this is used by functions
+	 * that operate without a repository - namely `git_diff_buffers`,
+	 * or `git_diff_blobs` and `git_diff_blob_to_buffer` when one blob
+	 * is `NULL`.
+	 *
+	 * This may be omitted (set to `0`). If a repository is available,
+	 * the object ID format of the repository will be used. If no
+	 * repository is available then the default is `GIT_OID_SHA`.
+	 *
+	 * If this is specified and a repository is available, then the
+	 * specified `oid_type` must match the repository's object ID
+	 * format.
+	 */
+	git_oid_t   oid_type;
+
+	/**
+	 * The abbreviation length to use when formatting object ids.
+	 * Defaults to the value of 'core.abbrev' from the config, or 7 if unset.
+	 */
+	uint16_t    id_abbrev;
+
+	/**
+	 * A size (in bytes) above which a blob will be marked as binary
+	 * automatically; pass a negative value to disable.
+	 * Defaults to 512MB.
+	 */
+	git_off_t   max_size;
+
+	/**
+	 * The virtual "directory" prefix for old file names in hunk headers.
+	 * Default is "a".
+	 */
+	const char *old_prefix;
+
+	/**
+	 * The virtual "directory" prefix for new file names in hunk headers.
+	 * Defaults to "b".
+	 */
+	const char *new_prefix;
+} git_diff_options;
+
+/* The current version of the diff options structure */
+#define GIT_DIFF_OPTIONS_VERSION 1
+
+/* Stack initializer for diff options.  Alternatively use
+ * `git_diff_options_init` programmatic initialization.
+ */
+#define GIT_DIFF_OPTIONS_INIT \
+	{GIT_DIFF_OPTIONS_VERSION, 0, GIT_SUBMODULE_IGNORE_UNSPECIFIED, {NULL,0}, NULL, NULL, NULL, 3}
+
+/**
+ * Initialize git_diff_options structure
+ *
+ * Initializes a `git_diff_options` with default values. Equivalent to creating
+ * an instance with GIT_DIFF_OPTIONS_INIT.
+ *
+ * @param opts The `git_diff_options` struct to initialize.
+ * @param version The struct version; pass `GIT_DIFF_OPTIONS_VERSION`.
+ * @return Zero on success; -1 on failure.
+ */
+GIT_EXTERN(int) git_diff_options_init(
+	git_diff_options *opts,
+	unsigned int version);
+
+/**
+ * When iterating over a diff, callback that will be made per file.
+ *
+ * @param delta A pointer to the delta data for the file
+ * @param progress Goes from 0 to 1 over the diff
+ * @param payload User-specified pointer from foreach function
+ */
+typedef int GIT_CALLBACK(git_diff_file_cb)(
+	const git_diff_delta *delta,
+	float progress,
+	void *payload);
+
+#define GIT_DIFF_HUNK_HEADER_SIZE	128
+
+/**
+ * When producing a binary diff, the binary data returned will be
+ * either the deflated full ("literal") contents of the file, or
+ * the deflated binary delta between the two sides (whichever is
+ * smaller).
+ */
+typedef enum {
+	/** There is no binary delta. */
+	GIT_DIFF_BINARY_NONE,
+
+	/** The binary data is the literal contents of the file. */
+	GIT_DIFF_BINARY_LITERAL,
+
+	/** The binary data is the delta from one side to the other. */
+	GIT_DIFF_BINARY_DELTA
+} git_diff_binary_t;
+
+/** The contents of one of the files in a binary diff. */
+typedef struct {
+	/** The type of binary data for this file. */
+	git_diff_binary_t type;
+
+	/** The binary data, deflated. */
+	const char *data;
+
+	/** The length of the binary data. */
+	size_t datalen;
+
+	/** The length of the binary data after inflation. */
+	size_t inflatedlen;
+} git_diff_binary_file;
+
+/**
+ * Structure describing the binary contents of a diff.
+ *
+ * A `binary` file / delta is a file (or pair) for which no text diffs
+ * should be generated. A diff can contain delta entries that are
+ * binary, but no diff content will be output for those files. There is
+ * a base heuristic for binary detection and you can further tune the
+ * behavior with git attributes or diff flags and option settings.
+ */
+typedef struct {
+	/**
+	 * Whether there is data in this binary structure or not.
+	 *
+	 * If this is `1`, then this was produced and included binary content.
+	 * If this is `0` then this was generated knowing only that a binary
+	 * file changed but without providing the data, probably from a patch
+	 * that said `Binary files a/file.txt and b/file.txt differ`.
+	 */
+	unsigned int contains_data;
+	git_diff_binary_file old_file; /**< The contents of the old file. */
+	git_diff_binary_file new_file; /**< The contents of the new file. */
+} git_diff_binary;
+
+/**
+ * When iterating over a diff, callback that will be made for
+ * binary content within the diff.
+ */
+typedef int GIT_CALLBACK(git_diff_binary_cb)(
+	const git_diff_delta *delta,
+	const git_diff_binary *binary,
+	void *payload);
+
+/**
+ * Structure describing a hunk of a diff.
+ *
+ * A `hunk` is a span of modified lines in a delta along with some stable
+ * surrounding context. You can configure the amount of context and other
+ * properties of how hunks are generated. Each hunk also comes with a
+ * header that described where it starts and ends in both the old and new
+ * versions in the delta.
