Merge remote-tracking branch 'origin/main' into cgraph-write

6 files changed, 112 insertions, 8 deletions

diff --git a/include/git2/checkout.h b/include/git2/checkout.h
index ca6f17aa6..c7aeee431 100644
--- a/include/git2/checkout.h
+++ b/include/git2/checkout.h
@@ -178,6 +178,12 @@ typedef enum {
 	GIT_CHECKOUT_DONT_WRITE_INDEX = (1u << 23),
 
 	/**
+	 * Show what would be done by a checkout.  Stop after sending
+	 * notifications; don't update the working directory or index.
+	 */
+	GIT_CHECKOUT_DRY_RUN = (1u << 24),
+	
+	/**
 	 * THE FOLLOWING OPTIONS ARE NOT YET IMPLEMENTED
 	 */
 
diff --git a/include/git2/errors.h b/include/git2/errors.h
index 8887b3299..de51582d5 100644
--- a/include/git2/errors.h
+++ b/include/git2/errors.h
@@ -42,14 +42,14 @@ typedef enum {
 	GIT_ECONFLICT       = -13,	/**< Checkout conflicts prevented operation */
 	GIT_ELOCKED         = -14,	/**< Lock file prevented operation */
 	GIT_EMODIFIED       = -15,	/**< Reference value does not match expected */
-	GIT_EAUTH           = -16,      /**< Authentication error */
-	GIT_ECERTIFICATE    = -17,      /**< Server certificate is invalid */
+	GIT_EAUTH           = -16,	/**< Authentication error */
+	GIT_ECERTIFICATE    = -17,	/**< Server certificate is invalid */
 	GIT_EAPPLIED        = -18,	/**< Patch/merge has already been applied */
-	GIT_EPEEL           = -19,      /**< The requested peel operation is not possible */
-	GIT_EEOF            = -20,      /**< Unexpected EOF */
-	GIT_EINVALID        = -21,      /**< Invalid operation or input */
+	GIT_EPEEL           = -19,	/**< The requested peel operation is not possible */
+	GIT_EEOF            = -20,	/**< Unexpected EOF */
+	GIT_EINVALID        = -21,	/**< Invalid operation or input */
 	GIT_EUNCOMMITTED    = -22,	/**< Uncommitted changes in index prevented operation */
-	GIT_EDIRECTORY      = -23,      /**< The operation is not valid for a directory */
+	GIT_EDIRECTORY      = -23,	/**< The operation is not valid for a directory */
 	GIT_EMERGECONFLICT  = -24,	/**< A merge conflict exists and cannot continue */
 
 	GIT_PASSTHROUGH     = -30,	/**< A user-configured callback refused to act */
diff --git a/include/git2/odb.h b/include/git2/odb.h
index 702e1bd30..dd484553f 100644
--- a/include/git2/odb.h
+++ b/include/git2/odb.h
@@ -391,6 +391,20 @@ GIT_EXTERN(int) git_odb_write_pack(
 	void *progress_payload);
 
 /**
+ * Write a `multi-pack-index` file from all the `.pack` files in the ODB.
+ *
+ * If the ODB layer understands pack files, then this will create a file called
+ * `multi-pack-index` next to the `.pack` and `.idx` files, which will contain
+ * an index of all objects stored in `.pack` files. This will allow for
+ * O(log n) lookup for n objects (regardless of how many packfiles there
+ * exist).
+ *
+ * @param db object database where the `multi-pack-index` file will be written.
+ */
+GIT_EXTERN(int) git_odb_write_multi_pack_index(
+	git_odb *db);
+
+/**
  * Determine the object-ID (sha1 hash) of a data buffer
  *
  * The resulting SHA-1 OID will be the identifier for the data
diff --git a/include/git2/sys/midx.h b/include/git2/sys/midx.h
new file mode 100644
index 000000000..e3d749829
--- /dev/null
+++ b/include/git2/sys/midx.h
@@ -0,0 +1,74 @@
+/*
+ * 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_sys_git_midx_h__
+#define INCLUDE_sys_git_midx_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+
+/**
+ * @file git2/midx.h
+ * @brief Git multi-pack-index routines
+ * @defgroup git_midx Git multi-pack-index routines
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Create a new writer for `multi-pack-index` files.
+ *
+ * @param out location to store the writer pointer.
+ * @param pack_dir the directory where the `.pack` and `.idx` files are. The
+ * `multi-pack-index` file will be written in this directory, too.
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_midx_writer_new(
+		git_midx_writer **out,
+		const char *pack_dir);
+
+/**
+ * Free the multi-pack-index writer and its resources.
+ *
+ * @param w the writer to free. If NULL no action is taken.
+ */
+GIT_EXTERN(void) git_midx_writer_free(git_midx_writer *w);
+
+/**
+ * Add an `.idx` file to the writer.
+ *
+ * @param w the writer
+ * @param idx_path the path of an `.idx` file.
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_midx_writer_add(
+		git_midx_writer *w,
+		const char *idx_path);
+
+/**
+ * Write a `multi-pack-index` file to a file.
+ *
+ * @param w the writer
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_midx_writer_commit(
+		git_midx_writer *w);
+
+/**
+ * Dump the contents of the `multi-pack-index` to an in-memory buffer.
+ *
+ * @param midx Buffer where to store the contents of the `multi-pack-index`.
+ * @param w the writer
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_midx_writer_dump(
+		git_buf *midx,
+		git_midx_writer *w);
+
+/** @} */
+GIT_END_DECL
+#endif
diff --git a/include/git2/sys/odb_backend.h b/include/git2/sys/odb_backend.h
index 4dba460af..9ae0ed9b3 100644
--- a/include/git2/sys/odb_backend.h
+++ b/include/git2/sys/odb_backend.h
@@ -85,6 +85,13 @@ struct git_odb_backend {
 		git_indexer_progress_cb progress_cb, void *progress_payload);
 
 	/**
+	 * If the backend supports pack files, this will create a
+	 * `multi-pack-index` file which will contain an index of all objects
+	 * across all the `.pack` files.
+	 */
+	int GIT_CALLBACK(writemidx)(git_odb_backend *);
+
+	/**
 	 * "Freshens" an already existing object, updating its last-used
 	 * time.  This occurs when `git_odb_write` was called, but the
 	 * object already existed (and will not be re-written).  The
diff --git a/include/git2/types.h b/include/git2/types.h
index 4d5c72324..aac8e42e2 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -96,8 +96,8 @@ typedef struct git_odb_stream git_odb_stream;
 /** A stream to write a packfile to the ODB */
 typedef struct git_odb_writepack git_odb_writepack;
 
-/** a writer for commit-graph files. */
-typedef struct git_commit_graph_writer git_commit_graph_writer;
+/** a writer for multi-pack-index files. */
+typedef struct git_midx_writer git_midx_writer;
 
 /** An open refs database handle. */
 typedef struct git_refdb git_refdb;
@@ -108,6 +108,9 @@ typedef struct git_refdb_backend git_refdb_backend;
 /** A git commit-graph */
 typedef struct git_commit_graph git_commit_graph;
 
+/** a writer for commit-graph files. */
+typedef struct git_commit_graph_writer git_commit_graph_writer;
+
 /**
  * Representation of an existing git repository,
  * including all its object contents