Add Activity to view the Git commit log (#1056)

7 files changed, 240 insertions, 17 deletions

diff --git a/app/src/main/java/com/zeapo/pwdstore/PasswordStore.kt b/app/src/main/java/com/zeapo/pwdstore/PasswordStore.kt
index d9afc7c9..6a0d707c 100644
--- a/app/src/main/java/com/zeapo/pwdstore/PasswordStore.kt
+++ b/app/src/main/java/com/zeapo/pwdstore/PasswordStore.kt
@@ -48,6 +48,7 @@ import com.zeapo.pwdstore.crypto.BasePgpActivity.Companion.getLongName
 import com.zeapo.pwdstore.crypto.DecryptActivity
 import com.zeapo.pwdstore.crypto.PasswordCreationActivity
 import com.zeapo.pwdstore.git.BaseGitActivity
+import com.zeapo.pwdstore.git.log.GitLogActivity
 import com.zeapo.pwdstore.git.GitOperationActivity
 import com.zeapo.pwdstore.git.GitServerConfigActivity
 import com.zeapo.pwdstore.git.config.AuthMode
diff --git a/app/src/main/java/com/zeapo/pwdstore/git/GitConfigActivity.kt b/app/src/main/java/com/zeapo/pwdstore/git/GitConfigActivity.kt
index 9205e7fc..89376bfd 100644
--- a/app/src/main/java/com/zeapo/pwdstore/git/GitConfigActivity.kt
+++ b/app/src/main/java/com/zeapo/pwdstore/git/GitConfigActivity.kt
@@ -4,20 +4,24 @@
  */
 package com.zeapo.pwdstore.git
 
+import android.content.Intent
 import android.os.Bundle
 import android.os.Handler
 import android.util.Patterns
 import androidx.core.os.postDelayed
 import androidx.lifecycle.lifecycleScope
+import com.github.ajalt.timberkt.e
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.snackbar.Snackbar
 import com.zeapo.pwdstore.R
 import com.zeapo.pwdstore.databinding.ActivityGitConfigBinding
 import com.zeapo.pwdstore.git.config.GitSettings
+import com.zeapo.pwdstore.git.log.GitLogActivity
 import com.zeapo.pwdstore.utils.PasswordRepository
 import com.zeapo.pwdstore.utils.viewBinding
 import kotlinx.coroutines.launch
 import org.eclipse.jgit.lib.Constants
+import org.eclipse.jgit.lib.Repository
 