+ */
+typedef struct {
+	int    old_start;     /**< Starting line number in old_file */
+	int    old_lines;     /**< Number of lines in old_file */
+	int    new_start;     /**< Starting line number in new_file */
+	int    new_lines;     /**< Number of lines in new_file */
+	size_t header_len;    /**< Number of bytes in header text */
+	char   header[GIT_DIFF_HUNK_HEADER_SIZE];   /**< Header text, NUL-byte terminated */
+} git_diff_hunk;
+
+/**
+ * When iterating over a diff, callback that will be made per hunk.
+ */
+typedef int GIT_CALLBACK(git_diff_hunk_cb)(
+	const git_diff_delta *delta,
+	const git_diff_hunk *hunk,
+	void *payload);
+
+/**
+ * Line origin constants.
+ *
+ * These values describe where a line came from and will be passed to
+ * the git_diff_line_cb when iterating over a diff.  There are some
+ * special origin constants at the end that are used for the text
+ * output callbacks to demarcate lines that are actually part of
+ * the file or hunk headers.
+ */
+typedef enum {
+	/* These values will be sent to `git_diff_line_cb` along with the line */
+	GIT_DIFF_LINE_CONTEXT   = ' ',
+	GIT_DIFF_LINE_ADDITION  = '+',
+	GIT_DIFF_LINE_DELETION  = '-',
+
+	GIT_DIFF_LINE_CONTEXT_EOFNL = '=', /**< Both files have no LF at end */
+	GIT_DIFF_LINE_ADD_EOFNL = '>',     /**< Old has no LF at end, new does */
+	GIT_DIFF_LINE_DEL_EOFNL = '<',     /**< Old has LF at end, new does not */
+
+	/* The following values will only be sent to a `git_diff_line_cb` when
+	 * the content of a diff is being formatted through `git_diff_print`.
+	 */
+	GIT_DIFF_LINE_FILE_HDR  = 'F',
+	GIT_DIFF_LINE_HUNK_HDR  = 'H',
+	GIT_DIFF_LINE_BINARY    = 'B' /**< For "Binary files x and y differ" */
+} git_diff_line_t;
+
+/**
+ * Structure describing a line (or data span) of a diff.
+ *
+ * A `line` is a range of characters inside a hunk.  It could be a context
+ * line (i.e. in both old and new versions), an added line (i.e. only in
+ * the new version), or a removed line (i.e. only in the old version).
+ * Unfortunately, we don't know anything about the encoding of data in the
+ * file being diffed, so we cannot tell you much about the line content.
+ * Line data will not be NUL-byte terminated, however, because it will be
+ * just a span of bytes inside the larger file.
+ */
+typedef struct {
+	char   origin;       /**< A git_diff_line_t value */
+	int    old_lineno;   /**< Line number in old file or -1 for added line */
+	int    new_lineno;   /**< Line number in new file or -1 for deleted line */
+	int    num_lines;    /**< Number of newline characters in content */
+	size_t content_len;  /**< Number of bytes of data */
+	git_off_t content_offset; /**< Offset in the original file to the content */
+	const char *content; /**< Pointer to diff text, not NUL-byte terminated */
+} git_diff_line;
+
+/**
+ * When iterating over a diff, callback that will be made per text diff
+ * line. In this context, the provided range will be NULL.
+ *
+ * When printing a diff, callback that will be made to output each line
+ * of text.  This uses some extra GIT_DIFF_LINE_... constants for output
+ * of lines of file and hunk headers.
+ */
+typedef int GIT_CALLBACK(git_diff_line_cb)(
+	const git_diff_delta *delta, /**< delta that contains this data */
+	const git_diff_hunk *hunk,   /**< hunk containing this data */
+	const git_diff_line *line,   /**< line data */
+	void *payload);              /**< user reference data */
+
+/**
+ * Flags to control the behavior of diff rename/copy detection.
+ */
+typedef enum {
+	/** Obey `diff.renames`. Overridden by any other GIT_DIFF_FIND_... flag. */
+	GIT_DIFF_FIND_BY_CONFIG = 0,
+
+	/** Look for renames? (`--find-renames`) */
+	GIT_DIFF_FIND_RENAMES = (1u << 0),
+
+	/** Consider old side of MODIFIED for renames? (`--break-rewrites=N`) */
+	GIT_DIFF_FIND_RENAMES_FROM_REWRITES = (1u << 1),
+
+	/** Look for copies? (a la `--find-copies`). */
+	GIT_DIFF_FIND_COPIES = (1u << 2),
+
+	/** Consider UNMODIFIED as copy sources? (`--find-copies-harder`).
+	 *
+	 * For this to work correctly, use GIT_DIFF_INCLUDE_UNMODIFIED when
+	 * the initial `git_diff` is being generated.
+	 */
+	GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED = (1u << 3),
+
+	/** Mark significant rewrites for split (`--break-rewrites=/M`) */
+	GIT_DIFF_FIND_REWRITES = (1u << 4),
+	/** Actually split large rewrites into delete/add pairs */
+	GIT_DIFF_BREAK_REWRITES = (1u << 5),
+	/** Mark rewrites for split and break into delete/add pairs */
+	GIT_DIFF_FIND_AND_BREAK_REWRITES =
+		(GIT_DIFF_FIND_REWRITES | GIT_DIFF_BREAK_REWRITES),
+
+	/** Find renames/copies for UNTRACKED items in working directory.
