Introduce git_process class that invokes processes

libgit2 · ethomson · Aug 31, 2023 · Apr 22, 2023 · Feb 15, 2023 · Feb 23, 2023
commit bc97d01c039f004a05a5457bace11f3c3e26beb5
diff --git a/src/util/process.h b/src/util/process.h
@@ -0,0 +1,156 @@
+/*
+ * 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_process_h__
+#define INCLUDE_process_h__
+
+typedef struct git_process git_process;
+
+typedef struct {
+	int capture_in  : 1,
+	    capture_out : 1,
+	    capture_err : 1,
+	    exclude_env : 1;
+
+	char *cwd;
+} git_process_options;
+
+typedef enum {
+	GIT_PROCESS_STATUS_NONE,
+	GIT_PROCESS_STATUS_NORMAL,
+	GIT_PROCESS_STATUS_ERROR
+} git_process_result_status;
+
+#define GIT_PROCESS_RESULT_INIT { GIT_PROCESS_STATUS_NONE }
+
+typedef struct {
+	git_process_result_status status;
+	int exitcode;
+	int signal;
+} git_process_result;
+
+#define GIT_PROCESS_OPTIONS_INIT { 0 }
+
+/**
+ * Create a new process.  The command to run should be specified as the
+ * element of the `arg` array.
+ *
+ * This function will add the given environment variables (in `env`)
+ * to the current environment.  Operations on environment variables
+ * are not thread safe, so you may not modify the environment during
+ * this call.  You can avoid this by setting `exclude_env` in the
+ * options and providing the entire environment yourself.
+ *
+ * @param out location to store the process
+ * @param args the command (with arguments) to run
+ * @param args_len the length of the args array
+ * @param env environment variables to add (or NULL)
+ * @param env_len the length of the env len
+ * @param opts the options for creating the process
+ * @return 0 or an error code
+ */
+extern int git_process_new(
+	git_process **out,
+	const char **args,
+	size_t args_len,
+	const char **env,
+	size_t env_len,
+	git_process_options *opts);
+
+#ifdef GIT_WIN32
+
+/* Windows path parsing is tricky; this helper function is for testing. */
+extern int git_process__cmdline(
+	git_str *out,
+	const char **in,
+	size_t in_len);
+
+#endif
+
+/**
+ * Start the process.
+ *
+ * @param process the process to start
+ * @return 0 or an error code
+ */
+extern int git_process_start(git_process *process);
+
+/**
+ * Read from the process's stdout.  The process must have been created with
+ * `capture_out` set to true.
+ *
+ * @param process the process to read from
+ * @param buf the buf to read into
+ * @param count maximum number of bytes to read
+ * @return number of bytes read or an error code
+ */
+extern ssize_t git_process_read(git_process *process, void *buf, size_t count);
+
+/**
+ * Write to the process's stdin.  The process must have been created with
+ * `capture_in` set to true.
+ *
+ * @param process the process to write to
+ * @param buf the buf to write
+ * @param count maximum number of bytes to write
+ * @return number of bytes written or an error code
+ */
+extern ssize_t git_process_write(git_process *process, const void *buf, size_t count);
+
+/**
+ * Wait for the process to finish.
+ *
+ * @param result the result of the process or NULL
+ * @param process the process to wait on
+ */
+extern int git_process_wait(git_process_result *result, git_process *process);
+
+/**
+ * Close the input pipe from the child.
+ *
+ * @param process the process to close the pipe on
+ */
+extern int git_process_close_in(git_process *process);
+
+/**
+ * Close the output pipe from the child.
+ *
+ * @param process the process to close the pipe on
+ */
+extern int git_process_close_out(git_process *process);
+
+/**
+ * Close the error pipe from the child.
+ *
+ * @param process the process to close the pipe on
+ */
+extern int git_process_close_err(git_process *process);
+
+/**
+ * Close all resources that are used by the process.  This does not
+ * wait for the process to complete.
+ *
+ * @parma process the process to close
+ */
+extern int git_process_close(git_process *process);
+
+/**
+ * Place a human-readable error message in the given git buffer.
+ *
+ * @param msg the buffer to store the message
+ * @param result the process result that produced an error
+ */
+extern int git_process_result_msg(git_str *msg, git_process_result *result);
+
+/**
+ * Free a process structure
+ *
+ * @param process the process to free
+ */
+extern void git_process_free(git_process *process);
+
+#endif