 class GitConfigActivity : BaseGitActivity() {
 
@@ -33,23 +37,7 @@ class GitConfigActivity : BaseGitActivity() {
         else
             binding.gitUserName.setText(GitSettings.authorName)
         binding.gitUserEmail.setText(GitSettings.authorEmail)
-        val repo = PasswordRepository.getRepository(PasswordRepository.getRepositoryDirectory())
-        if (repo != null) {
-            try {
-                val objectId = repo.resolve(Constants.HEAD)
-                val ref = repo.getRef("refs/heads/${GitSettings.branch}")
-                val head = if (ref.objectId.equals(objectId)) ref.name else "DETACHED"
-                binding.gitCommitHash.text = String.format("%s (%s)", objectId.abbreviate(8).name(), head)
-
-                // enable the abort button only if we're rebasing
-                val isRebasing = repo.repositoryState.isRebasing
-                binding.gitAbortRebase.isEnabled = isRebasing
-                binding.gitAbortRebase.alpha = if (isRebasing) 1.0f else 0.5f
-            } catch (ignored: Exception) {
-            }
-        }
-        binding.gitAbortRebase.setOnClickListener { lifecycleScope.launch { launchGitOperation(BREAK_OUT_OF_DETACHED) } }
-        binding.gitResetToRemote.setOnClickListener { lifecycleScope.launch { launchGitOperation(REQUEST_RESET) } }
+        setupTools()
         binding.saveButton.setOnClickListener {
             val email = binding.gitUserEmail.text.toString().trim()
             val name = binding.gitUserName.text.toString().trim()
@@ -66,4 +54,50 @@ class GitConfigActivity : BaseGitActivity() {
             }
         }
     }
+
+    /**
+     * Sets up the UI components of the tools section.
+     */
+    private fun setupTools() {
+        val repo = PasswordRepository.getRepository(null)
+        if (repo != null) {
+            binding.gitHeadStatus.text = headStatusMsg(repo)
+            // enable the abort button only if we're rebasing
+            val isRebasing = repo.repositoryState.isRebasing
+            binding.gitAbortRebase.isEnabled = isRebasing
+            binding.gitAbortRebase.alpha = if (isRebasing) 1.0f else 0.5f
+        }
+        binding.gitLog.setOnClickListener {
+            try {
+                intent = Intent(this, GitLogActivity::class.java)
+                startActivity(intent)
+            } catch (ex: Exception) {
+                e(ex) { "Failed to start GitLogActivity" }
+            }
+        }
+        binding.gitAbortRebase.setOnClickListener { lifecycleScope.launch { launchGitOperation(BREAK_OUT_OF_DETACHED) } }
+        binding.gitResetToRemote.setOnClickListener { lifecycleScope.launch { launchGitOperation(REQUEST_RESET) } }
+    }
+
+    /**
+     * Returns a user-friendly message about the current state of HEAD.
+     *
+     * The state is recognized to be either pointing to a branch or detached.
+     */
+    private fun headStatusMsg(repo: Repository): String {
+        return try {
+            val headRef = repo.getRef(Constants.HEAD)
+            if (headRef.isSymbolic) {
+                val branchName = headRef.target.name
+                val shortBranchName = Repository.shortenRefName(branchName)
+                getString(R.string.git_head_on_branch, shortBranchName)
+            } else {
+                val commitHash = headRef.objectId.abbreviate(8).name()
+                getString(R.string.git_head_detached, commitHash)
+            }
+        } catch (ex: Exception) {
+            e(ex) { "Error getting HEAD reference" }
+            getString(R.string.git_head_missing)
+        }
+    }
 }
diff --git a/app/src/main/java/com/zeapo/pwdstore/git/log/GitCommit.kt b/app/src/main/java/com/zeapo/pwdstore/git/log/GitCommit.kt
new file mode 100644
index 00000000..d2425592
--- /dev/null
+++ b/app/src/main/java/com/zeapo/pwdstore/git/log/GitCommit.kt
@@ -0,0 +1,18 @@
+/*
+ * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package com.zeapo.pwdstore.git.log
+
+import java.util.Date
+
+/**
+ * Basic information about a git commit.
+ *
+ * @property hash full-length hash of the commit object.
+ * @property shortMessage the commit's short message (i.e. title line).
+ * @property authorName name of the commit's author without email address.
+ * @property time time when the commit was created.
+ */
+data class GitCommit(val hash: String, val shortMessage: String, val authorName: String, val time: Date)
diff --git a/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogActivity.kt b/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogActivity.kt
new file mode 100644
index 00000000..8c1c0f09
--- /dev/null
+++ b/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogActivity.kt
@@ -0,0 +1,38 @@
+/*
+ * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package com.zeapo.pwdstore.git.log
+
+import android.os.Bundle
+import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.LinearLayoutManager
+import com.zeapo.pwdstore.databinding.ActivityGitLogBinding
+import com.zeapo.pwdstore.git.BaseGitActivity
+import com.zeapo.pwdstore.utils.viewBinding
+
+/**
+ * Displays the repository's git commits in git-log fashion.
+ *
+ * It provides basic information about each commit by way of a non-interactive RecyclerView.
+ */
+class GitLogActivity : BaseGitActivity() {
+
+    private val binding by viewBinding(ActivityGitLogBinding::inflate)
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(binding.root)
+        supportActionBar?.setDisplayHomeAsUpEnabled(true)
+        createRecyclerView()
+    }
+
+    private fun createRecyclerView() {