+	 *
+	 * For this to work correctly, use GIT_DIFF_INCLUDE_UNTRACKED when the
+	 * initial `git_diff` is being generated (and obviously the diff must
+	 * be against the working directory for this to make sense).
+	 */
+	GIT_DIFF_FIND_FOR_UNTRACKED = (1u << 6),
+
+	/** Turn on all finding features. */
+	GIT_DIFF_FIND_ALL = (0x0ff),
+
+	/** Measure similarity ignoring leading whitespace (default) */
+	GIT_DIFF_FIND_IGNORE_LEADING_WHITESPACE = 0,
+	/** Measure similarity ignoring all whitespace */
+	GIT_DIFF_FIND_IGNORE_WHITESPACE = (1u << 12),
+	/** Measure similarity including all data */
+	GIT_DIFF_FIND_DONT_IGNORE_WHITESPACE = (1u << 13),
+	/** Measure similarity only by comparing SHAs (fast and cheap) */
+	GIT_DIFF_FIND_EXACT_MATCH_ONLY = (1u << 14),
+
+	/** Do not break rewrites unless they contribute to a rename.
+	 *
+	 * Normally, GIT_DIFF_FIND_AND_BREAK_REWRITES will measure the self-
+	 * similarity of modified files and split the ones that have changed a
+	 * lot into a DELETE / ADD pair.  Then the sides of that pair will be
+	 * considered candidates for rename and copy detection.
+	 *
+	 * If you add this flag in and the split pair is *not* used for an
+	 * actual rename or copy, then the modified record will be restored to
+	 * a regular MODIFIED record instead of being split.
+	 */
+	GIT_DIFF_BREAK_REWRITES_FOR_RENAMES_ONLY  = (1u << 15),
+
+	/** Remove any UNMODIFIED deltas after find_similar is done.
+	 *
+	 * Using GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED to emulate the
+	 * --find-copies-harder behavior requires building a diff with the
+	 * GIT_DIFF_INCLUDE_UNMODIFIED flag.  If you do not want UNMODIFIED
+	 * records in the final result, pass this flag to have them removed.
+	 */
+	GIT_DIFF_FIND_REMOVE_UNMODIFIED = (1u << 16)
+} git_diff_find_t;
+
+/**
+ * Pluggable similarity metric
+ */
+typedef struct {
+	int GIT_CALLBACK(file_signature)(
+		void **out, const git_diff_file *file,
+		const char *fullpath, void *payload);
+	int GIT_CALLBACK(buffer_signature)(
+		void **out, const git_diff_file *file,
+		const char *buf, size_t buflen, void *payload);
+	void GIT_CALLBACK(free_signature)(void *sig, void *payload);
+	int GIT_CALLBACK(similarity)(int *score, void *siga, void *sigb, void *payload);
+	void *payload;
+} git_diff_similarity_metric;
+
+/**
+ * Control behavior of rename and copy detection
+ *
+ * These options mostly mimic parameters that can be passed to git-diff.
+ */
+typedef struct {
+	unsigned int version;
+
+	/**
+	 * Combination of git_diff_find_t values (default GIT_DIFF_FIND_BY_CONFIG).
+	 * NOTE: if you don't explicitly set this, `diff.renames` could be set
+	 * to false, resulting in `git_diff_find_similar` doing nothing.
+	 */
+	uint32_t flags;
+
+	/**
+	 * Threshold above which similar files will be considered renames.
+	 * This is equivalent to the -M option. Defaults to 50.
+	 */
+	uint16_t rename_threshold;
+
+	/**
+	 * Threshold below which similar files will be eligible to be a rename source.
+	 * This is equivalent to the first part of the -B option. Defaults to 50.
+	 */
+	uint16_t rename_from_rewrite_threshold;
+
+	/**
+	 * Threshold above which similar files will be considered copies.
+	 * This is equivalent to the -C option. Defaults to 50.
+	 */
+	uint16_t copy_threshold;
+
+	/**
+	 * Threshold below which similar files will be split into a delete/add pair.
+	 * This is equivalent to the last part of the -B option. Defaults to 60.
+	 */
+	uint16_t break_rewrite_threshold;
+
+	/**
+	 * Maximum number of matches to consider for a particular file.
+	 *
+	 * This is a little different from the `-l` option from Git because we
+	 * will still process up to this many matches before abandoning the search.
+	 * Defaults to 1000.
+	 */
+	size_t rename_limit;
+
+	/**
+	 * The `metric` option allows you to plug in a custom similarity metric.
+	 *
+	 * Set it to NULL to use the default internal metric.
+	 *
+	 * The default metric is based on sampling hashes of ranges of data in
+	 * the file, which is a pretty good similarity approximation that should
+	 * work fairly well for both text and binary data while still being
+	 * pretty fast with a fixed memory overhead.
+	 */
+	git_diff_similarity_metric *metric;
+} git_diff_find_options;
+
+#define GIT_DIFF_FIND_OPTIONS_VERSION 1
+#define GIT_DIFF_FIND_OPTIONS_INIT {GIT_DIFF_FIND_OPTIONS_VERSION}
+
+/**
+ * Initialize git_diff_find_options structure
+ *
+ * Initializes a `git_diff_find_options` with default values. Equivalent to creating
+ * an instance with GIT_DIFF_FIND_OPTIONS_INIT.
+ *
+ * @param opts The `git_diff_find_options` struct to initialize.
+ * @param version The struct version; pass `GIT_DIFF_FIND_OPTIONS_VERSION`.
+ * @return Zero on success; -1 on failure.
+ */
+GIT_EXTERN(int) git_diff_find_options_init(
+	git_diff_find_options *opts,
+	unsigned int version);
+
+/** @name Diff Generator Functions
+ *
+ * These are the functions you would use to create (or destroy) a
+ * git_diff from various objects in a repository.
+ */
+/**@{*/
+
+/**
+ * Deallocate a diff.
+ *
+ * @param diff The previously created diff; cannot be used after free.
+ */
+GIT_EXTERN(void) git_diff_free(git_diff *diff);
+
+/**
+ * Create a diff with the difference between two tree objects.
+ *
+ * This is equivalent to `git diff <old-tree> <new-tree>`
+ *
+ * The first tree will be used for the "old_file" side of the delta and the
+ * second tree will be used for the "new_file" side of the delta.  You can
+ * pass NULL to indicate an empty tree, although it is an error to pass
+ * NULL for both the `old_tree` and `new_tree`.
+ *
+ * @param diff Output pointer to a git_diff pointer to be allocated.
+ * @param repo The repository containing the trees.
+ * @param old_tree A git_tree object to diff from, or NULL for empty tree.
+ * @param new_tree A git_tree object to diff to, or NULL for empty tree.
+ * @param opts Structure with options to influence diff or NULL for defaults.
+ * @return 0 or an error code.
+ */
+GIT_EXTERN(int) git_diff_tree_to_tree(
+	git_diff **diff,
+	git_repository *repo,
+	git_tree *old_tree,
+	git_tree *new_tree,
+	const git_diff_options *opts);
+
+/**
+ * Create a diff between a tree and repository index.
+ *
+ * This is equivalent to `git diff --cached <treeish>` or if you pass
+ * the HEAD tree, then like `git diff --cached`.
+ *
+ * The tree you pass will be used for the "old_file" side of the delta, and
+ * the index will be used for the "new_file" side of the delta.
+ *
+ * If you pass NULL for the index, then the existing index of the `repo`
+ * will be used.  In this case, the index will be refreshed from disk
+ * (if it has changed) before the diff is generated.
+ *
+ * @param diff Output pointer to a git_diff pointer to be allocated.
+ * @param repo The repository containing the tree and index.
+ * @param old_tree A git_tree object to diff from, or NULL for empty tree.
+ * @param index The index to diff with; repo index used if NULL.
+ * @param opts Structure with options to influence diff or NULL for defaults.
+ * @return 0 or an error code.
+ */
+GIT_EXTERN(int) git_diff_tree_to_index(
+	git_diff **diff,
+	git_repository *repo,
+	git_tree *old_tree,
+	git_index *index,
+	const git_diff_options *opts);
+
+/**
+ * Create a diff between the repository index and the workdir directory.
+ *
+ * This matches the `git diff` command.  See the note below on
+ * `git_diff_tree_to_workdir` for a discussion of the difference between
+ * `git diff` and `git diff HEAD` and how to emulate a `git diff <treeish>`
+ * using libgit2.
+ *
+ * The index will be used for the "old_file" side of the delta, and the
+ * working directory will be used for the "new_file" side of the delta.
+ *
+ * If you pass NULL for the index, then the existing index of the `repo`
+ * will be used.  In this case, the index will be refreshed from disk
+ * (if it has changed) before the diff is generated.
+ *
+ * @param diff Output pointer to a git_diff pointer to be allocated.
+ * @param repo The repository.
+ * @param index The index to diff from; repo index used if NULL.
+ * @param opts Structure with options to influence diff or NULL for defaults.
+ * @return 0 or an error code.
+ */
+GIT_EXTERN(int) git_diff_index_to_workdir(
+	git_diff **diff,
+	git_repository *repo,
+	git_index *index,
+	const git_diff_options *opts);
+
+/**
+ * Create a diff between a tree and the working directory.
+ *
+ * The tree you provide will be used for the "old_file" side of the delta,
+ * and the working directory will be used for the "new_file" side.
+ *
+ * This is not the same as `git diff <treeish>` or `git diff-index
+ * <treeish>`.  Those commands use information from the index, whereas this
+ * function strictly returns the differences between the tree and the files
+ * in the working directory, regardless of the state of the index.  Use
+ * `git_diff_tree_to_workdir_with_index` to emulate those commands.
+ *
+ * To see difference between this and `git_diff_tree_to_workdir_with_index`,
+ * consider the example of a staged file deletion where the file has then
+ * been put back into the working dir and further modified.  The
+ * tree-to-workdir diff for that file is 'modified', but `git diff` would
+ * show status 'deleted' since there is a staged delete.
+ *
+ * @param diff A pointer to a git_diff pointer that will be allocated.
+ * @param repo The repository containing the tree.
+ * @param old_tree A git_tree object to diff from, or NULL for empty tree.
+ * @param opts Structure with options to influence diff or NULL for defaults.
+ * @return 0 or an error code.
+ */
+GIT_EXTERN(int) git_diff_tree_to_workdir(
+	git_diff **diff,
+	git_repository *repo,
+	git_tree *old_tree,
+	const git_diff_options *opts);
+
+/**
+ * Create a diff between a tree and the working directory using index data
+ * to account for staged deletes, tracked files, etc.