+        binding.gitLogRecyclerView.apply {
+            setHasFixedSize(true)
+            addItemDecoration(DividerItemDecoration(context, LinearLayoutManager.VERTICAL))
+            adapter = GitLogAdapter()
+        }
+    }
+}
diff --git a/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogAdapter.kt b/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogAdapter.kt
new file mode 100644
index 00000000..a15e7f7e
--- /dev/null
+++ b/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogAdapter.kt
@@ -0,0 +1,56 @@
+/*
+ * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package com.zeapo.pwdstore.git.log
+
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import androidx.recyclerview.widget.RecyclerView
+import com.github.ajalt.timberkt.e
+import com.zeapo.pwdstore.databinding.GitLogRowLayoutBinding
+import java.text.DateFormat
+import java.util.Date
+
+private fun shortHash(hash: String): String {
+    return hash.substring(0 until 8)
+}
+
+private fun stringFrom(date: Date): String {
+    return DateFormat.getDateTimeInstance().format(date)
+}
+
+/**
+ * @see GitLogActivity
+ */
+class GitLogAdapter : RecyclerView.Adapter<GitLogAdapter.ViewHolder>() {
+
+    private val model = GitLogModel()
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
+        val inflater = LayoutInflater.from(parent.context)
+        val binding = GitLogRowLayoutBinding.inflate(inflater, parent, false)
+        return ViewHolder(binding)
+    }
+
+    override fun onBindViewHolder(viewHolder: ViewHolder, position: Int) {
+        val commit = model.get(position)
+        if (commit == null) {
+            e { "There is no git commit for view holder at position $position." }
+            return
+        }
+        viewHolder.bind(commit)
+    }
+
+    override fun getItemCount() = model.size
+
+    class ViewHolder(private val binding: GitLogRowLayoutBinding) : RecyclerView.ViewHolder(binding.root) {
+
+        fun bind(commit: GitCommit) = with(binding) {
+            gitLogRowMessage.text = commit.shortMessage
+            gitLogRowHash.text = shortHash(commit.hash)
+            gitLogRowTime.text = stringFrom(commit.time)
+        }
+    }
+}
diff --git a/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogModel.kt b/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogModel.kt
new file mode 100644
index 00000000..22c1ec78
--- /dev/null
+++ b/app/src/main/java/com/zeapo/pwdstore/git/log/GitLogModel.kt
@@ -0,0 +1,53 @@
+/*
+ * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+package com.zeapo.pwdstore.git.log
+
+import com.github.ajalt.timberkt.e
+import com.zeapo.pwdstore.utils.PasswordRepository
+import com.zeapo.pwdstore.utils.hash
+import com.zeapo.pwdstore.utils.time
+import org.eclipse.jgit.api.Git
+import org.eclipse.jgit.revwalk.RevCommit
+
+private fun commits(): Iterable<RevCommit> {
+    val repo = PasswordRepository.getRepository(null)
+    if (repo == null) {
+        e { "Could not access git repository" }
+        return listOf()
+    }
+    return try {
+        Git(repo).log().call()
+    } catch (exc: Exception) {
+        e(exc) { "Failed to obtain git commits" }
+        listOf()
+    }
+}
+
+/**
+ * Provides [GitCommit]s from a git-log of the password git repository.
+ *
+ * All commits are acquired on the first request to this object.
+ */
+class GitLogModel {
+
+    // All commits are acquired here at once. Acquiring the commits in batches would not have been
+    // entirely sensible because the amount of computation required to obtain commit number n from
+    // the log includes the amount of computation required to obtain commit number n-1 from the log.
+    // This is because the commit graph is walked from HEAD to the last commit to obtain.
+    // Additionally, tests with 1000 commits in the log have not produced a significant delay in the
+    // user experience.
+    private val cache: MutableList<GitCommit> by lazy {
+        commits().map {
+            GitCommit(it.hash, it.shortMessage, it.authorIdent.name, it.time)
+        }.toMutableList()
+    }
+    val size = cache.size
+
+    fun get(index: Int): GitCommit? {
+        if (index >= size) e { "Cannot get git commit with index $index. There are only $size." }
+        return cache.getOrNull(index)
+    }
+}
diff --git a/app/src/main/java/com/zeapo/pwdstore/utils/Extensions.kt b/app/src/main/java/com/zeapo/pwdstore/utils/Extensions.kt
index 561b8d99..edc01776 100644
--- a/app/src/main/java/com/zeapo/pwdstore/utils/Extensions.kt
+++ b/app/src/main/java/com/zeapo/pwdstore/utils/Extensions.kt
@@ -28,6 +28,9 @@ import com.zeapo.pwdstore.git.GitCommandExecutor
 import com.zeapo.pwdstore.git.operation.GitOperation
 import com.zeapo.pwdstore.utils.PasswordRepository.Companion.getRepositoryDirectory
 import java.io.File
+import java.util.Date
+import org.eclipse.jgit.lib.ObjectId
+import org.eclipse.jgit.revwalk.RevCommit
 
 const val OPENPGP_PROVIDER = "org.sufficientlysecure.keychain"
 
@@ -162,3 +165,23 @@ val Context.autofillManager: AutofillManager?
 fun File.isInsideRepository(): Boolean {
     return canonicalPath.contains(getRepositoryDirectory().canonicalPath)
 }
+
+/**
+ * Unique SHA-1 hash of this commit as hexadecimal string.
+ *
+ * @see RevCommit.id
+ */
+val RevCommit.hash: String
+    get() = ObjectId.toString(id)
+
+/**
+ * Time this commit was made with second precision.
+ *
+ * @see RevCommit.commitTime
+ */
+val RevCommit.time: Date
+    get() {
+        val epochSeconds = commitTime.toLong()
+        val epochMilliseconds = epochSeconds * 1000
+        return Date(epochMilliseconds)
+    }