+ *
+ * This emulates `git diff <tree>` by diffing the tree to the index and
+ * the index to the working directory and blending the results into a
+ * single diff that includes staged deleted, etc.
+ *
+ * @param diff A pointer to a git_diff pointer that will be allocated.
+ * @param repo The repository containing the tree.
+ * @param old_tree A git_tree object to diff from, or NULL for empty tree.
+ * @param opts Structure with options to influence diff or NULL for defaults.
+ * @return 0 or an error code.
+ */
+GIT_EXTERN(int) git_diff_tree_to_workdir_with_index(
+	git_diff **diff,
+	git_repository *repo,
+	git_tree *old_tree,
+	const git_diff_options *opts);
+
+/**
+ * Create a diff with the difference between two index objects.
+ *
+ * The first index will be used for the "old_file" side of the delta and the
+ * second index will be used for the "new_file" side of the delta.
+ *
+ * @param diff Output pointer to a git_diff pointer to be allocated.
+ * @param repo The repository containing the indexes.
+ * @param old_index A git_index object to diff from.
+ * @param new_index A git_index object to diff to.
+ * @param opts Structure with options to influence diff or NULL for defaults.
+ * @return 0 or an error code.
+ */
+GIT_EXTERN(int) git_diff_index_to_index(
+	git_diff **diff,
+	git_repository *repo,
+	git_index *old_index,
+	git_index *new_index,
+	const git_diff_options *opts);
+
+/**
+ * Merge one diff into another.
+ *
+ * This merges items from the "from" list into the "onto" list.  The
+ * resulting diff will have all items that appear in either list.
+ * If an item appears in both lists, then it will be "merged" to appear
+ * as if the old version was from the "onto" list and the new version
+ * is from the "from" list (with the exception that if the item has a
+ * pending DELETE in the middle, then it will show as deleted).
+ *
+ * @param onto Diff to merge into.
+ * @param from Diff to merge.
+ * @return 0 or an error code.
+ */
+GIT_EXTERN(int) git_diff_merge(
+	git_diff *onto,
+	const git_diff *from);
+
+/**
+ * Transform a diff marking file renames, copies, etc.
+ *
+ * This modifies a diff in place, replacing old entries that look
+ * like renames or copies with new entries reflecting those changes.
+ * This also will, if requested, break modified files into add/remove
+ * pairs if the amount of change is above a threshold.
+ *
+ * @param diff diff to run detection algorithms on
+ * @param options Control how detection should be run, NULL for defaults
+ * @return 0 on success, -1 on failure
+ */
+GIT_EXTERN(int) git_diff_find_similar(
+	git_diff *diff,
+	const git_diff_find_options *options);
+
+/**@}*/
+
+
+/** @name Diff Processor Functions
+ *
+ * These are the functions you apply to a diff to process it
+ * or read it in some way.
+ */
+/**@{*/
+
+/**
+ * Query how many diff records are there in a diff.
+ *
+ * @param diff A git_diff generated by one of the above functions
+ * @return Count of number of deltas in the list
+ */
+GIT_EXTERN(size_t) git_diff_num_deltas(const git_diff *diff);
+
+/**
+ * Query how many diff deltas are there in a diff filtered by type.
+ *
+ * This works just like `git_diff_num_deltas()` with an extra parameter
+ * that is a `git_delta_t` and returns just the count of how many deltas
+ * match that particular type.
+ *
+ * @param diff A git_diff generated by one of the above functions
+ * @param type A git_delta_t value to filter the count
+ * @return Count of number of deltas matching delta_t type
+ */
+GIT_EXTERN(size_t) git_diff_num_deltas_of_type(
+	const git_diff *diff, git_delta_t type);
+
+/**
+ * Return the diff delta for an entry in the diff list.
+ *
+ * The `git_diff_delta` pointer points to internal data and you do not
+ * have to release it when you are done with it.  It will go away when
+ * the * `git_diff` (or any associated `git_patch`) goes away.
+ *
+ * Note that the flags on the delta related to whether it has binary
+ * content or not may not be set if there are no attributes set for the
+ * file and there has been no reason to load the file data at this point.
+ * For now, if you need those flags to be up to date, your only option is
+ * to either use `git_diff_foreach` or create a `git_patch`.
+ *
+ * @param diff Diff list object
+ * @param idx Index into diff list
+ * @return Pointer to git_diff_delta (or NULL if `idx` out of range)
+ */
+GIT_EXTERN(const git_diff_delta *) git_diff_get_delta(
+	const git_diff *diff, size_t idx);
+
+/**
+ * Check if deltas are sorted case sensitively or insensitively.
+ *
+ * @param diff diff to check
+ * @return 0 if case sensitive, 1 if case is ignored
+ */
+GIT_EXTERN(int) git_diff_is_sorted_icase(const git_diff *diff);
+
+/**
+ * Loop over all deltas in a diff issuing callbacks.
+ *
+ * This will iterate through all of the files described in a diff.  You
+ * should provide a file callback to learn about each file.
+ *
+ * The "hunk" and "line" callbacks are optional, and the text diff of the
+ * files will only be calculated if they are not NULL.  Of course, these
+ * callbacks will not be invoked for binary files on the diff or for
+ * files whose only changed is a file mode change.
+ *
+ * Returning a non-zero value from any of the callbacks will terminate
+ * the iteration and return the value to the user.
+ *
+ * @param diff A git_diff generated by one of the above functions.
+ * @param file_cb Callback function to make per file in the diff.
+ * @param binary_cb Optional callback to make for binary files.
+ * @param hunk_cb Optional callback to make per hunk of text diff.  This
+ *                callback is called to describe a range of lines in the
+ *                diff.  It will not be issued for binary files.
+ * @param line_cb Optional callback to make per line of diff text.  This
+ *                same callback will be made for context lines, added, and
+ *                removed lines, and even for a deleted trailing newline.
+ * @param payload Reference pointer that will be passed to your callbacks.
+ * @return 0 on success, non-zero callback return value, or error code
+ */
+GIT_EXTERN(int) git_diff_foreach(
+	git_diff *diff,
+	git_diff_file_cb file_cb,
+	git_diff_binary_cb binary_cb,
+	git_diff_hunk_cb hunk_cb,
+	git_diff_line_cb line_cb,
+	void *payload);
+
+/**
+ * Look up the single character abbreviation for a delta status code.
+ *
+ * When you run `git diff --name-status` it uses single letter codes in
+ * the output such as 'A' for added, 'D' for deleted, 'M' for modified,
+ * etc.  This function converts a git_delta_t value into these letters for
+ * your own purposes.  GIT_DELTA_UNTRACKED will return a space (i.e. ' ').
+ *
+ * @param status The git_delta_t value to look up
+ * @return The single character label for that code
+ */
+GIT_EXTERN(char) git_diff_status_char(git_delta_t status);
+
+/**
+ * Possible output formats for diff data
+ */
+typedef enum {
+	GIT_DIFF_FORMAT_PATCH        = 1u, /**< full git diff */
+	GIT_DIFF_FORMAT_PATCH_HEADER = 2u, /**< just the file headers of patch */
+	GIT_DIFF_FORMAT_RAW          = 3u, /**< like git diff --raw */
+	GIT_DIFF_FORMAT_NAME_ONLY    = 4u, /**< like git diff --name-only */
+	GIT_DIFF_FORMAT_NAME_STATUS  = 5u, /**< like git diff --name-status */
+	GIT_DIFF_FORMAT_PATCH_ID     = 6u  /**< git diff as used by git patch-id */
+} git_diff_format_t;
+
+/**
+ * Iterate over a diff generating formatted text output.
+ *
+ * Returning a non-zero value from the callbacks will terminate the
+ * iteration and return the non-zero value to the caller.
+ *
+ * @param diff A git_diff generated by one of the above functions.
+ * @param format A git_diff_format_t value to pick the text format.
+ * @param print_cb Callback to make per line of diff text.
+ * @param payload Reference pointer that will be passed to your callback.
+ * @return 0 on success, non-zero callback return value, or error code
+ */
+GIT_EXTERN(int) git_diff_print(
+	git_diff *diff,
+	git_diff_format_t format,
+	git_diff_line_cb print_cb,
+	void *payload);
+
+/**
+ * Produce the complete formatted text output from a diff into a
+ * buffer.
+ *
+ * @param out A pointer to a user-allocated git_buf that will
+ *            contain the diff text
+ * @param diff A git_diff generated by one of the above functions.
+ * @param format A git_diff_format_t value to pick the text format.
+ * @return 0 on success or error code
+ */
+GIT_EXTERN(int) git_diff_to_buf(
+	git_buf *out,
+	git_diff *diff,
+	git_diff_format_t format);
+
+/**@}*/
+
+/*
+ * Low-level file comparison, invoking callbacks per difference.
+ */
+
+/**
+ * Directly run a diff on two blobs.
+ *
+ * Compared to a file, a blob lacks some contextual information. As such,
+ * the `git_diff_file` given to the callback will have some fake data; i.e.
+ * `mode` will be 0 and `path` will be NULL.
+ *
+ * NULL is allowed for either `old_blob` or `new_blob` and will be treated
+ * as an empty blob, with the `oid` set to NULL in the `git_diff_file` data.
+ * Passing NULL for both blobs is a noop; no callbacks will be made at all.
+ *
+ * We do run a binary content check on the blob content and if either blob
+ * looks like binary data, the `git_diff_delta` binary attribute will be set
+ * to 1 and no call to the hunk_cb nor line_cb will be made (unless you pass
+ * `GIT_DIFF_FORCE_TEXT` of course).
+ *
+ * @param old_blob Blob for old side of diff, or NULL for empty blob
+ * @param old_as_path Treat old blob as if it had this filename; can be NULL
+ * @param new_blob Blob for new side of diff, or NULL for empty blob
+ * @param new_as_path Treat new blob as if it had this filename; can be NULL
+ * @param options Options for diff, or NULL for default options
+ * @param file_cb Callback for "file"; made once if there is a diff; can be NULL
+ * @param binary_cb Callback for binary files; can be NULL
+ * @param hunk_cb Callback for each hunk in diff; can be NULL
+ * @param line_cb Callback for each line in diff; can be NULL
+ * @param payload Payload passed to each callback function
+ * @return 0 on success, non-zero callback return value, or error code
+ */
+GIT_EXTERN(int) git_diff_blobs(
+	const git_blob *old_blob,
+	const char *old_as_path,
+	const git_blob *new_blob,
+	const char *new_as_path,
+	const git_diff_options *options,
+	git_diff_file_cb file_cb,
+	git_diff_binary_cb binary_cb,
+	git_diff_hunk_cb hunk_cb,
+	git_diff_line_cb line_cb,
+	void *payload);
+
+/**
+ * Directly run a diff between a blob and a buffer.
+ *
+ * As with `git_diff_blobs`, comparing a blob and buffer lacks some context,
+ * so the `git_diff_file` parameters to the callbacks will be faked a la the
+ * rules for `git_diff_blobs()`.
+ *
+ * Passing NULL for `old_blob` will be treated as an empty blob (i.e. the
+ * `file_cb` will be invoked with GIT_DELTA_ADDED and the diff will be the
+ * entire content of the buffer added).  Passing NULL to the buffer will do
+ * the reverse, with GIT_DELTA_REMOVED and blob content removed.
+ *
+ * @param old_blob Blob for old side of diff, or NULL for empty blob
+ * @param old_as_path Treat old blob as if it had this filename; can be NULL
+ * @param buffer Raw data for new side of diff, or NULL for empty
+ * @param buffer_len Length of raw data for new side of diff
+ * @param buffer_as_path Treat buffer as if it had this filename; can be NULL
+ * @param options Options for diff, or NULL for default options
+ * @param file_cb Callback for "file"; made once if there is a diff; can be NULL
+ * @param binary_cb Callback for binary files; can be NULL
+ * @param hunk_cb Callback for each hunk in diff; can be NULL
+ * @param line_cb Callback for each line in diff; can be NULL
+ * @param payload Payload passed to each callback function
+ * @return 0 on success, non-zero callback return value, or error code
+ */
+GIT_EXTERN(int) git_diff_blob_to_buffer(
+	const git_blob *old_blob,
+	const char *old_as_path,
+	const char *buffer,
+	size_t buffer_len,
+	const char *buffer_as_path,
+	const git_diff_options *options,
+	git_diff_file_cb file_cb,
+	git_diff_binary_cb binary_cb,
+	git_diff_hunk_cb hunk_cb,
+	git_diff_line_cb line_cb,
+	void *payload);
+
+/**
+ * Directly run a diff between two buffers.
+ *
+ * Even more than with `git_diff_blobs`, comparing two buffer lacks
+ * context, so the `git_diff_file` parameters to the callbacks will be
+ * faked a la the rules for `git_diff_blobs()`.
+ *
+ * @param old_buffer Raw data for old side of diff, or NULL for empty
+ * @param old_len Length of the raw data for old side of the diff
+ * @param old_as_path Treat old buffer as if it had this filename; can be NULL
+ * @param new_buffer Raw data for new side of diff, or NULL for empty
+ * @param new_len Length of raw data for new side of diff
+ * @param new_as_path Treat buffer as if it had this filename; can be NULL
+ * @param options Options for diff, or NULL for default options
+ * @param file_cb Callback for "file"; made once if there is a diff; can be NULL
+ * @param binary_cb Callback for binary files; can be NULL
+ * @param hunk_cb Callback for each hunk in diff; can be NULL
+ * @param line_cb Callback for each line in diff; can be NULL
+ * @param payload Payload passed to each callback function
+ * @return 0 on success, non-zero callback return value, or error code
+ */
+GIT_EXTERN(int) git_diff_buffers(
+	const void *old_buffer,
+	size_t old_len,
+	const char *old_as_path,
+	const void *new_buffer,
+	size_t new_len,
+	const char *new_as_path,
+	const git_diff_options *options,
+	git_diff_file_cb file_cb,
+	git_diff_binary_cb binary_cb,
+	git_diff_hunk_cb hunk_cb,
+	git_diff_line_cb line_cb,
+	void *payload);
+
+/* Patch file parsing. */
+
+/**
+ * Options for parsing a diff / patch file.
+ */
+typedef struct {
+	unsigned int version;
+	git_oid_t oid_type;
+} git_diff_parse_options;
+
+/* The current version of the diff parse options structure */
+#define GIT_DIFF_PARSE_OPTIONS_VERSION 1
+
+/* Stack initializer for diff parse options.  Alternatively use
+ * `git_diff_parse_options_init` programmatic initialization.
+ */
+#define GIT_DIFF_PARSE_OPTIONS_INIT \
+	{ GIT_DIFF_PARSE_OPTIONS_VERSION, GIT_OID_DEFAULT }
+
+/**
+ * Read the contents of a git patch file into a `git_diff` object.
+ *
+ * The diff object produced is similar to the one that would be
+ * produced if you actually produced it computationally by comparing
+ * two trees, however there may be subtle differences.  For example,
+ * a patch file likely contains abbreviated object IDs, so the
+ * object IDs in a `git_diff_delta` produced by this function will
+ * also be abbreviated.
+ *
+ * This function will only read patch files created by a git
+ * implementation, it will not read unified diffs produced by
+ * the `diff` program, nor any other types of patch files.
+ *
+ * @param out A pointer to a git_diff pointer that will be allocated.
+ * @param content The contents of a patch file
+ * @param content_len The length of the patch file contents
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_diff_from_buffer(
+	git_diff **out,
+	const char *content,
+	size_t content_len
+#ifdef GIT_EXPERIMENTAL_SHA256
+	, git_diff_parse_options *opts
+#endif
+	);
+
+/**
+ * This is an opaque structure which is allocated by `git_diff_get_stats`.
+ * You are responsible for releasing the object memory when done, using the
+ * `git_diff_stats_free()` function.
+ */
+typedef struct git_diff_stats git_diff_stats;
+
+/**
+ * Formatting options for diff stats
+ */
+typedef enum {
+	/** No stats*/
+	GIT_DIFF_STATS_NONE = 0,
+
+	/** Full statistics, equivalent of `--stat` */
+	GIT_DIFF_STATS_FULL = (1u << 0),
+
+	/** Short statistics, equivalent of `--shortstat` */
+	GIT_DIFF_STATS_SHORT = (1u << 1),
+
+	/** Number statistics, equivalent of `--numstat` */
+	GIT_DIFF_STATS_NUMBER = (1u << 2),
+
+	/** Extended header information such as creations, renames and mode changes, equivalent of `--summary` */
+	GIT_DIFF_STATS_INCLUDE_SUMMARY = (1u << 3)
+} git_diff_stats_format_t;
+
+/**
+ * Accumulate diff statistics for all patches.
+ *
+ * @param out Structure containing the diff statistics.
+ * @param diff A git_diff generated by one of the above functions.
+ * @return 0 on success; non-zero on error
+ */
+GIT_EXTERN(int) git_diff_get_stats(
+	git_diff_stats **out,
+	git_diff *diff);
+
+/**
+ * Get the total number of files changed in a diff
+ *
+ * @param stats A `git_diff_stats` generated by one of the above functions.
+ * @return total number of files changed in the diff
+ */
+GIT_EXTERN(size_t) git_diff_stats_files_changed(
+	const git_diff_stats *stats);
+
+/**
+ * Get the total number of insertions in a diff
+ *
+ * @param stats A `git_diff_stats` generated by one of the above functions.
+ * @return total number of insertions in the diff
+ */
+GIT_EXTERN(size_t) git_diff_stats_insertions(
+	const git_diff_stats *stats);
+
+/**
+ * Get the total number of deletions in a diff
+ *
+ * @param stats A `git_diff_stats` generated by one of the above functions.
+ * @return total number of deletions in the diff
+ */
+GIT_EXTERN(size_t) git_diff_stats_deletions(
+	const git_diff_stats *stats);
+
+/**
+ * Print diff statistics to a `git_buf`.
+ *
+ * @param out buffer to store the formatted diff statistics in.
+ * @param stats A `git_diff_stats` generated by one of the above functions.
+ * @param format Formatting option.
+ * @param width Target width for output (only affects GIT_DIFF_STATS_FULL)
+ * @return 0 on success; non-zero on error
+ */
+GIT_EXTERN(int) git_diff_stats_to_buf(
+	git_buf *out,
+	const git_diff_stats *stats,
+	git_diff_stats_format_t format,
+	size_t width);
+
+/**
+ * Deallocate a `git_diff_stats`.
+ *
+ * @param stats The previously created statistics object;
+ * cannot be used after free.
+ */
+GIT_EXTERN(void) git_diff_stats_free(git_diff_stats *stats);
+
+/**
+ * Patch ID options structure
+ *
+ * Initialize with `GIT_PATCHID_OPTIONS_INIT`. Alternatively, you can
+ * use `git_diff_patchid_options_init`.
+ *
+ */
+typedef struct git_diff_patchid_options {
+	unsigned int version;
+} git_diff_patchid_options;
+
+#define GIT_DIFF_PATCHID_OPTIONS_VERSION 1
+#define GIT_DIFF_PATCHID_OPTIONS_INIT { GIT_DIFF_PATCHID_OPTIONS_VERSION }
+
+/**
+ * Initialize git_diff_patchid_options structure
+ *
+ * Initializes a `git_diff_patchid_options` with default values. Equivalent to
+ * creating an instance with `GIT_DIFF_PATCHID_OPTIONS_INIT`.
+ *
+ * @param opts The `git_diff_patchid_options` struct to initialize.
+ * @param version The struct version; pass `GIT_DIFF_PATCHID_OPTIONS_VERSION`.
+ * @return Zero on success; -1 on failure.
+ */
+GIT_EXTERN(int) git_diff_patchid_options_init(
+	git_diff_patchid_options *opts,
+	unsigned int version);
+
+/**
+ * Calculate the patch ID for the given patch.
+ *
+ * Calculate a stable patch ID for the given patch by summing the
+ * hash of the file diffs, ignoring whitespace and line numbers.
+ * This can be used to derive whether two diffs are the same with
+ * a high probability.
+ *
+ * Currently, this function only calculates stable patch IDs, as
+ * defined in git-patch-id(1), and should in fact generate the
+ * same IDs as the upstream git project does.
+ *
+ * @param out Pointer where the calculated patch ID should be stored
+ * @param diff The diff to calculate the ID for
+ * @param opts Options for how to calculate the patch ID. This is
+ *  intended for future changes, as currently no options are
+ *  available.
+ * @return 0 on success, an error code otherwise.
+ */
+GIT_EXTERN(int) git_diff_patchid(git_oid *out, git_diff *diff, git_diff_patchid_options *opts);
+
+GIT_END_DECL
+
+/** @} */
+
+#endif